Citation
Effects of Oyster Shell Shape and Thickness on Absorption of Electron Beam, Gamma Ray, and X-Ray Irradiation

Material Information

Title:
Effects of Oyster Shell Shape and Thickness on Absorption of Electron Beam, Gamma Ray, and X-Ray Irradiation
Creator:
HURST JR, ARTHUR GRANT
Copyright Date:
2008

Subjects

Subjects / Keywords:
Clams ( jstor )
Curvature ( jstor )
Dosage ( jstor )
Eggshells ( jstor )
Electron beams ( jstor )
Irradiation ( jstor )
Linear regression ( jstor )
Meats ( jstor )
Mussels ( jstor )
Oysters ( jstor )
City of Gainesville ( local )

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Source Institution:
University of Florida
Holding Location:
University of Florida
Rights Management:
Copyright Arthur Grant Hurst, Jr. Permission granted to University of Florida to digitize and display this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
Embargo Date:
4/17/2006
Resource Identifier:
495638391 ( OCLC )

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Full Text












EFFECTS OF OYSTER SHELL SHAPE AND THICKNESS
ON ABSORPTION OF ELECTRON BEAM, GAMMA RAY, AND X-RAY
IRRADIATION















By

ARTHUR GRANT HURST, JR.


A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE

UNIVERSITY OF FLORIDA


2005

































Copyright 2005

by

Arthur Grant Hurst, Jr.


































To my wife Ashley, my parents, and my family for their continued support
and encouragement















ACKNOWLEDGMENTS

I would like to extend thanks and gratitude to my committee chairman and major

advisor, Dr. Gary E. Rodrick. Without this guidance his work would not be possible.

Thanks are due also to my supervisory committee members, Dr. Ronald Schmidt and Dr.

Sally Williams, for all their help and guidance in the completion of this research. I would

like to express my appreciation to Carl Gillis and Florida Accelerator Services and

Technology of Gainesville, FL, for providing me the opportunity to perform research at

this facility. Thanks are also due to Food Technology Service, Inc. of Mulberry, FL, for

allowing me the opportunity to perform research at its facility. I would also like to thank

the National Center of Electron Beam Food Research at Texas A & M University of

College Station, TX, for aiding us in our research and for the efficiency and consideration

of the staff.

Bill Leeming and Southern Cross Sea Farms, Inc. of Cedar Key, FL, deserve

recognition for always providing top-quality clams. The efforts of fellow master's

student Daniel Periu as well as all of my lab mates were invaluable in the completion of

this project.

In conclusion, I would like to thank my parents, Arthur and Darlene Hurst, for all

of their love and support. I would also like to thank my wife, Ashley, for all of her love

and support. Without her encouragement and support this research would not have been

possible















TABLE OF CONTENTS

page

A C K N O W L E D G M E N T S ................................................................................................. iv

LIST OF TABLES .................. .................. ................. ............ .............. vii

LIST OF FIGURES .................................................... ............ .............. .. viii

ABSTRACT ........ .............. ............. ........ .......... .......... xii

CHAPTER

1 IN TR O D U C TIO N ......................................................................... .... .. ........

2 REVIEW OF LITERATURE ............................................................ .............4

V ibrio vulnificus ................................................................... ..................
R radiation ...................................... ................................... .................... 6
R radiation Sources ............................................................................ .7
R radiation D ose .................................................... ..................... 8
O y sters ............................................................................ . 9
C lam s ............................................................................. ................ 11
M u s se ls ...............................................................................1 2

3 MATERIALS AND METHODS ........................................... .......................... 14

Source of O y sters ..................................................................................... 14
Source of Clams .................. .................................... .......... .............. 14
Sources of M ussels ............................................... .................... ........... ..... 15
D osim eter Source and R leading .............................................. .......................... 15
Oyster, Clam and Mussel Measuring Protocol.........................................................15
Electron B eam and X -ray Protocol..................................... .......................... ......... 16
G am m a Irradiation Protocol ................................................ ............................. 17
S ta tistic s ................................................................................................................. 1 8

4 RESULTS AND D ISCU SSION ........................................... ............................ 19

Oyster Irradiation with Electron Beam ............................................. ...............19
Oyster Irradiation w ith X -Ray ....................................................... ............. 26
Oyster Irradiation w ith G am m a ......................................................... ............... 32
Clam Irradiation with Electron Beam .......................................................................39



v









C lam Irradiation w ith X -ray ............................................... ................................. 45
Clam Irradiation with Gamma ............... ............... .................... 51
Mussel Irradiation with Electron Beam ....................................... ...............58
M ussel Irradiation w ith X -ray .............................................................. ...............65
M ussel Irradiation w ith G am m a ....................................................... .... ........... 71

5 SUMMARY AND CONCLUSIONS.......................................................................80

APPENDIX

A OYSTER, CLAM, AND MUSSEL MEASUREMENTS .......................................82

O y ster M easu rem ents ...................................................................... ....................82
Clam M easurem ents ..................................................... ........ ..... 88
M ussel M easurem ent ................................................... .............. .............. 94
Oyster Irradiation D ose M easurem ents ........................................ .....................100
Clam Irradiated D ose M easurem ents..................................... ....................... 107
Mussel Irradiation Dose Measurements .............. .........................................113

B OYSTER, CLAM AND MUSSEL PICTURES............... .................119

L IST O F R E F E R E N C E S ...................................................................... ..................... 122

BIOGRAPHICAL SKETCH ............................................................. ............... 126
















LIST OF TABLES


Table page

A-i Oyster W eight M easurements in g (5/1/05) .................................. .................82

A-2 Oyster Dimension Measurements in cm (5/3/05) ......................................... 84

A-3 Oyster Thickness Measurements in cm (5/4/05) .............. ....................................86

A-4 Clam W eight M easurements in g (4/29/05).................................. .................88

A-5 Clam Dimension Measurement in cm (5/10/05) .................................................90

A-6 Clam Thickness Measurement in cm (5/12/05) ................................................. 92

A-7 Mussel Weight Measurement in g (5/12/05) .......................................................94

A-8 Mussel Dimension Measurement in cm (5/20/05) ....................................... 96

A-9 Mussel Thickness Measurement in cm (5/22/05) ......................................... 98

A-10 Electron Beam irradiated oysters in kGy .................................... ............... 100

A-11 X-ray Irradiated Oysters in kGy .................................. ............... 102

A-12 Gamma Ray Irradiated Oysters in kGy .................. .............. ...............104

A-13 Electron Beam Irradiated Clam s in kGy ..................................... .................107

A-14 X-ray Irradiated Clams in kGy................................ .......................... 109

A-15 Gamma Ray Irradiated Clams in kGy ................................... ......... ............... 111

A-16 Electron Beam irradiated mussels in kGy ..........................................................113

A-17 X-ray Irradiated M ussels in kGy ............... ............................. ................ 115

A-18 Gamma Ray Irradiated Mussels in kGy .............. ......... ..................... 117















LIST OF FIGURES


Figure page

4-1 The internal absorbed dose oyster shells compared to the external absorbed dose
of the top shell of oysters after exposure to electron beam at 1 kGy .....................19

4-2 The internal absorbed dose oyster shells as compared to the external absorbed
dose of the top shell of oysters after exposure at 3 kGy.......................................21

4-3 Percent external top shell dose absorbed internally in oyster shells compared to
mean thickness of top shell of oysters irradiated at doses of IkGy and 3 kGy.......22

4-4 Percent external top shell dose absorbed internally in oyster shells as compared
to curvature of top shell of the oysters irradiated at doses of IkGy and 3 kGy.......23

4-5 Percent external dose absorbed internally in oyster shells compared to weight of
oyster shells irradiated with electron beam at doses of IkGy and 3 kGy. ...............25

4-6 The internal absorbed dose oyster shells as compared to the external absorbed
dose of the top shell of oysters after exposure to x-ray at 1 kGy..........................26

4-7 The internal absorbed dose of oyster shells as compared to the external
absorbed dose of the top shell of oysters after exposure to x-ray at 3 kGy. ...........28

4-8 Percent external shell dose absorbed internally in oyster shells compared to
thickness of oyster shells irradiated at doses of IkGy and 3 kGy with x-ray. .........29

4-9 Percent external top shell dose absorbed internally in oyster shells compared to
curvature of oyster shells irradiated at doses of IkGy and 3 kGy with x-ray at......30

4-10 Percent external top shell dose absorbed internally in oyster shells compared to
weight of top shell of oysters irradiated at doses of IkGy and 3 kGy with x-ray....31

4-11 The internal absorbed dose oyster shells as compared to the external absorbed
dose of the top shell of oysters after exposure to gamma at 1 kGy.......................33

4-12 The internal absorbed dose of oyster shells as compared to the external
absorbed dose of the top shell of oysters after exposure to gamma at 3 kGy at. ....34

4-13 Percent external shell dose absorbed internally in oyster shells compared to
thickness of oyster shell irradiated at doses of 1 kGy and 3 kGy with gamma. ......35









4-14 Percent external top shell dose absorbed internally in oyster shells compared to
curvature of oyster shells irradiated at doses of IkGy and 3 kGy with gamma at...36

4-15 Percent external top shell dose absorbed internally in oyster shells compared to
weight of oyster shells irradiated at doses of IkGy and 3 kGy with gamma...........37

4-16 The internal absorbed dose clam shells as compared to the external absorbed
dose of the top shell of clams after exposure to electron beam at 1 kGy at...........40

4-17 The internal absorbed dose clam shells as compared to the external absorbed
dose of the top shell of clams after exposure at 3 kGy at.....................................41

4-18 Percent external top shell dose absorbed internally in clam shells compared to
thickness of clam shells irradiated with electron beam at IkGy and 3 kGy. ...........42

4-19 Percent external top shell dose absorbed internally in clam shells compared to
curvature of clam shells irradiated with electron beam at IkGy and 3 kGy............44

4-20 Percent external top shell dose absorbed internally in clam shells compared to
weight of clam shells irradiated at doses of IkGy and 3 kGy with electron beam..45

4-21 The internal absorbed dose clam shells as compared to the external absorbed
dose of the top shell of clams after exposure to x-ray at 1 kGy............................46

4-22 The internal absorbed dose of clam shells as compared to the external absorbed
dose of the top shell of clams after exposure to x-ray at 3 kGy ...........................47

4-23 Percent external top shell dose absorbed internally in clam shells compared to
thickness of clam shells irradiated at doses of IkGy and 3 kGy with x-ray. ...........49

4-24 Percent external top shell dose absorbed internally in clam shells as compared to
the curvature of clam shells irradiated at doses of IkGy and 3 kGy with x-ray......50

4-25 Percent external top shell dose absorbed internally in clam shells compared to
weight of clam shells irradiated at doses of IkGy and 3 kGy with x-ray. ...............51

4-26 The internal absorbed dose clam shells as compared to the external absorbed
dose of the top shell of clams after exposure to gamma at 1 kGy.........................52

4-27 The internal absorbed dose of clam shells as compared to the external absorbed
dose of the top shell of clams after exposure to gamma at 3 kGy.........................53

4-28 Percent external top shell dose absorbed internally in clam shells compared to
thickness of clam shells irradiated at doses of 1 kGy and 3 kGy with gamma.......55

4-29 Percent external top shell dose absorbed internally in clam shells compared to
curvature of clam shells irradiated at doses of IkGy and 3 kGy with gamma at.....56









4-30 Percent external top shell dose absorbed internally in clam shells compared to
weight of clam shells irradiated at doses of IkGy and 3 kGy with gamma.............57

4-31 The internal absorbed dose mussel shells as compared to the external absorbed
dose of the top shell of mussels after exposure to electron beam at 1 kGy.............58

4-32 The internal absorbed dose mussel shells as compared to the external absorbed
dose of the top shell of mussels after exposure at 3 kGy. ....................................60

4-33 Percent external top shell dose absorbed internally in mussel shells compared to
thickness of mussel shells irradiated with electron beam IkGy and 3 kGy.............61

4-34 Percent external top shell dose absorbed internally in mussel shells compared to
curvature of mussel shells irradiated at doses of IkGy and 3 kGy. .........................62

4-35 Percent external top shell dose absorbed internally in mussel shells compared to
weight of mussel shells irradiated at IkGy and 3 kGy with electron beam.............64

4-36 The internal absorbed dose mussel shells as compared to the external absorbed
dose of the top shell of mussels after exposure to x-ray at 1 kGy ........................65

4-37 The internal absorbed dose of mussel shells as compared to the external
absorbed dose of the top shell of mussels after exposure to x-ray at 3 kGy...........67

4-38 Percent external top shell dose absorbed internally in mussel shells compared to
thickness of mussel shells irradiated at doses of IkGy and 3 kGy with x-ray.........68

4-39 Percent external top shell dose absorbed internally in mussel shells compared to
curvature of mussel shells irradiated at doses of IkGy and 3 kGy with x-ray.........69

4-40 Percent external top shell dose absorbed internally in mussel shells compared to
weight of mussel shells irradiated at doses of IkGy and 3 kGy with x-ray ...........70

4-41 The internal absorbed dose mussel shells as compared to the external absorbed
dose of the top shell of mussels after exposure to gamma at 1 kGy ....................72

4-42 The internal absorbed dose of mussel shells as compared to the external
absorbed dose of the top shell of mussels after exposure to gamma at 3 kGy........73

4-43 Percent external top shell dose absorbed internally in mussel shells compared to
thickness of mussel shells irradiated at 1 kGy and 3 kGy with gamma at...............74

4-44 Percent external top shell dose absorbed internally in mussel shells compared to
curvature of mussel shells irradiated at doses of IkGy and 3 kGy with gamma. ....75

4-45 Percent external top shell dose absorbed internally in mussel shells compared to
weight of mussel shells irradiated at doses of IkGy and 3 kGy with gamma..........77









B-1 Picture of oysters with dosimeter envelopes placed on them (6/8/05) ...................119

B-2 Picture of clams with dosimeter envelopes placed on them (6/8/05)...................120

B-3 Picture of mussels with dosimeter envelopes placed on them (6/8/05) ...............121















Abstract of Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Science

EFFECTS OF OYSTER SHELL SHAPE AND THICKNESS ON ABSORPTION OF
ELECTRON BEAM, GAMMA RAY, AND X-RAY IRRADIATION

By

Arthur Grant Hurst, Jr.

December 2005

Chair: Gary E. Rodrick
Major Department: Food Science and Human Nutrition

The overall objective of this research was to determine the effects of shape and

thickness on the absorption of electron beam, gamma ray and x-ray irradiation levels in

raw oysters, clams and mussels. Groups of 100 oysters, 100 clams and 100 mussels were

shucked of their meats and measured for dimensions and thickness. Wild Apalachicola

oysters, farm raised Cedar Key clams and farm raised mussels from China were used for

this research. The oysters, clams and mussels were divided up into groups of 50, attached

with 3 film dosimeter strips each and irradiated at doses of 1 kilogray (KGy) and 3

kilograys (KGy). After irradiation the dosimeters were read using a spectrophotometer to

determine the internal and external doses.

Electron beam irradiation had the least uniform dose of the three sources. X-ray

irradiation had a more uniform dose than electron beam. Gamma ray irradiation had the

most uniform dose of the three doses. Oysters had a wider range of thicknesses and

dimensions than the clams and mussels. Clams had a smaller range of thicknesses and









dimensions than the oysters, but the mussels had the smallest range of thicknesses and

dimensions. The electron beam and x-ray sources also showed signs of a concentration

of irradiation within the shell. In both of the sources the internal absorbed dose was

greater than the external or given dose.

There are statistical differences between the internal and external doses with all

three types of irradiation. Statistical analysis showed differences in the amount of

external doses absorbed internally between electron beam, x-ray and gamma ray.

Observations suggest that the thicknesses, curvatures and weights of the shells do not

independently have a significant effect on the amount of irradiation absorbed with in the

shell. The oysters also had the least uniform internal dose absorption. Internal clam

doses were more uniform than the internal oyster doses but not as uniform as the internal

mussel doses.














CHAPTER 1
INTRODUCTION

Oysters, clams and mussels are of great importance to those who work with the

shellfish industry and those who consume them. For many, these bivalve shellfish are a

delicacy and for others a source of livelihood. However, these bivalve shellfish have

received much criticism in the past five years for their potential to cause disease and even

death. The illnesses and deaths are primarily due to the marine bacteria genera Vibrio

especially V vulnificus and V parahemolyticus (Tamplin et al., 1982). Both of these

organisms can be fatal, when consumed by at risk individuals. Vibrio vulnificus is

responsible for approximately 85 hospitalizations and approximately 35 deaths per year

in the United States (Centers for Disease Control and Prevention [CDC], 2003). Certain

individuals are at higher risk for this disease and likely to become infected from these

organisms. At risk individuals include individuals who suffer from a compromised

immune system, cirrhosis, diabetes, acquired immunodeficiency syndrome, cancer,

hemachromatosis or liver disease (Blake et al., 1979). This group of at risk individuals

makes up a large number of potential victims that has been estimated to be as large as 10-

15 million in the USA.

In light of the morbidity and mortality concerns of these Vibrio diseases transmitted

to at risk individuals by consuming raw oysters and clams, the shellfish industry is

regulated to reduce or eliminate the public health risk of Vibrio. Efforts to reduce the

associated morbidity and mortality from raw oyster consumption have led to increased

regulation of shellfish waters as well as increased efforts to inform the public through









public bulletins and mandatory safety warnings in Florida, Louisiana and Texas. Despite

the efforts of increased regulation and information, the health concern still persists. This

has led regulatory authorities to issue new regionally specific food safety mandates that

pose significant historical changes in oyster commerce. The mandate (Food and Drug

Administration [FDA], 2003) calls for immediate compliance goals before the end of

2004 and additional, more stringent goals before the end of 2006. The goals include

implementation of new, innovative post-harvest treatments to reduce specific bacterial

loads on raw oyster products. The regulatory expectations call for technology that has

not been proven both in terms of food safety or market acceptance. Processing aids (e.g.,

depuration, relaying, freezing, pressure and irradiation) have been investigated with

respect to reducing levels of V. vulnificus and V parahemolyticus (Blogoslowski and

Stewart, 1983; Motes and DePaola, 1996; Mestey and Rodrick, 2003; Berlin et al., 1996;

Dixon, 1992).

Irradiation of oysters is a processing technique which has promise for reducing the

safety concern of these organisms. While irradiation has not yet been approved for

seafood including oysters, irradiation of oysters has been investigated for decades. Vibrio

is destroyed by irradiation. Kilgen et al. (1988) assessed shellstock oysters and showed

that all Vibrio pathogens were significantly reduced to undetectable levels at a dose of 1

kGy. Although the Vibrio threat can be reduced or eliminated through irradiation many

obstacles must be overcome before it can be put into practice.

Perhaps the biggest obstacle to overcome is the obstruction and lack of uniformity

regarding absorption through the shell into the meat of the oyster. Dixon (1996) found

that dosimeters placed inside oyster shells received approximately half of the calculated









dose that was calculated by the irradiation facility. The dose of radiation absorbed by the

meat is affected by the natural physical barrier of the shell. Shells may vary greatly in

size, thickness, and shape so absorption may vary even from oyster to oyster. In order for

irradiation to be a viable option in the shellfish industry the differences in oyster shells

size, thickness, and shape must be considered.

The overall objective of this research was to compare and contrast the percentage

of absorption of irradiation from a gamma ray source, electron beam and x-ray

irradiation. The specific objectives of this research were to (1) examine the differences in

absorbed dose of irradiation between the external top and internal sections of the shells of

oysters, clams and mussels; (2) compare and contrast the absorption of irradiation in

three different types of shellfish; (3) compare the thickness and curvature of the shells to

the internal dose.














CHAPTER 2
REVIEW OF LITERATURE

Vibrio vulnificus

A public health risk exists for certain high risk individuals who consume raw or

undercooked oysters and clams. Crassostrea virginica, the American oyster and

Mercenaria campechiensis, hard-shelled clam have been implicated in several foodborne

outbreaks (Blake et al., 1980; Blake, 1983; DuPont, 1986). Many different bacterial and

viral agents such as Vibrio, Salmonella, .lNge/llu, Hepatitis virus and Norwalk virus have

been isolated from shellfish (Blake et al., 1980). Although all of the organisms can cause

problems in oysters and clams Vibrio is the most serious organism in shellfish.

V. vulnificus is a Gram negative, halophilic rod-shaped bacterium that is found in

estuarine and marine environments (Blake, 1983; DuPont, 1986). The U.S. Gulf Coast is

the most common place to find V. vulnificus (Tamplin et al., 1982), yet V vulnificus has

been isolated from the Atlantic Coast and Pacific Coast (Oliver et al., 1983; Kelly and

Stroh, 1988). Both salinity and water temperature play a important role in the detection

of V. vulnificus. Levels of V vulnificus are much higher during the warmer summer

months and lower in waters with salinities higher than 35 ppt (Kelly, 1982). Vibrio

vulnificus is a ubiquitous marine and estuarine microorganism that can be found

throughout the world. This is considered naturally occurring organism whose presence in

the environment is not related to fecal pollution (Tamplin et al., 1982).

Infection by V vulnificus arises from the ingestion of raw or inadequately cooked

oysters or clams or by exposure of wounds to contaminated water. A primary septicemia









results from ingestion of V vulnificus and is accompanied by gastroenteritis, chills, and

fever. Individuals who become infected through a wound show symptoms of rapid

swelling erythema around the wound, as well as, fever and chills (Blake et al., 1980).

Wound infections can also cause myositis, severe cellulites and are likely to lead to gas

gangrene (Klontz et al., 1988).

Infections by V vulnificus are onset rapidly with a median incubation period of

approximately 12-16 hours (Blake et al., 1980). Vibrio vulnificus infections can be life

threatening. Approximately 50% of patients who develop primary septicemia die (Morris

and Black, 1985). In patients developing hypotension within 12 hours after hospital

admission the mortality rate can be as high as 90% (Klontz et al., 1988). After primary

septicemia sets in, many patients begin to develop secondary lesions on their extremities

that can result in necrotizing vasculitis in the muscles, which often result in amputations

(Howard et al., 1986). Several epidemiological studies have been conducted which

suggest that a relationship between several preexisting conditions and primary

septicemia. Cirrhosis, diabetes, hemochromatosis, kidney failure, liver and iron disorders

and any other immunocompromised conditions may cause individuals to be at risk (Blake

et al., 1979; Tacket et al., 1984). The effect of V. vulnificus on at risk individuals has led

regulatory authorities and industry to investigate ways to reduce or eliminate the impact

of this organism on the public.

Since 1980, the shellfish regulatory agencies and industry have put forth a strong

effort to reduce the health risk related to oysters and clams. Dry cold storage is the

current accepted practice for storage and handling of oysters. Oysters are harvested,

slightly cleaned, culled and either placed in croaker sacks or wax boxes and stored at









refrigeration at 34-360F in the dry cold storage method (Dixon, 1996). Bacterial

reduction and shelf life extension are not achieved by this method. This ineffective

method has led industry and regulatory authorities to look for innovative methods such as

irradiation.

Irradiation is an effective method in reducing V. vulnificus in oysters. When a large

enough dose of irradiation is applied the bacteria are reduced. Low doses of irradiation

are effective in significantly reducing V. vulnificus in shell stock oysters (Dixon, 1992).

The potential for irradiation to reduce V. vulnificus has led irradiation of shellfish to be

investigated.

Radiation

Radiation is the movement of energy from a source through matter or space.

Sound, light, microwaves, and a wide range of other forms of energy are all forms of

radiation. Ionizing and non-ionizing radiation are the main two irradiation categories of

Non-ionizing radiation, such as visible light and microwaves, lacks the energy to remove

electrons from the orbit of atoms. Ionizing radiation can interact with atoms and cause

electrons to become excited or move from a lower energy level to a higher energy level.

When significant ionizing radiation is present the electron can be ejected from the atom.

Electron separation from the atom causes ionization, creating a positive or negative ion

(Urbain, 1986). Once the electron is free from the atom, it can interact with other

materials and cause chemical structure changes in the material. In the case of food

irradiation, these chemical structure changes occur within the microorganisms present in

the food, cause the microorganisms damage and eventually death (Elias and Cohen,

1983). Death occurs in microorganisms either by the radiation interacting directly with

cell components or with adjacent molecules in the cell. Radiation damage to the cell can









be caused directly by the ionizing ray or by free radicals,( -H and -OH,) created by the

breakdown of water. The radicals, (primarily -OH) creates single strand and double

strand DNA breaks in the genetic material. Single and double strand breaks in DNA

occur due to chemical damage to the purine bases, pyrimadine bases and deoxyribose

sugar (Farkas, 2001). If the genetic material is not repaired then the cell cannot produce

crucial materials from the genetic material and will die (Grez et al., 1983).

Radiation Sources

Three types of ionizing radiation, gamma rays, x rays and electrons, are used in

food irradiation. The most prevalent form of ionizing radiation used in food irradiation is

the use of gamma rays. In food irradiation processing, two sources, Cobalt-60 and

Cesium-137, are used for producing gamma rays. Decay of the unstable radioactive

nucleus of Cobalt-60 and Cesium-137 cause gamma rays to be produced (Urbain, 1986).

Cobalt-60 produces two gamma rays with energy levels of 1.17 million electron volts

(MeV) and 1.33 MeV. Cesium-137 produces only one gamma ray with an energy level

of 0.66 MeV. Neither of these sources have the potential to produce radioactive food.

For significant radioactivity to be imparted into food energy levels larger than 15 MeV

must be used. The half-life of Cobalt-60 is 5.3 years. Cesium-137 however has a half-

life of 30.2 years. Gamma rays produced by Cobalt-60 and Cesium-137 have good

penetrating power, but can not be turned on and off. They are always producing

radiation. Containment and storage to prevent environmental contamination are a major

concern with these two sources. Both Cobalt-60 and Cesium-137 are generally

approved by the FDA in food products approved for irradiation (CFR, 1994).

Machine source electron beams and X-rays are also used in food irradiation

processing, yet these are not as widely used as gamma rays. The energy levels for both









of these sources also are not large enough to convey radioactivity into the food. Electron

beams must have energy levels of less than 10 MeV and X-rays must have energy levels

less than 10 MeV to be allowed in the United States (21CFR179). Electron beams can be

efficiently created in high doses in a short amount of time and there is not a constant

radioactive source that must be contained. With electron beam machine sources the

radiation can be turned on and off, but electrons do not penetrate as well as gamma rays.

X-rays have greater penetrating power and can be turned on and off therefore

contamination is less of an issue. However, production of x-rays is not very efficient.

Radiation Dose

The nomenclature used to determine radiation dose have changed over time. In

older literature the rad was used as the unit for radiation dose delivered to a product or

radiation dose absorbed. One rad is equal to 100 ergs of absorbed energy per gram.

Current literature mostly uses the International System of Units (SI) unit of Gray (Gy).

One Gray is equal to 100 rads and 1 joule of energy absorbed per kilogram of food

(Urbain, 1986). The Food and Drug Administration (FDA) has approved several foods

at different doses mostly ranging from 1 kGy to 7 kGy. Fresh foods are approved for 1

kGy to delay maturation, all foods are approved at 1 kGy to prevent insect contamination,

Poultry is approved at 3 kGy to reduce pathogens, fresh red meat is approved at 4.5 kGy

and frozen red meat is approved at 7 kGy to reduce pathogens (Henkel, 1998) by the

FDA and the U.S. Department of Agriculture Food Safety Inspection Service (FSIS). All

of the doses are rather low. The only exception is spices which are approved up to 30

kGy (Henkel, 1998).

One major concern with oysters, clams, mussels and other bivalve shellfish is the

lack of uniformity in the dose. The desired target area for the radiation, the meat, is









shielded by a shell that may vary greatly in thickness, conformation and shape. This shell

may reduce the dose being applied to the food. This lack of uniformity creates a situation

where researchers must either choose a maximum dose or a minimum dose as the focus

(Stein 1995). In this situation the researcher selects a minimum dose (Dmin) based on the

amount of radiation needed to achieve desired effects and a maximum dose (Dmax) where

no extra undesirable effects are created (Stein 1995). The extent of dose absorbed may

vary depending on a variety of factors. Dixon (1996) found that the dose calculated by

Food Technology Services of Mulberry, FL, a gamma ray food irradiation facility, was

twice the dose received by internal dosimeters. The calculated dose given to the product

may vary greatly from the dose that the meat of the product actually receives.

Research of irradiation of shellfish is focused around two possible advantages. The

first major advantage of irradiation is the deduction of pathogens such as Vibrio in the

shellfish such as oysters and clams. The second major advantage is the possibility of

increasing shelf life of shellfish such as mussels. The major disadvantage of irradiating

shellfish is the increased cost of the process. Overall the possibility of increasing the

safety of shellfish with only slightly increased cost is very promising.

Oysters

Irradiation is a relatively new form of food processing compared to drying or

heating. For nearly a century irradiation has been studied for processing food.

Strawberries were processed with irradiation in 1916 (Webb et al., 1987). Many types of

food have been irradiated since then. Fruits, vegetables, meats, fish, shellfish as well as

many other types of food have been irradiated.

Bivalve shellfish, such as oysters, clams and mussels are one type of food that is

currently being researched as a candidate for irradiation to reduce pathogens. Irradiation









of oysters has been studied since the 1950s as a possible method of reducing V. vulnificus

and as a method to extend shelf life. Gardner and Watts (1957) used ionizing radiation to

treat oyster meats at low doses of 630 rads (0.63 kGy), 830 rads (0.83 kGy) and 3500

rads (3.5 kGy). They observed that undesirable "oxidized" and "grassy" odors developed

respectively in raw and cooked irradiated oyster meats. Gardner and Watts (1957)

concluded that irradiation would not be successful in oyster preservation due to the

continuation of enzyme action even with doses of 3500 rads (3.5 kGy) and 50C storage.

In 1966, Novak and others irradiated canned oyster meats at 2 kGy. The irradiated

and control oysters were stored on ice for 23 days and tested at 0, 7, 14, 21, and 23 days.

A trained taste panel was used to determine that irradiated oyster meats were adequate for

up to 28 days and non irradiated oyster meats were acceptable only up to seven days

(Novak et al., 1966). Slavin et al. (1966) concluded that oyster meats optimally irradiated

at 2 kGy and stored at 0.60C resulted in shelf life of 21 to 28 days. Metlitskii et al.

(1968) showed that oysters irradiated at 5 kGy and stored at 20C have a 60 day shelf life.

Liuzzo et al. (1970) studied the optimum dose that would extend shelf life and

result in the least alteration in food components of shucked oyster meats. They

determined that a dose of 2.5 kGy would extend the shelf life of oyster meat to seven

days on ice. Sensory quality of the irradiated meats was not significantly different from

the non irradiated meats until the seventh day. Liuzzo et al. (1970) also determined that

doses above 1 kGy altered the B-vitamin retention, percent moisture, percent ash,

glycogen content and soluble sugar content of oyster meats.

Kilgen et al. (1988) examined shellstock oysters and showed that all Vibrio

pathogens were significantly reduced to undetectable levels at a dose of 1 kGy. Doses of









1 kGy were not lethal to oysters. There were also no significant sensory changes at a

dose of 1 kGy. Mallet et al. (1991) irradiated shellstock oysters from Massachusetts and

determined that the survival times of oysters through six days was not affected by doses

of up to 2.5 kGy. Mallet et al. (1991) concluded that doses of 2.5 kGy or lower produced

a median shelf life of greater than 25 days. Also, Mallett et al. (1991) also used a trained

taste panel to determine that oysters irradiated at doses up to 3 kGy were acceptable.

Hepatitis A virus and rotavirus SA11 in oysters and clams were also studied by Mallett et

al. (1991). A dose of 2 kGy gave a Dio value for hepatitis A virus and a dose of 2.4 kGy

gave a Dio value for rotavirus Sal 1.

In contrast to Kilgen et al. (1988), Dixon (1992) showed that 1 3 kGy doses of

gamma radiation stored at 40C to 60C were not effective in significantly extending the

shelf life of Florida shellstock oysters longer than the non irradiated controls. In addition,

Rodrick and Dixon (1994) found that the bacterial levels of V. vulnificus, fecals and

overall bacteria were reduced by about 2 logs with doses of 1 kGy and 3 kGy. But this

reduction only lasted a few days before the counts started to rise again to an even greater

number than the initial amount. Also, in contrast to previous work, the shelf life for these

oysters was not significantly extended as claimed by Mallet et al. (1991).

Clams

Clams have also been studied with respect to irradiation as a possible method to

reduce V. vulnificus or extend shelf life. Nickerson (1963), studied irradiation of clams

and determined that clam meats had a shelf life of 28 days with a dose of 4.5 kGy. Also,

at doses up to 8.0 kGy Nickerson (1963) showed that irradiated clam meats stored at 60C

for 40 days showed no detectable differences from non-irradiated clam meats. Slavin et

al. (1963) also found that 4.5 kGy irradiated clams stored at 60C were equal in quality to









non irradiated clam meats. A taste panel was used by Connors and Steinberg (1964) to

determine that clam meats irradiated at 2.5 kGy to 5.5 kGy were not significantly

different from non irradiated clam meats. Yamada and Amano (1965) determined the

optimum dose range to be 100-450 krads (0.1-0.45 kGy) to obtain a shelf life of four

weeks at 00C-20C in Venerupis semiddecus sata clams. Carver et al. (1967) determined

that shucked surf clam meats, Spisula solidissima, air packed in plastic pouches have an

optimum dose of 450 krads with a shelf life of 50 days at 0.60C. Non treated clam meats

have a shelf life of 10 days at 0.60C. Carver et al. (1967) also determined that clams

treated with doses of 100 200 krads have a shelf life of 40 days at 0.60C. Harewood et

al (1994) evaluated the effects of gamma radiation on bacterial and viral loads as well as

shelf life in Mercenaria mercenaria hard shell clams. Radiation Dio values were 1.32

kGy for total coliforms, 1.39 kGy for fecal coliforms, 1.54 kGy forE. coli, 2.71 kGy for

C. perfringens and 13.5 kGy for F-coliphage.

Mussels

Irradiation of Mussels has been studied as well though to a lesser extent than have

clams and oysters. Irradiation of mussels is of concern due to the possibility of

increasing shelf life. Lohaharanu et al. (1972) examined shucked mussel meats and

determined that the optimum dose of irradiation was 150-250 krads (0.15-0.25 kGy). The

shelf life for the irradiated mussels were six weeks at 3 C and the shelf life for the

nonirradiated mussels was three weeks at 3C. Since mussels are not very susceptible to

V. vulnificus and are generally eaten cooked irradiation of mussels has not been

researched to the degree that clams and oysters have. Extension of shelf life is one

possible benefit of irradiating oysters however.






13


Oysters, clams and mussels only make up a small part of the body of research of

food irradiation. However, irradiation of oysters, clams and mussels may prove to be

important in providing a safe way of producing products which are safer for the consumer

and have a longer shelf life.














CHAPTER 3
MATERIALS AND METHODS

This research included examination of oysters, clams, and mussels for differences

and similarities between shape, weight and size. The absorption of gamma ray and

electron beam irradiation in oysters, clams, and mussels were compared and contrasted.

Also this research included analyzing the shape, weight and size of the oysters, clams,

and mussels and their shells.

Source of Oysters

Florida shellstock oysters were used for analysis in this research. The source of the

oysters used in this analysis was Leavins Seafood, Inc. of Apalachicola, FL. Summer

oysters were harvested by Leavins Seafood, Inc. from approved shellfish harvesting

waters in the Apalachicola area. Leavins delivered the oysters to us at the Interstate 10

Agricultural Inspection Station in Live Oak, FL via refrigerated truck. The oysters were

transported on ice from Live Oak to the University of Florida in Gainesville, FL.

Source of Clams

Farm raised Florida hard shell clams were used in this research. The source of the

clams used in this research was harvested by Southern Cross Sea Farms, Inc. The clams

were harvested from approved shellfish harvesting waters in Cedar Key, FL. Southern

Cross Sea Farms breads, raises and harvests clams in Cedar Key, FL. The clams were

transported in coolers from Cedar Key to the University of Florida.









Sources of Mussels

Farm raised mussels from China were purchased from Northwest Seafood, Inc. in

Gainesville, FL and transported on ice to the University of Florida. The mussels were

imported, frozen and distributed by Beaver Street Fisheries in Jacksonville, FL.

Dosimeter Source and Reading

FWT 60-00 dosimeter strips produced by Far West Technology Inc. of Goleta, CA

were used to examine the dose of irradiation received in the inside and outside of the

oyster, clams, and mussel shells. The Florida Accelerator Services Technology (FAST)

facility's dosimetery lab in Gainesville, FL was used to prepare and read all of the

dosimeter strips used in this research. These dosimeter strips were determined by Carl

Gilus the dosimetry expert for FAST to be the best fit for our dose, 1KGy to 3KGy, and

the spectrophotometer equipment available to us at FAST. All of the FWT 60-00

dosimeter strips were read using the FWT-100 Radiachromic Reader at FAST's

dosimetery lab produced by Far West Technology Inc.

Oyster, Clam and Mussel Measuring Protocol

Oysters, clams and mussels (100 of each) were irradiated and assessed. Each of the

oysters, clams and mussels were all measured following this protocol. All of the

shellstock shellfish were weighed and measured at the University of Florida, Department

of Food Science and Human Nutrition. The meats were shucked from the shells with a

shucking knife, taking care to remove all of the meat. Both meat and shell were weighed,

to the nearest tenth of a gram, individually for each shellfish. After weighing the meat

was discarded. The top and bottom of the shell were also weighed individually and

together. The shells were measured for thickness, with calipers, at various locations over

the shell at a variety of places mapping the shell. Upper and lower shell parts were









compared to each other to determine the differences in weight between the upper and

lower parts of the shell. Overall shell weight was compared to meat weight. The thickest

and thinnest places were compared for each shell. Also, the thickness for each shell was

averaged. The heights, at the highest part of the shell, of both the upper and lower parts

of the shell were measured. In addition, the length of the upper and lower parts of each

shell (at the longest part) was measured. The length and height for each shell was

compared and contrasted. These comparisons were then used to determine the relative

curvature of each shell.

Electron Beam and X-ray Protocol

The electron beam source for this research was the National Center for Electron

Beam Food Research (NCEBFR) facility at Texas A and M University at College Station,

TX. The National Center for Electron Beam Food Research uses a 10 MeV Linear

Accelerator to irradiate food for research and commercial uses. The accelerator is a

linear Varian Accelerator in a Titan designed system.

The X-ray source for this research was also the National Center for Electron Beam

Food Research facility (NCEBFR) at Texas A and M University at College Station, TX.

The National Center for Electron Beam Food Research uses a 10 MeV mechanical

electron beam generator to produce electrons which are accelerated into a dense metal to

produce X-rays. A linear Varian Accelerator in a Titan designed system is focused on to

a Tantalum alloy converter sheet to produce the x-rays.

Doses of 1 KGy and 3 KGy, divided into the two same groups as set in the Food

Technology Service, Inc. Protocol, were also used at the NCEBFR electron beam and x-

ray facility. One hundred oysters, 100 clams and 100 mussels used in this part of the

research were shucked and cleaned prior to being sent to the NCEBFR facility. The









oyster, clam and mussel shells were prepared with dosimeter envelopes following the

same procedure used in the Food Technology Service, Inc. Protocol (see pictures in

Appendix B). The dosimetry lab was then used to fill all of the envelopes with dosimeter

strips. The shell was then closed with a drop of Elmer's glue to prevent the shell from

opening during irradiation. All of the shells were then placed into Ziploc bags and placed

into a box with packing paper in-between the bags to protect the shells. The box of shells

was then shipped via FedEx to the NCEBFR facility. The shells were then run through

the electron beam till the desired dose was achieved as determined by the staff at

NCEBFR. After irradiation the shells were boxed up by the staff NCEBFR and shipped

via FedEx to the University of Florida. The shells were then taken to the FAST

doismetry lab and the dosimeter strips were read. The entire procedure was then repeated

for x-ray.

Gamma Irradiation Protocol

The gamma ray source for this research was Food Technology Service, Inc. facility

in Mulberry, FL. A Cobalt 60 (60Co) source was used at Food Technology to produce

gamma rays for large scale commercial irradiation. Food Technology was chosen over

smaller gamma units for its industrial scale because it could be used to irradiate all of the

oysters, clams and mussels at one time.

Two different doses, 1 KGy and 3 KGy were used in this research. These are the

doses that are currently being reviewed by the FDA for approval for use in seafood.

Oyster, clam and mussel shells (100 of each) were shucked and measured following the

Oyster, Clam and Mussel Measuring Protocol. Three dosimeter envelopes were attached

to each of the 300 shells using white carpenters glue from Elmer's Products Inc. of

Columbus, OH. One envelope was attached to the outside of each of the upper shell.









Another envelope was attached to the outside of the lower shell. The last envelope was

placed in-between the two shells. Each of the envelopes was filled with one dosimeter

strip at the FAST dosimetery lab. The shell was then closed with a drop of white

carpenters glue to prevent the shell from opening during irradiation. The shells were then

equally divided into two boxes. The boxes of shells were transplanted to Food Tech and

one box was irradiated at 1 KGy and the other at 3 KGy. After the desired dose was

received the shells were taken back to Gainesville via car and read at the FAST

dosimetery lab.

Statistics

All of the statistics for this research were performed using Microsoft Excel XP.

Paired t-test were performed on the entire external and internal dose data. All t-tests were

performed with a = 0.05. Linear regression models were used in all of the figures to

determine trend. An a = 0.05 was also used for all of the linear regression models as

well. Multiple linear regression models were performed in Microsoft Excel XP with the

addition XLSTAT on all of the data for figures. All of the multiple linear regression

models used a = 0.05 as well.















CHAPTER 4
RESULTS AND DISCUSSION

Oyster Irradiation with Electron Beam

The initial experiments for this research were performed with electron beam

irradiation of shucked oysters. Oysters were harvested on May 6, 2005 from approved

shellfish harvesting waters in Apalachicola, FL and irradiated by electron beam at

NCEBFR on June 8, 2005. The oysters were shucked, measured and loaded with

dosimeter strips before irradiation. After irradiation the dosimeter strips that were placed

on the top oyster shell, bottom oyster shell and in between the oyster shells were read

using spectrophotometery.

6
5.5
5
o4.5
4
0 3.5


2.5
2
1.5 *,


1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7
External Dose (Kgy)

Figure 4-1. The internal absorbed dose shucked oyster shells as compared to the external
absorbed dose of the top shell of shucked oysters after exposure to electron
beam at 1 kGy at NCEBFR (6/8/05). Solid line shows linear regression of
data with a=0.05 (y = 0.2774x + 1.307 R2 = 0.1814).









Figure 4-1 was created from the data in Table 10 (all Tables are located in

Appendix A). Data in Figure 4-1 show the internal absorbed dose compared to the

external top absorbed dose of the oyster shells irradiated at a dose of 1 kGy, as

determined by the staff of NCEBFR. The internal doses absorbed by the strips range

from 1.4 kGy to 3 kGy, have a median of 2.0 kGy and have a mean of 1.98 kGy.

External top absorbed doses range from 1.6 kGy to 4.1 kGy, have a median of 2.3 kGy

and have a mean of 2.46 kGy.

The mean dose absorbed was larger than the IkGy dose given as determined by

NCEBFR for both external and internal dosimeters. In most cases the internal doses are

smaller than the doses received by the top of the oyster shells. However, in six of the

thirty eight oysters irradiated at 1 kGy the internal absorbed dose is higher than the

external top absorbed dose. External top dose mean is 0.47 kGy larger than the internal

absorbed dose mean. Linear regression of the data shows a positive relationship between

external dose and internal dose. This positive relationship is as expected. A higher

external dose should produce a higher internal dose. The line does not fit the data well

with an R2 value of 0.1814. The line only has an 18% fit with R2 values ranging from 0

to 1. External dose and internal dose are statistically significantly different (P<0.05).

Figure 4-2 was created from the data in Table 10. Data in Figure 4-2 show the

internal absorbed dose compared to the external top absorbed dose of the oyster shells

irradiated at a dose of 3 kGy, as determined by the staff of NCEBFR using p0hotometric

technique. The internal doses absorbed by the strips range from 1.4 kGy to 5.3 kGy, have

a median of 3.9 kGy and have a mean of 3.63 kGy. External top absorbed doses range

from 1.9 kGy to 6.7 kGy, have a median of 4.3 kGy and have a mean of 4.18 kGy.










6
5.5






3*
S2.5 *

2
1.5
1
1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7
External Dose (Kgy)

Figure 4-2. The internal absorbed dose shucked oyster shells as compared to the external
absorbed dose of the top shell of shucked oysters after exposure at 3 kGy at
NCEBFR (6/8/05). Solid line shows linear regression of data with a=0.05 (y =
0.698x + 0.7163 R2 = 0.5105).

The mean dose absorbed was also larger than the 3 kGy dose given as determined

by NCEBFR for both external and internal dosimeters. In six of the sixty two oysters

irradiated at 3 kGy the internal absorbed dose is higher than the external top absorbed

dose. Having internal doses higher than the applied external doses is a concentration

phenomenon seen in both 1 kGy and 3 kGy oysters irradiated with electron beam. The

cause of this phenomenon is currently not known. External top dose mean is 0.51 kGy

larger than the internal absorbed dose mean. All of the oysters irradiated with electron

beam cover a larger range of doses than was to be expected. The external doses (applied

dose) cover a much larger range than we would expect. Not only does the internal dose

vary, but the external dose varies greatly as well. This issue is an undesirable effect of

electron beam. The doses in the oysters irradiated at 3 kGy are much more wide spread

than the doses of oysters irradiated at 1 kGy in Figure 4-1. Linear regression of the data










shows a positive relationship between internal dose and external dose. The regression

line for this data has a R2 value of 0.5105. External dose and internal dose are

statistically significantly different (P>0.05).

2
1.8
1.6

o
8 1 .4 -----------------------
a. 1.2 --
0
I-
ra 1









0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Mean Top Shell Thickness (cm)

Figure 4-3. Percent external top shell dose absorbed internally in the oyster shells as
compared to the mean thickness of the top shell of the oysters irradiated at
doses of lkGy and 3 kGy NCEBFR (6/8/05). Solid line shows linear
I 0.6 --^ -

= 0.4 *
0.2
0 ---------------------------------------




regression0 0.1 0.2 0.3 0.0..5 18460.6 0.7 0. 0.0226).

Figure 4-3 was created from the data in Table 3 and Table 10. Data in Figure 4-3(cm)

show Figure 4-3. Percent external top shell dose absorbed internally in the oyster shells as

~~compared to the mean thickness of the top shell of the oysters. For mean thickness of the
doses of IkGy and 3 kGy NCEBFR (6/8/05). Solid line shows linear
regression of data with a=0.05 (y = 0.1846x + 0.777 R2 = 0.0226).

Figure 4-3 was created from the data in Table 3 and Table 10. Data in Figure 4-3

show the percent external top shell dose absorbed internally in the oyster shells as

compared to the mean thickness of the top shell of the oysters. For mean thickness of the

top shell the range is 0.3 cm to 0.97 cm, the median is 0.46 cm and mean is 0.49 cm. The

percent external top shell dose absorbed internally range is 132% to 43%, the median is

90% and the mean is 86.8%.

Linear regression of this data shows a positive relationship between external dose

absorbed internally and mean shell thickness. It was expected that the percent external

top shell dose absorbed internally would decrease as the thickness increased, due to the









limited penetration of electron beam irradiation to penetrate thicker material as well as

thinner material. The data does not show this relationship. However, this line does fit

the data well with a R2 value of only 0.0226. Multiple linear regression of the data shows

no significant relationship between external dose absorbed internally and mean shell

thickness (P>0.05). It was expected that thickness would have a significant effect on the

internal absorbed dose. This may be a result in the porous nature of the shell. If we were

to measure thickness and dose on a microscopic level the results may differ. Also the

effects of thickness on dose may be overshadowed by a more important unknown

variable.

2
1.8
S1.6
S1.4
S1.2


o 0.8 -
E 06
e- *
-= 0.4 *
0.2

0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Top Shell Curvature

Figure 4-4. Percent external top shell dose absorbed internally in the oyster shells as
compared to the curvature of the top shell of the oysters irradiated at doses of
IkGy and 3 kGy NCEBFR (6/8/05). Solid line shows linear regression of data
with a=0.05 (y = 0.2084x + 0.8182 R2 = 0.0117).

Figure 4-4 was created from the data in Table 2 and Table 10. Data in Figure 4-4

show the percent external top shell dose absorbed internally in the oyster shells as

compared to the curvature of the top shell of the oysters. For curvature of the top shell









the range is 0.11 to 0.88, the median is 0.23 and mean is 0.24. The percent external top

shell dose absorbed internally range is 132% to 43%, the median is 90% and the mean is

86.8%.

The curvature of the oysters evaluated in this research did not vary as greatly as

first thought. The oysters appear to vary greatly in shape and size when examined by

hand. The curvatures of the assessed oysters are similar. Linear regression shows a

slight positive relationship between percentages of external dose absorbed internally and

top shell curvature. The line does not have a good fit however the R2 value is only

0.0117. Multiple linear regression models of the data show no statistically significant

relationship between curvature and percent of external dose absorbed internally (P>0.05).

It was expected that curvature would have some sort of an effect on percentage of

external dose absorbed internally. The lack of a significant effect may also be a result of

a different variable overshadowing the effects of curvature. Or curvature may not have

an effect on percentage of external dose being absorbed internally when irradiated with

electron beam.

Figure 4-5 was created from the data in Table 1 and Table 10. Data in Figure 4-5

show the percent external top shell dose absorbed internally in the oyster shells as

compared to the weight of the top shell of the oysters. For weight of the top shell the

range is 19.8g to 41.5g, the median is 27.6g and mean is 27.9g. The percent external top

shell dose absorbed internally range is 132% to 43%, the median is 90% and the mean is

86.8%.










2
1.8
1.6
1.4
0
0 1.2


E 0.8
o 1 t ,

S0.6 *
0.4
0.2
0
0 5 10 15 20 25 30 35 40 45
Top Shell Wt (g)

Figure 4-5. Percent external top shell dose absorbed internally in the oyster shells as
compared to the weight of the top shell of the oysters irradiated with electron
beam at doses of IkGy and 3 kGy NCEBFR (6/8/05). Solid line shows linear
regression of data with a=0.05 (y = -0.0032x + 0.9561 R2 = 0.0059).

The oysters assessed in this research covered a range weights. This can be seen in

the top shell weights presented in this graph. Percentage of external dose absorbed

internally is rather evenly dispersed between the weights assessed. Linear regression

shows a slight negative relationship between percentages of external dose absorbed

internally and top shell weight. The line does not have a good fit which is evident by the

R2 value of 0.0059. Multiple linear regression models show no statistically significant

difference between top shell weight and percentage of external dose absorbed internally

(P>0.05). There were no expectations for weight, but it was a factor that we hoped we

could use to produce a graphical model or an equation to predict the percentage of

external dose absorbed internally. However, for oysters irradiated with electron beam the

factors we investigated did not have enough statistical effect to produce a statically

significant model or equation.










Oyster Irradiation with X-Ray

The second set of experiments for this research was performed with x-ray

irradiation of shucked oysters. Oysters were harvested from approved harvesting waters

in Apalachicola, FL on May 6, 2005 and irradiated with x-ray at NCEBFR on June 26,

2005. The oysters were shucked, measured, irradiated with electron beam and loaded

with dosimeter strips that were placed on the top oyster shell, bottom oyster shell and in

between the oyster shells before irradiation with x-ray. After irradiation with x-ray the

dosimeter strips placed on the oysters were read with using spectrophotometery.

6
5.5
5
4.5
S4
o 3.5


S2.5
2 -

1.5 -
1I
1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
External Dose (Kgy)

Figure 4-6. The internal absorbed dose shucked oyster shells as compared to the external
absorbed dose of the top shell of shucked oysters after exposure to x-ray at 1
kGy at NCEBFR (6/26/05). Solid line shows linear regression of data with
a=0.05 (y = -0.1084x + 1.7874 R2 = 0.0141).

Figure 4-6 was created from the data in Table 11. Data in Figure 4-6 show the

internal absorbed dose compared to the external top absorbed dose of the oyster shells

irradiated by x-ray at a dose of 1 kGy, as determined by the staff of NCEBFR. The

internal doses absorbed by the strips range from 1.2 kGy to 2.6 kGy, have a median of









1.5 kGy and have a mean of 1.59 kGy. External top absorbed doses range from 1.3 kGy

to 3.0 kGy, have a median of 1.8 kGy and have a mean of 1.85 kGy.

The mean dose absorbed was larger than the IkGy dose given as determined by

NCEBFR for both external and internal dosimeters. Yet, the means are closer and the

data is more consistent than the data presented for electron beam in Figure 4-1. Six of the

thirty eight oysters irradiated with x-ray at 1 kGy exhibit an internal absorbed dose are

higher than the external top absorbed dose. External top dose mean is 0.26 kGy larger

than the internal absorbed dose mean. Linear regression of the data shows a very slight

negative relationship between external dose and internal dose. However, the fit of the

line to the data is not good with R2 value for the regression is 0.0041. External dose and

internal dose are statistically significantly different (P>0.05). It was expected that these

doses would be different due to x-ray's lower energy and penetration.

Figure 4-7 was created from the data in Table 11. Data in Figure 4-7 show the

internal absorbed dose compared to the external top absorbed dose of the oyster shells

irradiated by x-ray at a dose of 3 kGy, as determined by the staff of NCEBFR. The

internal doses absorbed by the strips range from 1.2 kGy to 6.9 kGy, have a median of

3.8 kGy and have a mean of 3.82 kGy. External top absorbed doses range from 1.4 kGy

to 6.9 kGy, have a median of 4.2 kGy and have a mean of 4.12 kGy.

The mean dose absorbed was also larger than the 3 kGy dose given as determined

by NCEBFR for both external and internal doses. In eight of the sixty two oysters

irradiated at 3 kGy the internal absorbed dose is higher than the external top absorbed

dose. As with electron beam this concentration phenomenon is seen at doses of 1 kGy

and 3 kGy. External top dose mean is 0.31 kGy larger than the internal absorbed dose










mean. Linear regression of the data shows a positive relationship between internal dose

and external dose at a 95% confidence interval and a good data fit with a R2 value of

0.6808. The doses in the oysters irradiated at 3 kGy are much more wide spread than the

doses of oysters irradiated at 1 kGy. The oysters irradiated at 3 kGy with x-ray (Figure 4-

7) and 3 kGy with electron beam (Figure 4-2) are more similar to each other than the

oysters irradiated at IkGy x-ray (Figure 4-6) and 1 kGy with electron beam (Figure 4-1).

External doses and internal doses of oysters irradiated with x-ray at 3 kGy are statistically

significantly different (P<0.05).


7 A
6.5 5
6 -
5.5
i 5 A
SA A
S4.5
0 tt A
S3.5 A
3
2.5 -
A A

1.5

1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7
External Dose (Kgy)

Figure 4-7. The internal absorbed dose of shucked oyster shells as compared to the
external absorbed dose of the top shell of shucked oysters after exposure to x-
ray at 3 kGy at NCEBFR (6/26/05). Solid line shows linear regression of data
with a=0.05 (y = 0.9596x 0.1584 R2 = 0.6808).

Figure 4-8 was created from the data in Table 3 and Table 11. Data in Figure 4-8

show the percent external top shell x-ray dose absorbed internally in the oyster shells as

compared to the mean thickness of the top shell of the oysters. For mean thickness of the

top shell the range is 0.3 cm to 0.97 cm, the median is 0.46 cm and mean is 0.49 cm. The









percent external top shell dose absorbed internally range is 50% to 123%, the median is

90% and the mean is 91%.

2
1.8
1.6
w 1.4
A



0.8
0.6
0.4
0.2
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Mean Top Shell Thickness (cm)

Figure 4-8. Percent external top shell dose absorbed internally in the oyster shells as
compared to the mean thickness of the top shell of the oysters irradiated at
doses of IkGy and 3 kGy with x-ray NCEBFR (6/26/05). Solid line shows
linear regression of data with a=0.05 (y = -0.0916x + 0.9566 R2 = 0.0041).

The data for percentage of external top shell dose absorbed internally is more

tightly grouped for oysters irradiated with electron beam (Figure 4-3) than oysters

irradiated with x-ray (Figure 4-8). Linear regression of the data shows a slight negative

relationship between the percentage of external dose absorbed internally and mean top

shell thickness at a 95% confidence interval. The line for this data does not have a good

fit with a R2 value of 0.0041. Multiple linear regression models show no statistically

significant relationship (P>0.05) between the external doses absorbed internally and

mean top shell thickness of oysters treated with x-ray. As with electron beam this was not

expected.










2
1.8
S1.6
8 1.4





I 0.6 A
0.4
0.2
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Top Shell Curvature

Figure 4-9. Percent external top shell dose absorbed internally in the oyster shells as
compared to the curvature of the top shell of the oysters irradiated at doses of
IkGy and 3 kGy with x-ray at NCEBFR (6/26/05). Solid line shows linear
regression of data with a=0.05 (y = -0.3866x + 1.004 R2 = 0.0297).

Figure 4-9 was created from the data in Table 2 and Table 11. Data in Figure 4-9

show the percent external top shell x-ray dose absorbed internally in the oyster shells as

compared to the curvature of the top shell of the oysters. For curvature of the top shell

the data range is 0.11 to 0.88, the median is 0.23 and mean is 0.24. The percent external

top shell dose absorbed internally range is 50% to 123%, the median is 90% and the

mean is 91%.

The data from electron beam (Figure 4-4) and x-ray (Figure 4-9) is also very

similar for curvature. The data for electron beam appears to be slightly more tightly

grouped than the data for x-ray. A slight negative relationship is shown between

percentage of external dose absorbed internally and top shell curvature with linear

regression of at a confidence interval of 95%. However, with a R2 value of 0.0297 the

line does not fit the data well. Multiple linear regression models of this data show no










statistically significant relationship between percentage of external dose absorbed

internally and top shell curvature at a (P<0.05). It was expected that there would be some

effect of curvature on percentage of external dose absorbed internally. However,

curvature may be overshadowed by another factor or just not have an effect at all.

Figure 4-10 was created from the data in Table 1 and Table 11. Data in Figure 4-

10 show the percent external top shell dose absorbed internally in the oyster shells as

compared to the weight of the top shell of the oysters. For weight of the top shell the

range is 19.8g to 41.5g, the median is 27.6g and mean is 27.9g. The percent external top

shell dose absorbed internally range is 50% to 123%, the median is 90% and the mean is

91%.


2 -
1.8
A
1.6
A 1.4
o A
Qo 1 .2 A
CL t A
0 AAA AA A
1 4A
A AA A A
E 0.8 A A7 A

0.6 A
0.4
0.2
0
0 5 10 15 20 25 30 35 40 45
Top Shell Wt (g)

Figure 4-10. Percent external top shell dose absorbed internally in the oyster shells as
compared to the weight of the top shell of the oysters irradiated at doses of
IkGy and 3 kGy with x-ray NCEBFR (6/26/05). Solid line shows linear
regression of data with a=0.05 (y = 0.0094x + 0.65 R2 = 0.0383).

Linear regression models of the data show a slight negative relationship between

percentages of external dose absorbed internally and top shell weight. The line does not









have a good fit however the R2 value is only 0.0059. No statically significant

relationship (P>0.05) exists between external dose absorbed internally and top shell

weight in multiple linear regression models. None of the factors assessed for oysters

irradiated with x-ray have a statically significant effect on percentage of external dose

absorbed internally.

Oyster Irradiation with Gamma

The third set of experiments for this research was performed with 60Co gamma

irradiation of shucked oysters. Oysters were harvested on May 6, 2005 from approved

harvesting waters in Apalachicola, irradiated with gamma at Food Technology Inc. on

July 6, 2005. The oysters were shucked, measured, irradiated with electron beam,

irradiated with x-ray and loaded with dosimeter strips before irradiation with gamma.

After irradiation with gamma the dosimeter strips placed on the top oyster shell, bottom

oyster shell and in between the oyster shells were read using spectrophotometery.

Figure 4-11 was created from data in Table 12. Data in Figure 4-11 show the

internal absorbed dose compared to the external top absorbed dose of the oyster shells

irradiated by gamma at a dose of 1 kGy, as determined by the staff of Food Technology

Inc. The internal doses range from 1.2 kGy to 2.3 kGy, have a median of 1.8 kGy and

have a mean of 1.77 kGy. External top absorbed doses range from 1.3 kGy to 3.1 kGy,

have a median of 2.0 kGy and have a mean of 1.98 kGy.

The range of data for gamma is smaller than the range for electron beam or x-ray.

The mean dose absorbed was larger than the IkGy dose given as determined by Food

Technology Inc. for both external and internal dosimeters. For gamma the means are

closer and the data is more consistent than the data presented for electron beam (Figure 4-

1) or the data presented for x-ray in (Figure 4-6). However, the external doses and










internal doses are statistically significantly different (P>0.05). The internal absorbed

dose is not higher than the external top absorbed dose for any of the thirty eight oysters

irradiated with gamma at 1 kGy. External top dose mean is 0.26 kGy larger than the

internal absorbed dose mean. Linear regression of this data shows a positive relationship

between external doses and internal doses at a 95% confidence interval.

6
5.5
5
c 4.5
4
0 3.5


2.5
2 -
1.5


1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
External Dose (Kgy)

Figure 4-11. The internal absorbed dose shucked oyster shells as compared to the
external absorbed dose of the top shell of shucked oysters after exposure to
gamma at 1 kGy at Food Technology Inc. (7/6/05). Solid line shows linear
regression of data with a=0.05 (y = 0.6965x + 0.3874 R2 = 0.8077).

Figure 4-12 was created from data in Table 12. Data in Figure 4-12 show the

internal absorbed dose compared to the external top absorbed dose of the oyster shells

irradiated by gamma at a dose of 3 kGy, as determined by the staff of Food Technology

Inc. The internal doses absorbed range from 1.8 kGy to 5.2 kGy, have a median of 3.9

kGy and have a mean of 3.95 kGy. External top absorbed doses range from 1.8 kGy to

5.5 kGy, have a median of 4.2 kGy and have a mean of 4.13 kGy.










6
5.5
5
S4.5








1.5

1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
External Dose (Kgy)

Figure 4-12. The internal absorbed dose of shucked oyster shells as compared to the
external absorbed dose of the top shell of shucked oysters after exposure to
gamma at 3 kGy at Food Technology Inc. (7/6/05). Solid line shows linear
regression of data with a=0.05 (y = 0.9254x + 0.1138 R2 = 0.9372).

The data in Figure 4-12 follows the same layout as the electron beam (Figure 4-2)

and the x-ray (Figure 4-7), but is more uniform and consistent. However, the external

doses and internal doses are statistically significantly different with a confidence level of

95%. Zero of the oysters irradiated with gamma at 3 kGy exhibit a internal absorbed

dose higher than the external top absorbed dose. Gamma does not exhibit the

concentration phenomenon that affects electron beam and x-ray. External top dose mean

is 0.18 kGy larger than the internal absorbed dose mean. Linear regression of the data

shows a positive relationship between external dose and internal dose. With a R2 value of

0.9372 the regression line is almost a perfect fit. The data for gamma is more tightly

grouped than the data for electron beam and x-ray. Gamma produces more consistent

results than electron beam or x-ray in oysters.










2
1.8
0 1.6
? 1.4
o
Q 1.2
E 1
x 0.8 -. *
0.6
0.4
0.2
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Mean Top Shell Thickness (cm)

Figure 4-13. Percent external top shell dose absorbed internally in the oyster shells as
compared to the mean thickness of the top shell of the oysters irradiated at
doses of 1 kGy and 3 kGy with gamma at Food Technology Inc. (7/6/05).
Solid line shows linear regression of data with a=0.05 (y = -0.0608x + 0.9641
R2 0.0176).

Figure 4-13was created from data in Table 3 and Table 12. Data in Figure 4-13

show the percent external top shell gamma dose absorbed internally in the oyster shells as

compared to the mean thickness of the top shell of the oysters. For mean thickness of the

top shell the range is 0.3 cm to 0.97 cm, the median is 0.46 cm and mean is 0.49 cm. The

percent external top shell dose absorbed internally range is 74% to 100%, the median is

95% and the mean is 93%.

The shell thickness does not appear to affect the dose received in Figure 4-13. Data

in Figure 4-13. are more tightly grouped than the data for electron beam (Figure 4-3) and

the data for x-ray (Figure 4-8). A slight negative relationship exist between percentage of

external dose absorbed internally and mean top shell thickness when linear regression

models are ran with a 95% confidence interval. The line is not a good fit for the data









with a R2 value of only 0.0176. Multiple linear regression models show no statistically

significant relationship (P>0.05) between mean top shell thickness and percentage of

external dose absorbed internally. It was expected that mean top shell thickness would

have a negative relationship to percentage of external dose absorbed internally. The lack

of a relationship may be caused by the use of macro measurements instead of micro

measurements or thickness may be overshadowed by other unknown factors. Oyster top

shell thickness does not have a statistically significant relationship (P>0.05) to percentage

of external dose absorbed internally for any of the three irradiation sources tested.

2
1.8
1.6
0)
0 1.4-
a 1.2

'71







0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
S0.4 .
S0.2 -

0 -
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Top Shell Curvature

Figure 4-14. Percent external top shell dose absorbed internally in the oyster shells as
compared to the curvature of the top shell of the oysters irradiated at doses of
tkGy and 3 kGy with gamma at Food Technology Inc. (7/6/05). Solid line
shows linear regression of data with a=0.05 (y = -0.0055x + 0.9354 R2 = 6E-
05).

Figure 4-14 was created from data in Table 2 and Table 12. Data in Figure 4-14

show the percent external top shell gamma dose absorbed internally in the oyster shells as

compared to the curvature of the top shell of the oysters. For curvature of the top shell

the range is 0.11 to 0.88, the median is 0.23 and mean is 0.24. The percent external top










shell dose absorbed internally for gamma irradiation range is 74% to 100%, the median is

95% and the mean is 93%.

The data for the gamma (Figure 4-14) is more tightly grouped than the data for

electron beam (Figure 4-4) or the data for x-ray (Figure 4-9). Linear regression at a 95%

confidence interval shows an extremely small negative relationship between the

percentage of external dose absorbed internally and top shell curvature. However, the fit

of the line is horrible with a R2 value of 0.00006. Multiple linear regression models of

the data show no statistically significant relationship (P>0.05) between percentage of

external dose absorbed internally and top shell curvature. As with electron beam and x-

ray, curvature does not have a statistically significant (P>0.05) effect on the percentage of

external dose absorbed internally in oysters irradiated with gamma.

2 -
1.8
1.6
a 1.4
1.2
1 .
E 0.8
0.6
0.4
0.2
0
0 5 10 15 20 25 30 35 40 45
Top Shell Wt (g)

Figure 4-15. Percent external top shell dose absorbed internally in the oyster shells as
compared to the weight of the top shell of the oysters irradiated at doses of
IkGy and 3 kGy with gamma Food Technology Inc. (7/6/05). Solid line
shows linear regression of data with a=0.05 (y = -0.0024x + 1.0004 R2
0.0241).









Figure 4-15 was created from data in Table 1 and Table 12. Data in Figure 4-15

show the percent external top shell dose absorbed internally in the oyster shells as

compared to the weight of the top shell of the oysters. For weight of the top shell the

range is 19.8g to 41.5g, the median is 27.6g and mean is 27.9g.

The percent external top shell dose absorbed internally range is 74% to 100%, the

median is 95% and the mean is 93%.

Percentage of external dose absorbed internally is rather evenly dispersed between

the weights assessed. Linear regression shows a slight negative relationship between

percentages of external dose absorbed internally and top shell weight at a 95%

confidence interval. The line does not have a good fit however the R2 value is only

0.0241. No significant relationship exists between external dose absorbed internally and

top shell weight in multiple linear regression models (P>0.05). Top shell weight does not

have a statistically significant (P>0.05) effect on percentage of external dose absorbed

internally in any of the three irradiation sources examined.

The external doses and internal doses are statistically significantly different

(P<0.05) in oysters irradiated with electron beam, x-ray and gamma at doses of 1 kGy

and 3 kGy. This is to be expected due to the barrier effect of the oyster shell against

irradiation. Top shell thickness, curvature and weight all have no significant effect on

percentage of external dose absorbed internally for oysters irradiated at 1 kGy and 3 kGy

with electron beam, x-ray and gamma. This was not expected, but as discussed above

this may be an effect of macro measurement instead of micro measurements or these

factors may be overshadowed by a more important unknown factor. Of the three sources

the data for gamma is most tightly grouped. Oysters irradiated with gamma also have









smaller ranges of data than electron beam and x-ray do. Gamma does not exhibit the

concentration phenomenon that is seen in electron beam and x-ray. Because of these

reasons gamma is the most promising irradiation source for irradiating oysters on a large

scale.

Further experiments need to be performed. Large scale experiments with pallets of

hundreds of bushels of oysters would provide the data needed to examine how effective

gamma is in industrial production. Further experiment with electron beam and x-ray are

also needed. Electron beam and x-ray may be more promising for half shell oysters.

Further research may add to the knowledge and direct how electron beam, x-ray and

gamma can be used to efficiently irradiate oysters.

Clam Irradiation with Electron Beam

Electron beam was used to irradiate clams at NCEBFR as well. Clams were

harvested on May 11, 2005 from Cedar Key and irradiated with electron beam on June 8,

2005. The clams were shucked, measured and loaded with dosimeter strips during the

before irradiation. After irradiation the dosimeter strips placed on the top clam shell,

bottom clam shell and in between the clam shells were read using spectrophotometery.

Figure 4-16 was created using the data in Table 13. Data in Figure 4-16 show the

internal absorbed dose compared to the external top absorbed dose of the clam shells

irradiated at a dose of 1 kGy, as determined by the staff of NCEBFR. The internal doses

absorbed by the strips range from 1.2 kGy to 2 kGy, have a median of 1.7 kGy and have a

mean of 1.70 kGy. External top absorbed doses range from 1.5 kGy to 3.1 kGy, have a

median of 2.1 kGy and have a mean of 2.12 kGy.










6
5.5
5
4.5
o 4
o 3.5
3
2.5
2
1.5
1
1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
External Dose (Kgy)

Figure 4-16. The internal absorbed dose shucked clam shells as compared to the external
absorbed dose of the top shell of shucked clams after exposure to electron
beam at 1 kGy at NCEBFR (6/8/05). Solid line shows linear regression of
data with a=0.05 (y = 0.0405x + 1.6096 R2 = 0.0061).

The mean dose absorbed was larger than the IkGy dose given as determined by

NCEBFR for both external and internal dosimeters. In most cases the internal doses are

smaller than the doses received by the top of the clam shells. However, in three of the

forty five clams irradiated at 1 kGy the internal absorbed dose is higher than the external

top absorbed dose. The external doses and internal doses are statistically significantly

different (P>0.05). External top dose mean is 0.42 kGy larger than the internal absorbed

dose mean. Linear regression of the data at a 95% confidence interval shows a very

small positive relationship exist between external doses and internal doses. However the

fit of line to the data is not good with a R2 of 0.0061. The data for clams irradiated with

electron beam at 1 kGy are more tightly grouped than the data for oysters irradiated with

electron beam at 1 kGy.










6
5.5
5
i 4.5
4






1.5 *
2-
1.5 -------------------------
1
1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
External Dose (Kgy)

Figure 4-17. The internal absorbed dose shucked clam shells as compared to the external
absorbed dose of the top shell of shucked clams after exposure at 3 kGy at
NCEBFR (6/8/05). Solid line shows linear regression of data with a=0.05 (y
= 0.9134x + 0.152 R2 = 0.8344).

Figure 4-17 was created using the data in Table 13. Data in Figure 4-17 show the

internal absorbed dose compared to the external top absorbed dose of the clam shells

irradiated at a dose of 3 kGy, as determined by the staff of NCEBFR. The internal doses

absorbed by the strips range from 1.5 kGy to 4.2 kGy, have a median of 3.7 kGy and

have a mean of 3.50 kGy. External top absorbed doses range from 1.8 kGy to 4.6 kGy,

have a median of 3.8 kGy and have a mean of 3.78 kGy.

The mean dose absorbed was also larger than the 3 kGy dose given as determined

by NCEBFR for both external and internal doses. In nine of the fifty five clams

irradiated at 3 kGy the internal absorbed dose is higher than the external top absorbed

dose. The concentration phenomenon is seen in clams irradiated with electron beam as

well as oysters. However, the external doses and internal doses are statistically

significantly different (P<0.05). External top dose mean is 0.29 kGy larger than the










internal absorbed dose mean. Linear regression of the data shows a positive relationship

between external doses and internal doses with a 95% confidence interval. The line is a

good fit with a R2 value of 0.3158. The tighter grouping of data for clams irradiated with

electron beam than data for oysters irradiated with electron beam may be a result of the

more uniform shape and structure of the clams.

Figure 4-18 was created using the data in Table 6 and Table 13. Data in Figure 4-

18 show the percent external top shell dose absorbed internally in the clam shells as

compared to the mean thickness of the top shell of the clams. For mean thickness of the

top shell the range is 0.26 cm to 0.33 cm, the median is 0.29 cm and mean is 0.29 cm.

The percent external top shell dose absorbed internally range is 50% to 125%, the median

is 92% and the mean is 88%.

1.5
1.4
1.3
1.2 -
0 1.1 *
U,
o 1
S0.9
cc
c 0.8
S0.7
wL 0.6 -
S0.5-'
E 0.4
0.3
0.2
0.1
0 -
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Mean Top Shell Thickness (cm)

Figure 4-18. Percent external top shell dose absorbed internally in the clam shells as
compared to the mean thickness of the top shell of the clams irradiated with
electron beam at doses of IkGy and 3 kGy NCEBFR (6/8/05). Solid line
shows linear regression of data with a=0.05 (y = 0.217x + 0.8137 R2
0.0005).









Linear regression of the data shows a small positive relationship between the

percentage of external dose absorbed internally and the mean top shell thickness at a 95%

confidence interval. However, the line is not a good fit with a R2 value of only 0.0005.

The percent of external top shell dose absorbed internally covers a range of 75%. The

percentages of doses received internally from the electron beam are not very uniform.

Multiple linear regression models shows no significant relationship between the percent

of external top shell dose absorbed internally and the mean top shell thickness (P<0.05).

As with oysters, thickness does not have a statistically significant effect (P>0.05) on the

percentage of external dose absorbed internally in clams irradiated with electron beam.

Figure 4-19 was created using the data in Table 5 and Table 13. Data in Figure 4-

19 show the percent external top shell dose absorbed internally in the clam shells as

compared to the curvature of the top shell of the clams. For curvature of the top shell the

range is 0.26 to 0.39, the median is 0.33 and mean is 0.33. The percent external top shell

dose absorbed internally range is 50% to 125%, the median is 92% and the mean is 88%.

The curvatures of the clams analyzed in this research are very uniform. A negative

relationship exists, at confidence interval of 95%, between the percentage of external

dose absorbed internally and the top shell curvature when linear regression is applied to

the data. However, with an R2 value of 0.0237 the line is not a good fit. In addition,

multiple linear regression models of the data show no statistically significant relationship

(P>0.05) between the percentage of external dose absorbed internally and the top shell

curvature. Like oysters top shell curvature was expected to a significant effect on the

percentage of external dose absorbed internally. The unexpected result may be an effect







44


of measuring techniques or a result of other factors overshadowing the effect of curvature

on the percentage of external dose absorbed internally.

1.5
1.4
1.3

1.2
0.
08

0 0.9 *
C 0.8
S 0.7
lU 0 .6 ---------S----------------

E 0 .4 ----------------------------
H 0 .3 ----------------------------
0.2
0.1
0 ------------------------------------
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Top Shell Curvature


Figure 4-19. Percent external top shell dose absorbed internally in the clam shells as
compared to the curvature of the top shell of the clams irradiated with electron
beam at doses of IkGy and 3 kGy NCEBFR (6/8/05). Solid line shows linear
regression of data with a=0.05 (y = -1.1461x + 1.2569 R2 = 0.0237).

Figure 4-20 was created using the data in Table 7 and Table 13. Data in Figure 4-

20 show the percent external top shell dose absorbed internally in the clam shells as

compared to the weight of the top shell of the clams. For weight of the top shell the

range is 10.0g to 20.6g, the median is 13.0g and mean is 13.9g.

The percent external top shell dose absorbed internally range is 50% to 125%, the

median is 92% and the mean is 88%.

Linear regression shows a positive relationship between percentages of external

dose absorbed internally and top shell weight at a 95% confidence interval. The line does

not have a good fit however the R2 value is only 0.0005. No statistically significant

relationship (P>0.05) exists between external dose absorbed internally and top shell










weight in multiple linear regression models with a 95% confidence level. Like thickness

and curvature, weight is not a statistically significant factor in determining the percentage

of external dose absorbed internally in clams irradiated with electron beam. Other factors

or thickness, curvature and weight must be examined in order to determine the factors

that effect percentage of external dose absorbed internally.

1.5
1.4
1.3
1.2
0 1.1
a 0.9 4

S0.8
S0.7 -
wL 0.6
S0.5-
E 0.4
0.3
0.2
0.1
0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
Top Shell Weight (g)

Figure 4-20. Percent external top shell dose absorbed internally in the clam shells as
compared to the weight of the top shell of the clam irradiated at doses of IkGy
and 3 kGy with electron beam NCEBFR (6/8/05). Solid line shows linear
regression of data with a=0.05 (y = 0.217x + 0.8137 R2 = 0.0005).

Clam Irradiation with X-ray

Shucked clams were also irradiated with x-ray for this research. Clams were

harvested on May 11, 2005 from Cedar Key, irradiated with x-ray at NCEBFR on June

26, 2005. The clams were shucked, measured, irradiated with electron beam and loaded

with dosimeter strips before irradiation with x-ray. After irradiation with x-ray the

dosimeter strips placed on the top clam shell, bottom clam shell and in between the clam

shells were read using spectrophotometery.










6
5.5
5
S4.5
4
S3.5
3
) 2.5 t
C A A A A
2 AA AA A A A
1.5 --A


1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
External Dose (Kgy)

Figure 4-21. The internal absorbed dose shucked clam shells as compared to the external
absorbed dose of the top shell of shucked clams after exposure to x-ray at 1
kGy at NCEBFR (6/26/05). Solid line shows linear regression of data with
a=0.05 (y = 0.3976x + 1.0481 R2 = 0.3738).

Figure 4-21 was created from the data in Table 14. Data in Figure 4-21 show the

internal absorbed dose compared to the external top absorbed dose of the clam shells

irradiated by x-ray at a dose of 1 kGy, as determined by the staff of NCEBFR. The doses

absorbed internally range from 1.2 kGy to 3.0 kGy, have a median of 1.9 kGy and have a

mean of 1.9 kGy. External top absorbed doses range from 1.2 kGy to 4.2 kGy, have a

median of 2.2 kGy and have a mean of 2.23 kGy.

The mean dose absorbed was larger than the IkGy dose given as determined by

NCEBFR for both external and internal dosimeters. External doses and internal doses of

clams irradiated at 1 kGy with x-ray are statistically significantly different (P<0.05). In

eight of the forty five clams irradiated with x-ray at 1 kGy the internal absorbed dose are

higher than the external top absorbed dose. External top dose mean is 0.33 kGy larger










than the internal absorbed dose mean. External dose and internal dose have a positive

relationship in linear regression models with a R2 value equal to 0.3738.

6 -
5.5 -


i 4.5
A A

o 3.5 -
3 3
S2.5
2
A
1.5
1
1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
External Dose (Kgy)

Figure 4-22. The internal absorbed dose of shucked clam shells as compared to the
external absorbed dose of the top shell of shucked clams after exposure to x-
ray at 3 kGy at NCEBFR (6/26/05). Solid line shows linear regression of data
with a=0.05 (y = 0.6603x + 1.2588 R2 = 0.5929).

Figure 4-22 was created from the data in Table 14. Data in Figure 4-22 show the

internal absorbed dose compared to the external top absorbed dose of the clam shells

irradiated by x-ray at a dose of 3 kGy, as determined by the staff of NCEBFR. The

internal doses absorbed range from 1.8 kGy to 5.4 kGy, have a median of 4.0 kGy and

have a mean of 4.05 kGy. External top absorbed doses range from 1.7 kGy to 6.3 kGy,

have a median of 4.3 kGy and have a mean of 4.27 kGy.

The mean dose absorbed was also larger than the 3 kGy dose given as determined

by NCEBFR for both external and internal doses by more than IkGy. In nine of the fifty

five clams irradiated at 3 kGy the internal absorbed dose is higher than the external top

absorbed dose. The external doses and internal doses are statistically significantly









different (P<0.05). External top dose mean is 0.22 kGy larger than the internal absorbed

dose mean. Linear regression of the data shows a positive relationship between external

dose and internal dose at a 95% confidence interval. Data for clams irradiated with x-ray

are more tightly grouped than oysters irradiated with x-ray. As discussed above the farm

raised clams are more uniform shell and are more similar to each other than the wild

oysters.

Figure 4-23 was created from the data in Table 6 and Table 14. Data in Figure 4-

23 show the percent external top shell x-ray dose absorbed internally in the clam shells as

compared to the mean thickness of the top shell of the clams. For mean thickness of the

top shell the range is 0.26 cm to 0.33 cm, the median is 0.29 cm and mean is 0.29 cm.

The percent external top shell dose absorbed internally range is 56% to 163%, the median

is 94% and the mean is 93%.

The data in Figure 4-23 are also very similar to the data found Figure 4-18. Both x-

ray and electron beam have similar spreads of percentage of external dose absorbed

internally. Linear regression of the data shows a positive relationship between the

percentage of external dose absorbed internally and the mean top shell thickness at a 95%

confidence interval. However, the R2 value for this data is only 0.0064 meaning that the

line is not a good fit for the data. Multiple linear regression models show no statistically

significant relationship (P>0.05) between percentage of external dose absorbed internally

and the mean top shell thickness. It was expected that thickness would have a negative

relationship to percentage of external dose absorbed internally. The lack of a relationship

here may be due to the small range of thicknesses examined.







49


1.5
1.4
S1.3
1- .2 -A A
1.1
0 1 A ,4.
0.9 A
E 0.8 AIA
0.7 i A
L. 0.6 -A
0.5
E 0.4
0.3
-c 0.2
0.1
0
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Mean Top Shell Thickness (cm)

Figure 4-23. Percent external top shell dose absorbed internally in the clam shells as
compared to the mean thickness of the top shell of the clams irradiated at
doses of IkGy and 3 kGy with x-ray NCEBFR (6/26/05). Solid line shows
linear regression of data with a=0.05 (y = 0.7114x + 0.7226 R2 = 0.0064v).

Figure 4-24 was created from the data in Table 5 and Table 14. Data in Figure 4-

24 show the percent external top shell x-ray dose absorbed internally in the clam shells as

compared to the curvature of the top shell of the clams. For curvature of the top shell the

range is 0.26 to 0.39, the median is 0.33 and mean is 0.33. The percent external top shell

dose absorbed internally range from 70% to 117%, have a median of 98% and have a

mean of 96%.

Curvatures of clam shell examined in this research are very uniform. The clam

shell curvatures are less diverse than the oyster shells. A negative relationship is shown

between percentage of external dose absorbed internally and top shell curvature in linear

regression models with a confidence interval of 95% and a R2 value of 0.0006. However,

multiple linear regression models show no statistically significant relationship (P>0.05)

between percentage of external dose absorbed internally and top shell curvature.










1.5
1.4
^ 1.3
1.2 -
S1.1 AAA
O 1
0.8
0.9


W 0.6 A-
L, 0.6 -"At
0.5
E 0.4
S0.3-
0.2
0.1
0 -- I i i i i ---I
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Top Shell Curvature

Figure 4-24. Percent external top shell dose absorbed internally in the clam shells as
compared to the curvature of the top shell of the clams irradiated at doses of
IkGy and 3 kGy with x-ray at NCEBFR (6/26/05). Solid line shows linear
regression of data with a=0.05 (y = -0.1797x + 0.9903 R2 = 0.0006).

Figure 4-25 was created from the data in Table 4 and Table 14. Data in Figure 4-

25 show the percent external top shell dose absorbed internally in the clam shells as

compared to the weight of the top shell of the clams. For weight of the top shell the

range is 10.0g to 20.6g, the median is 13.0g and mean is 13.9g.

The percent external top shell dose absorbed internally range is 70% to 117%, the

median is 98% and the mean is 96%.

Linear regression shows a positive relationship between percentages of external

dose absorbed internally and top shell weight at a 95% confidence interval. The line does

not have a good fit however the R2 value is only 0.0064. No statistically significant

relationship (P>0.05) exists between external dose absorbed internally and top shell

weight in multiple linear regression model. As with electron beam irradiated clams, x-

ray irradiated clams are not significantly affected by any of the factors we assessed.










Further experiments examining a larger range thicknesses, curvatures and weight may

provide different results. Measuring the shells microscopically may also provide

different results.

1.5
1.4
1.3
1.2 -

1 1. 5A 6A I 1 A
S0.9 A A
E 0.8 A
0.7 -- A
LJ 0.6- A A A
0.5
E 0.4
-* 0.3
0.2
0.1

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
Top Shell Weight (g)

Figure 4-25. Percent external top shell dose absorbed internally in the clam shells as
compared to the weight of the top shell of the clam irradiated at doses of IkGy
and 3 kGy with x-ray NCEBFR (6/26/05). Solid line shows linear regression
of data with a=0.05 (y = 0.7114x + 0.7226 R2 = 0.0064).

Clam Irradiation with Gamma

A 60Co gamma source was also used in the irradiation of shucked clams. Clams

were harvested on May 11, 2005 from Cedar Key, irradiated with gamma at Food

Technology Inc. on July 6, 2005. The clams were shucked, measured, irradiated with

electron beam, irradiated with x-ray and loaded with dosimeter strips before irradiation

with gamma. After irradiation with gamma the dosimeter strips placed on the top clam

shell, bottom clam shell and in between the clam shells were read using

spectrophotometery.










Figure 4-26 was created from the data in Table 15. Data in Figure 4-26 show the

internal absorbed dose compared to the external top absorbed dose of the clam shells

irradiated by gamma at a dose of 1 kGy, as determined by the staff of Food Technology

Inc.. The internal doses range from 1.4 kGy to 3.1 kGy, have a median of 1.8 kGy and

have a mean of 1.88 kGy. External top absorbed doses range from 1.5 kGy to 3.3 kGy,

have a median of 2.0 kGy and have a mean of 2.09 kGy.

6
5.5
5
4.5
4
0 3.5
E 3
-S 2.5


1.5


1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
External Dose (Kgy)

Figure 4-26. The internal absorbed dose shucked clam shells as compared to the external
absorbed dose of the top shell of shucked clams after exposure to gamma at 1
kGy at Food Technology Inc. (7/6/05). Solid line shows linear regression of
data with a=0.05 (y = 0.6135x + 0.6042 R2 = 0.6179).

The mean dose absorbed was larger than the IkGy dose given as determined by

Food Technology Inc. for both external and internal dosimeters. For gamma the means

are closer than the means for electron beam or x-ray. The external doses and internal

doses are statistically significantly different (P<0.05) for clams irradiated at 1 kGy with

gammas. For only one of the forty five clams irradiated with gamma at 1 kGy the internal

absorbed dose is higher than the external top absorbed dose. External top dose mean is






53


0.21 kGy larger than the internal absorbed dose mean. Linear regression of the data

shows a positive relationship between external dose and internal dose at a 95%

confidence interval. The regression line is also a good fit with a R2 value of 0.6179.

Figure 4-27 was created from the data in Table 15. Data in Figure 4-27 show the

internal absorbed dose compared to the external top absorbed dose of the clam shells

irradiated by gamma at a dose of 3 kGy, as determined by the staff of Food Technology

Inc. The internal doses absorbed range from 1.5 kGy to 5.1 kGy, have a median of 4.3

kGy and have a mean of 4.24 kGy. External top absorbed doses range from 1.7 kGy to

5.2 kGy, have a median of 4.6 kGy and have a mean of 4.46 kGy.

6 -
5.5


3.5



I 3 -
S4.5

2 -

1.5
1
1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
External Dose (Kgy)

Figure 4-27. The internal absorbed dose of shucked clam shells as compared to the
external absorbed dose of the top shell of shucked clams after exposure to
gamma at 3 kGy at Food Technology Inc. (7/6/05). Solid line shows linear
regression of data with a=0.05 (y = 0.9134x + 0.152 R2 = 0.8344).

The external doses and internal doses are statistically significantly different

(P<0.05). None of the clams irradiated with gammas at 3 kGy have a internal dose higher

than the external dose. As with oysters gamma does not show the effects of a









concentration phenomenon. The external top dose mean is 0.22 kGy larger than the

internal absorbed dose mean. Data for clams irradiated with gamma are more tightly

grouped than data for clams irradiated with electron beam and x-ray. A positive

relationship between external dose and internal dose is shown by linear regression of the

data at a 95% confidence interval. The regression line is a good fit to the data with a R2

value equal to 0.8344.

Figure 4-28 was created from the data in Table 6 and Table 15. Data in Figure 4-

28 show the percent external top shell gamma dose absorbed internally in the clam shells

as compared to the mean thickness of the top shell of the clams. For mean thickness of

the top shell the range is 0.26 cm to 0.33 cm, the median is 0.29 cm and mean is 0.29 cm.

The percent external top shell dose absorbed internally range is 61% to 112%, the median

is 95% and the mean is 93%.

The shell thickness does not appear to affect the dose received in Figure 4-28. Data

in Figure 4-28 are more uniform than the data for electron beam (Figure 4-18) and the

data for x-ray (Figure 4-23). Linear regression of the data shows a negative relationship

between percentage of external dose absorbed internally and the mean top shell thickness

at a 95% confidence interval. However, the fit of the line is not good with a R2 value of

0.0485. Multiple linear regression of this data shows no statistically significant

relationship (P>0.05) between percentage of external dose absorbed internally and the

mean top shell thickness. Thickness does not have a statistically significant effect on

percentage of external dose absorbed internally for electron beam, x-ray or gamma.










1.5
1.4
o 1.3
S1.2
1.1
0 1 I
0.9
E 0.8
0 0.7
LU 0.6 -
S0.5
E 0.4
o 0.3
-0 0.2
0.1
0 -
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Mean Top Shell Thickness (cm)

Figure 4-28. Percent external top shell dose absorbed internally in the clam shells as
compared to the mean thickness of the top shell of the clams irradiated at
doses of 1 kGy and 3 kGy with gamma at Food Technology Inc. (7/6/05).
Solid line shows linear regression of data with a=0.05 (y = -0.9988x + 1.2254
R2 = 0.0485).

Figure 4-29 was created from the data in Table 5 and Table 15. Data in Figure 4-

29 show the percent external top shell gamma dose absorbed internally in the clam shells

as compared to the curvature of the top shell of the clams. For curvature of the top shell

the range is 0.26 to 0.39, the median is 0.33 and mean is 0.33. The percent external top

shell dose absorbed internally for gamma irradiation range is 61% to 112%, the median is

95% and the mean is 93%. The data for the gamma (Figure 4-29) is more uniform than

the data for electron beam (Figure 4-19) and x-ray (Figure 4-24). A very small negative

relationship is exhibited with linear regression of the data at a 95% confidence interval.

With a R2 value of 0.0003 the regression line does not fit the data very well however. In

addition, multiple linear regression models of the data show no statistically significant

relationship (P>0.05) between the percentage of external dose absorbed internally and the










top shell curvature. Curvature is also not a factor in determining the percentage of

external dose absorbed internally for electron beam, x-ray or gamma.

1.5
1.4
1.3
S1.2
1.1
o 1
S0.9
E 0.8
qL--
0 0.7
x
w 0.6 -
0.5
E 0.4
0.3
0.2
0.1
0 -
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Top Shell Curvature


Figure 4-29. Percent external top shell dose absorbed internally in the clam shells as
compared to the curvature of the top shell of the clams irradiated at doses of
IkGy and 3 kGy with gamma at Food Technology Inc. (7/6/05). Solid line
shows linear regression of data with a=0.05 (y = -0.0652x + 0.9547 R2
0.0003).

Figure 4-30 was created from the data in Table 4 and Table 15. Data in Figure 4-

30 show the percent external top shell dose absorbed internally in the clam shells as

compared to the weight of the top shell of the clams. For weight of the top shell the

range is 10.0g to 20.6g, the median is 13.0g and mean is 13.9g.

The percent external top shell dose absorbed internally range is 70% to 117%, the

median is 98% and the mean is 96%.

Linear regression shows a negative relationship between percentages of external

dose absorbed internally and top shell weight at a 95% confidence interval. The line does

not have a good fit however the R2 value is only 0.0485. No statistically significant

relationship (P<0.05) exists between external dose absorbed internally and top shell










weight in multiple linear regression models. Weight does not have a statistically

significant relationship to percentage of external dose absorbed internally for any of the

three irradiation sources

1.5
1.4
S1.3
1.2
1.1

0.9 ;'" "
E 0.48 -
S0.7
Cl 0.6



0.2
0.1
0.2
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
Top Shell Weight (g)

Figure 4-30. Percent external top shell dose absorbed internally in the clam shells as
compared to the weight of the top shell of the clam irradiated at doses of IkGy
and 3 kGy with gamma Food Technology Inc. (7/6/05). Solid line shows
linear regression of data with a=0.05 (y = -0.9988x + 1.2254 R2 = 0.0485).

Clams irradiated with electron beam, x-ray or gamma have statistically

significantly different (P<0.05) external doses and internal doses. Percentage of external

dose absorbed internally is not affected by top shell thickness, curvature or weight in

clams irradiated with electron beam, x-ray of gamma. Data for gamma is more tightly

grouped than the data for electron beam or x-ray. Gamma also does not exhibit the

concentration effect that electron beam and x-ray exhibit. For these reasons gamma is the

most promising for irradiating clams industrially.

Future experiments on irradiation of clams are needed to assess the effectiveness of

irradiating clams on a large industrial scale. Experiments examining clams with a larger










range of thicknesses, curvatures and weights could also be performed in order to further

validate the results of this research. These experiments would increase the knowledge of

irradiation of shellfish.

Mussel Irradiation with Electron Beam

Electron beam was also used to irradiate mussels. Mussels were purchased on May

12, 2005, irradiated with electron beam at NCEBFR on June 8, 2005. The mussels were

shucked, measured and loaded with dosimeter strips before irradiation. After irradiation

the dosimeter strips placed on the top mussel shell, bottom mussel shell and in between

the mussel shells were read using spectrophotometery.

6
5.5
5
4 4.5
S4
o 3.5
c 3
S2.5 -
2
1.5 ---
1
1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
External Dose (kGy)

Figure 4-31. The internal absorbed dose shucked mussel shells as compared to the
external absorbed dose of the top shell of shucked mussels after exposure to
electron beam at 1 kGy at NCEBFR (6/8/05). Solid line shows linear
regression of data with a=0.05 (y = -0.0271x + 1.6089 R2 = 0.0007).

Figure 4-31 was created from the data in Table 16. Data in Figure 4-31 show the

internal absorbed dose compared to the external top absorbed dose of the mussel shells

irradiated at a dose of 1 kGy, as determined by the staff of NCEBFR. The doses









absorbed inside the mussel shells range from 1.2 kGy to 2.1 kGy, have a median of 1.5

kGy and have a mean of 1.57 kGy. External top absorbed doses range from 1.3 kGy to

2.3 kGy, have a median of 1.6 kGy and have a mean of 1.63 kGy.

The data for mussels irradiated with electron beam is more tightly grouped than the

data for clams and oysters irradiated with electron beam. The internal doses and external

doses for mussels irradiated at 1 kGy with electron beam are not statistically significantly

different (P>0.05). Even though the means for external dose and internal dose are not

significantly different the data is far from ideal and not as tightly grouped as we would

like. In eleven of the forty seven mussels irradiated at 1 kGy the internal absorbed dose

is higher than the external top absorbed dose. The concentration phenomenon is also

exhibited in mussels as well as clams and mussels. External top dose mean is only 0.06

kGy larger than the internal absorbed dose mean. Linear regression of the data shows a

small negative relationship between the external and internal doses at a 95% confidence

interval. However, the regression line is not a good fit for the data with a R2 value equal

to 0.0007.

Figure 4-32 was created from the data in Table 16. Data in Figure 4-32 show the

internal absorbed dose compared to the external top absorbed dose of the mussel shells

irradiated at a dose of 3 kGy, as determined by the staff of NCEBFR. The internal doses

absorbed by the strips range from 1.3 kGy to 4.1 kGy, have a median of 3.1 kGy and

have a mean of 3.00 kGy. External top absorbed doses range from 1.7 kGy to 4.2 kGy,

have a median of 3.2 kGy and have a mean of 3.20 kGy.






60


6
5.5
5
C 4.5
o 4
0 3.5





1.5,
1
1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
External Dose (Kgy)

Figure 4-32. The internal absorbed dose shucked mussel shells as compared to the
external absorbed dose of the top shell of shucked mussels after exposure at 3
kGy at NCEBFR (6/8/05). Solid line shows linear regression of data with
a=0.05 (y = 0.5566x + 1.2022 R2 = 0.1406).

The external dose and internal dose are statistically significantly different (P<0.05).

The mean dose absorbed internally is 3.00 which is the target dose. Even with this ideal

mean there are thirteen of the fifty three mussels irradiated at 3 kGy with the internal

absorbed dose is higher than the external top absorbed dose. External top dose mean is

0.20 kGy larger than the internal absorbed dose mean. Linear regression of the data

shows a positive relationship between the external doses and internal doses at a

confidence interval of 95%. The regression line is not a very good fit to the data with a

R2 value of 0.1406. Even though the mean is exactly the dose we wanted the data is not

grouped as tightly as we would like to see. The concentration phenomenon also affects

24% of the mussels irradiated with 3 kGy.







61


1.5
1.4
o 1.3 --
1.2
1.1 *
0.9
E 0.8 -
S 0.7 *
L 0.6
0.5
E 0.4
0.3
S0.2
0.1
0
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75
Mean Top Shell Thickness (cm)

Figure 4-33. Percent external top shell dose absorbed internally in the mussel shells as
compared to the mean thickness of the top shell of the mussels irradiated with
electron beam at doses of IkGy and 3 kGy NCEBFR (6/8/05). Solid line
shows linear regression of data with a=0.05 (y = -0.2862x + 1.0008 R2
0.0179).

Figure 4-33 was created from the data in Table 9 and Table 16. Data in Figure 4-

33 show the percent external top shell dose absorbed internally in the mussel shells as

compared to the mean thickness of the top shell of the mussels. For mean thickness of

the top shell the range is 0.1cm to 0.62 cm, the median is 0.13 cm and mean is 0.15 cm.

The percent external top shell dose absorbed internally range is 41% to 150%, the median

is 94% and the mean is 96%.

The thicknesses of the top shells of the mussels are very similar. The percentage of

external dose absorbed internally covers a large rang and is not very uniform. Linear

regression of the data shows a negative relationship between the percentage of external

dose absorbed internally and mean top shell thickness at a 95% confidence interval.

However, the linear regression line is not a good fit with a R2 value of 0.0179. A

statistically significant relationship (P>0.05) is not shown between percentage of external







62


dose absorbed internally and mean top shell thickness in multiple linear regression

models. Percent of external dose absorbed internally is not statistically significantly

affected by top shell thickness for mussels irradiated with electron beam. It was expected

that thickness would have a strong negative relationship to percentage of external dose

absorbed internally, as with oysters and clams.

1.5 *
1.4 *
1.3 -
1.2 -
0 1.1
U,
0 1
0.9
cc
0.8
0.7 *
l 0.6
S0.5
E 0.4-
0.3
0.2
0.1
0 ------------------------------------
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Top Shell Curvature

Figure 4-34. Percent external top shell dose absorbed internally in the mussel shells as
compared to the curvature of the top shell of the mussels irradiated at doses of
IkGy and 3 kGy NCEBFR (6/8/05). Solid line shows linear regression of data
with a=0.05 (y = -0.6613x + 1.0962 R2 = 0.0248).

Figure 4-34 was created from the data in Table 8 and Table 16. Data in Figure 4-

34 show the percent external top shell dose absorbed internally in the mussel shells as

compared to the curvature of the top shell of the mussels. For curvature of the top shell

the range is 0.14 to 0.34, the median is 0.20 and mean is 0.21. The percent external top

shell dose absorbed internally range is 41% to 150%, the median is 94% and the mean is

96%.









The curvatures of the mussels (Figure 4-34) are more uniform than the curvatures

of the oysters (Figure 4-4), but are less uniform than the curvatures of the clams (Figure

4-19). A negative relationship is shown between percentage of external dose absorbed

internally and top shell curvature in linear regression models performed at a 95%

confidence interval. The fit of the line is not good with a R2 value of 0.0248 however.

Multiple linear regression models do not show a statistically significant relationship

(P>0.05) between percentage of external dose absorbed internally and top shell curvature.

Figure 4-35 was created from the data in Table 7 and Table 16. Data in Figure 4-

35 show the percent external top shell dose absorbed internally in the clam shells as

compared to the weight of the top shell of the clams. For weight of the top shell the

range is 2.0g to 6.8g, the median is 3.1g and mean is 3.2g.

The percent external top shell dose absorbed internally range is 41% to 150%, the

median is 94% and the mean is 95%.

Linear regression shows a small negative relationship between percentages of

external dose absorbed internally and top shell weight at a 95% confidence interval. The

line does not have a good fit however the R2 value is only 0.0013. No statistically

significant relationship (P>0.05) exists between external dose absorbed internally and top

shell weight in multiple linear regression models.

The data for mussels irradiated with electron beam are very similar to the data for

oysters and clams irradiated with electron beam. All of the external doses and internal

doses of shellfish irradiated with electron beam are statistically significantly different

(P<0.05) except the mussels irradiated with electron beam at 1 kGy. Even with similar

means the data is not as tightly grouped as the data for gamma or x-ray. Electron beam










also exhibits the concentration phenomenon in all three species of shellfish investigated.

Top shell thickness, curvature and weight do not statistically significantly affect the

percentage of external dose absorbed internally in oysters, clams or mussels irradiated

with electron beam. Electron beam does not provide the uniformity of dose that we

would like for any of the three shellfish investigated.

2

1.8

1.6

1.4
0
o 1.2 -
0.
0

E 0.8 -
S0.6

0.4 -
0.2
0 ----------------------------------
0 1 2 3 4 5 6 7 8
Top Shell Wt (g)

Figure 4-35. Percent external top shell dose absorbed internally in the mussel shells as
compared to the weight of the top shell of the mussel irradiated at doses of
IkGy and 3 kGy with electron beam NCEBFR (6/8/05). Solid line shows
linear regression of data with a=0.05 (y = -0.0074x + 0.9827 R2 = 0.0013).

There are numerous future experiments that may help us better understand how to

effectively use electron beam irradiation with shellfish. Irradiating shellfish on the half

shell may be a viable option for irradiating with electron beam. The concentration

phenomenon that is seen in electron beam also needs to be further investigated.

Experiments with different dosimetery methods, such as alanine dosimeters, may provide

a better understanding of this phenomenon. Future experiments may help to provide

better understanding and uses for electron beam.









Mussel Irradiation with X-ray

The second set of experiments for this research was performed with x-ray

irradiation of shucked mussels. Mussels were purchased on May 12, 2005, irradiated

with x-ray at NCEBFR on June 26, 2005. The mussels were shucked, measured,

irradiated with electron beam and loaded with dosimeter strips during the period in-

between. After irradiation with x-ray the dosimeter strips placed on the top mussel shell,

bottom mussel shell and in between the mussel shells were read using

spectrophotometery.

6
5.5
5
4 4.5
4 4
o 3.5
3 3
S2.5
2 -
1.5 -tt-t


1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
External Dose (kGy)

Figure 4-36. The internal absorbed dose shucked mussel shells as compared to the
external absorbed dose of the top shell of shucked mussels after exposure to x-
ray at 1 kGy at NCEBFR (6/26/05). Solid line shows linear regression of data
with a=0.05 (y = 0.0799x + 1.6661 R2 = 0.004).

Figure 4-36 was created from the data in Table 17. Data in Figure 4-36 show the

internal absorbed dose compared to the external top absorbed dose of the mussel shells

irradiated by x-ray at a dose of 1 kGy, as determined by the staff of NCEBFR. The

internal doses absorbed by the strips range from 1.5 kGy to 2.2 kGy, have a median of









1.8 kGy and have a mean of 1.81 kGy. External top absorbed doses range from 1.6 kGy

to 2.1 kGy, have a median of 1.8 kGy and have a mean of 1.81 kGy.

The mean dose absorbed was larger than the IkGy dose given as determined by

NCEBFR for both external and internal dosimeters. Both doses at 1 kGy and 3 kGy are

the same. The data in Figure 4-36 are much more uniform than the data for electron

beam. The external doses and internal doses of mussels irradiated at 1 kGy with x-ray

are not statistically significantly different (P>0.05). As with mussels irradiated with

electron beam at 1 kGy the mean may be similar, but the data is not as tightly grouped as

with gamma. Fifteen of the forty seven mussels irradiated with x-ray at 1 kGy have an

internal absorbed dose that is higher than the external top absorbed dose. Linear

regression of the data at a 95% confidence interval shows a small positive relationship

between external dose and internal dose. With a R2 value of 0.004 the regression line is

not a good fit for the data however.

Figure 4-37 was created from the data in Table 17. Data in Figure 4-37 show the

internal absorbed dose compared to the external top absorbed dose of the mussel shells

irradiated by x-ray at a dose of 3 kGy, as determined by the staff of NCEBFR. The

internal doses absorbed by the strips range from 1.8 kGy to 5.0 kGy, have a median of

4.4 kGy and have a mean of 4.29 kGy. External top absorbed doses range from 1.6 kGy

to 5.2 kGy, have a median of 4.4 kGy and have a mean of 4.29 kGy.

The means of the internal doses and the external doses are equal. However, in

nineteen of the fifty three mussels irradiated at 3 kGy the internal absorbed dose is higher

than the external top absorbed dose. The concentration phenomenon is also seen in

mussels irradiated with x-ray. External doses and internal doses are not statistically










significantly different (P>0.05). A positive relationship between external dose and

internal dose is shown by linear regression of the data at a 95% confidence interval. The

regression line is a good fit to the data with a R2 value of 0.8522. The data for mussels

irradiated with x-ray are more tightly grouped than the data for oysters or clams irradiated

with x-ray. Even though mussels irradiated with x-ray have means that are not

statistically significantly different (P>0.05) the data is not as tightly grouped as the data

for mussels irradiated with gamma.


6
5.5

5 -
4 .5 A

4
0 3.5
3
S 2.5
2S

1.5


1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
External Dose (Kgy)

Figure 4-37. The internal absorbed dose of shucked mussel shells as compared to the
external absorbed dose of the top shell of shucked mussels after exposure to x-
ray at 3 kGy at NCEBFR (6/26/05). Solid line shows linear regression of data
with a=0.05 (y = 0.842x + 0.6817 R2 = 0.8522).

Figure 4-38 was created from the data in Table 9 and Table 17. Data in Figure 4-

38 show the percent external top shell x-ray dose absorbed internally in the mussel shells

as compared to the mean thickness of the top shell of the mussels. For mean thickness of

the top shell the range is 0.1 cm to 0.62 cm, the median is 0.13 cm and mean is 0.15 cm.







68


The percent external top shell dose absorbed internally range is 79% to 122%, the median

is 100% and the mean is 100%.


1.5
1.4
1.3
1.2





0.1
1 -
o Afi
a 0.9
0.8 -
S0.7 5 0 0 0 0
X
o 0.6 -
Cr 0.5 -
S0.4 -
0.3 -
0.2 -
0.1 -

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75
Mean Top Shell Thickness (cm)


Figure 4-38. Percent external top shell dose absorbed internally in the mussel shells as
compared to the mean thickness of the top shell of the mussels irradiated at
doses of IkGy and 3 kGy with x-ray NCEBFR (6/26/05). Solid line shows
linear regression of data with a=0.05 (y = 0.2194x + 0.9718 R2 = 0.0408).

The mussel top shell thicknesses examined in this research did not cover a large

range. Linear regression of the data shows a positive relationship between the percentage

of external doses absorbed internally and the mean top shell thickness at a confidence

interval of 95%. Yet, the regression line does not fit the data very well with a R2 value of

0.0408. Multiple linear regressions of the data do not show a statistically significant

relationship (P>0.05) between percentage of external doses absorbed internally and the

mean top shell thickness. Top shell thickness does not have a statistically significant

effect on the percentage of external dose absorbed internally for oysters, clams or mussels

irradiated with x-ray.







69


1.5
1.4
1.3
1.2- iA A
V 1.1 A A


S0.8 -
0.7
lw 0.6
C 0.5
E 0.4
S0.3
0.2
0.1
0 -
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Top Shell Curvature

Figure 4-39. Percent external top shell dose absorbed internally in the mussel shells as
compared to the curvature of the top shell of the mussels irradiated at doses of
IkGy and 3 kGy with x-ray at NCEBFR (6/26/05). Solid line shows linear
regression of data with a=0.05 (y = 0.0654x + 0.9904 R2 = 0.0009).

Figure 4-39 was created from the data in Table 8 and Table 17. Data in Figure 4-

39 show the percent external top shell x-ray dose absorbed internally in the mussel shells

compared to the curvature of the top shell of the mussels. For curvature of the top shell

the range is 0.14 to 0.39, the median is 0.20 and mean is 0.21. The percent external top

shell dose absorbed internally range is 79% to 122%, the median is 100% and the mean is

100%.

The data for curvature are relatively uniform covering a small range except for one

offset data point. Although, the regression line is not a good fit with a R2 value of 0.0009

a positive relationship between percentage of external dose absorbed internally and top

shell curvature is seen in linear regression models at a 95% confidence interval. Multiple

linear regression of the data shows no statistically significant relationship (P>0.05)

between the percentage of external dose absorbed internally and top shell curvature.










2
1.8
1.6
a 1.4



I 0 .8 -------,------------------
0.6

0.4
0






0.2
0 ------------------------------------
0 1 2 3 4 5 6 7 8 9 10
Top Shell Wt (g)

Figure 4-40. Percent external top shell dose absorbed internally in the mussel shells as
compared to the weight of the top shell of the mussel irradiated at doses of
IkGy and 3 kGy with x-ray NCEBFR (6/26/05). Solid line shows linear
regression of data with a=0.05 (y = 0.0033x + 0.9933 R2 = 0.001).

Figure 4-40 was created from the data in Table 7 and Table 17. Data in Figure 4-

40 show the percent external top shell dose absorbed internally in the clam shells as

compared to the weight of the top shell of the clams. For weight of the top shell the

range is 2.0g to 6.8g, the median is 3.1g and mean is 3.2g. The percent external top shell

dose absorbed internally range is 79% to 122%, the median is 100% and the mean is

100%.

Linear regression shows a small negative relationship between percentages of

external dose absorbed internally and top shell weight at a 95% confidence interval. The

line does not have a good fit however the R2 value is only 0.001. No statistically

significant relationship (P>0.05) exists between external dose absorbed internally and top

shell weight in multiple linear regression models.









Unlike oysters and clams, mussels irradiated with x-ray are not statistically

significantly different (P>0.05). The data for mussels irradiated with x-ray are more

tightly grouped than the data for oysters or clams irradiated with x-ray. Top shell

thickness, curvature and weight are also not statistically significantly affecting the

percentage of external dose absorbed internally for any of the three species of shellfish

irradiated with x-ray. Although x-ray does exhibit the concentration phenomenon in all

of the shellfish investigated, x-ray may be a viable option for irradiating mussels. Future

experiments are needed to further expand the knowledge on irradiation of mussels.

Experiments with different dosimetry methods may provide a better understanding of the

concentration effect seen in the shellfish irradiated with x-ray.

Mussel Irradiation with Gamma

A gamma source was also used to irradiate the oysters. Mussels were purchased on

May 12, 2005, irradiated with gamma at Food Technology Inc. on July 6, 2005. The

mussels were shucked, measured, irradiated with electron beam, irradiated with x-ray and

loaded with dosimeter strips before irradiation with gamma. After irradiation with

gamma the dosimeter strips placed on the top mussel shell, bottom mussel shell and in

between the mussel shells were read using spectrophotometery.

Figure 4-41 was created from the data in Table 18. Data in Figure 4-41 show the

internal absorbed dose compared to the external top absorbed dose of the mussel shells

irradiated by gamma at a dose of 1 kGy, as determined by the staff of Food Technology

Inc. The internal doses range from 1.6 kGy to 2.0 kGy, have a median of 1.7 kGy and

have a mean of 1.73 kGy. External top absorbed doses range from 1.6 kGy to 2.2 kGy,

have a median of 1.9 kGy and have a mean of 1.89 kGy.










6
5.5
5
C4.5
^r 4
o 3.5
c 3
S2.5
2 -
1.5
1
1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
External Dose (kGy)

Figure 4-41. The internal absorbed dose shucked mussel shells as compared to the
external absorbed dose of the top shell of shucked mussels after exposure to
gamma at 1 kGy at Food Technology Inc. (7/6/05). Solid line shows linear
regression of data with a=0.05 (y = 0.4832x + 0.813 R2 = 0.3341).

The mean dose absorbed was larger than the IkGy dose given as determined by

Food Technology Inc. for both external and internal dosimeters. External doses and

internal doses are statistically significantly different (P<0.05) for mussels irradiated at 1

kGy with gammas. None of the forty seven mussels irradiated with gamma at 1 kGy have

an internal absorbed dose higher than the external top absorbed dose. The gammas do

not appear to have the concentration effect with in the shell that the electron beam and x-

rays have. External top dose mean is 0.16 kGy larger than the internal absorbed dose

mean. Linear regression of the data shows a positive relationship between external dose

and internal dose with a R2 value of 0.3341 at a confidence interval of 95%.

Figure 4-42 was created from the data in Table 18. Data in Figure 4-42 show the

internal absorbed dose compared to the external top absorbed dose of the mussel shells

irradiated by gamma at a dose of 3 kGy, as determined by the staff of Food Technology










Inc. The internal doses absorbed range from 1.6 kGy to 5.0 kGy, have a median of 4.4

kGy and have a mean of 4.23 kGy. External top absorbed doses range from 1.8 kGy to

5.0 kGy, have a median of 4.5 kGy and have a mean of 4.36 kGy.

6 -
5.5
5
C 4.5
4 4
S3.5
S3
2.5
2 -
1.5 -
1
1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
External Dose (Kgy)

Figure 4-42. The internal absorbed dose of shucked mussel shells as compared to the
external absorbed dose of the top shell of shucked mussels after exposure to
gamma at 3 kGy at Food Technology Inc. (7/6/05). Solid line shows linear
regression of data with a=0.05 (y = 0.9897x 0.0884 R2 = 0.9634).

The data for mussels irradiated with gamma are tightly fit along a straight line and

clearly show the linear relation between internal dose and external dose. Zero of the

mussels irradiated with gamma at 3 kGy have an internal absorbed dose that is higher

than the external top absorbed dose. External top dose mean is 0.13 kGy larger than the

internal absorbed dose mean. Mussels irradiated at 3 kGy with gammas have

statistically significantly different (P<0.05) external doses and internal doses. Linear

regression of the data shows a positive relationship between the external and internal

doses at a 95% confidence interval. The regression line is almost a perfect fit for this










data with a R2 value of 0.9634. Gamma shows the tightly grouped relationship that we

want when irradiating shellfish.

1.5
1.4
^ 1.3
1.2
1.1
5 1 -- I I-----------------
10 ... .
0.9 M-.i-i-
E 0.8
0.7
L 0.6




0.1
0
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75
Mean Top Shell Thickness (cm)

Figure 4-43. Percent external top shell dose absorbed internally in the mussel shells as
compared to the mean thickness of the top shell of the mussels irradiated at
doses of 1 kGy and 3 kGy with gamma at Food Technology Inc. (7/6/05).
Solid line shows linear regression of data with a=0.05 (y = -0.0671x + 0.953
R2 = 0.0108).

Figure 4-43 was created from the data in Table 9 and Table 18. Data in Figure 4-

43 show the percent external top shell gamma dose absorbed internally in the mussel

shells as compared to the mean thickness of the top shell of the mussels. For mean

thickness of the top shell the range is 0.1 cm to 0.62 cm, the median is 0.13 cm and mean

is 0.15 cm. The percent external top shell dose absorbed internally range is 80% to

100%, the median is 95% and the mean is 94%.

The shell thickness does not appear to affect the dose received in Figure 4-43. Data

in Figure 4-43 are more uniform than the data for electron beam (Figure 4-33) and the

data for x-ray (Figure 4-38). Linear regression of the data shows a small negative

relationship between percentage of external dose absorbed internally and the mean top










shell thickness at a 95% confidence interval. However, the regression line is not a good

fit for the data with a R2 value of 0.0108. Multiple linear regression models do not shows

a statistically significant relationship (P>0.05) between percentage of external dose

absorbed internally and the mean top shell thickness. None of the three species of

shellfish examined in this research show a statistically significant relationship (P>0.05)

between top shell thickness and the percentage of external dose absorbed internally.

1.5
1.4
1.3
1.2
S1.1
o 1-.
0.9 h
E 0.8
0.7
LW 0.6
S0.5
E 0.4
-* 0.3
0.2
0.1
0
0 ------------------------------------
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Top Shell Curvature

Figure 4-44. Percent external top shell dose absorbed internally in the mussel shells as
compared to the curvature of the top shell of the mussels irradiated at doses of
IkGy and 3 kGy with gamma at Food Technology Inc. (7/6/05). Solid line
shows linear regression of data with a=0.05 (y = 0.1562x + 0.9108 R2
0.0152).

Figure 4-44 was created from the data in Table 8 and Table 18. Data in Figure 4-

44 shows the percent external top shell gamma dose absorbed internally in the mussel

shells as compared to the curvature of the top shell of the mussels. For curvature of the

top shell the range is 0.11 to 0.88, the median is 0.23 and mean is 0.24. The percent

external top shell dose absorbed internally for gamma irradiation range is 74% to 100%,

the median is 95% and the mean is 93%.









The data for the gamma (Figure 4-44) is more uniform than the data for electron

beam (Figure 4-34) and x-ray (Figure 4-39). Linear regression of the data shows a

positive relationship between the percentage of external dose absorbed internally and the

top shell curvature at a 95% confidence level. No statistically significant relationship

(P>0.05) is shown between the percentage of external dose absorbed internally and the

top shell curvature in multiple linear regression models. Curvature does not affect the

percentage of external dose absorbed internally for oysters, clams or mussels.

Figure 4-45 was created from the data in Table 7 and Table 18. Data in Figure 4-

45 show the percent external top shell dose absorbed internally in the clam shells as

compared to the weight of the top shell of the clams. For weight of the top shell the

range is 2.0g to 6.8g, the median is 3.1g and mean is 3.2g. The percent external top shell

dose absorbed internally range is 74% to 100%, the median is 94% and the mean is 93%.

Linear regression shows a small negative relationship between percentages of external

dose absorbed internally and top shell weight at a 95% confidence interval. The line does

not have a good fit however the R2 value is only 0.0118. No statistically significant

relationship (P>0.05) exists between external dose absorbed internally and top shell

weight in multiple linear regression models. Top shell weight does not have a significant

affect on the percentage of external dose absorbed internally for any of the three shellfish

examined.

The external doses and internal doses are statistically significantly different for the

oysters, clams and mussels irradiated with gamma. However, gamma also provided the

most tightly grouped data of all of the three irradiation sources tested. This is as to be

expected due to the higher energy and therefore the higher penetration of gamma










irradiation. Top shell thickness, curvature and weight do not have a statistically

significant relationship (P>0.05) to percentage of external dose absorbed internally for

any of the species of shellfish investigated in this research. Gamma is the most

promising of the three types of irradiation studied for irradiating oysters, clams, and

mussels.

2
1.8
1.6
1.4
o
a 1.2

I- 1 ne* *
S0.8
0.6


0
0.2


0 1 2 3 4 5 6 7 8 9 10
Top Shell Wt (g)

Figure 4-45. Percent external top shell dose absorbed internally in the mussel shells as
compared to the weight of the top shell of the mussel irradiated at doses of
IkGy and 3 kGy with gamma Food Technology Inc. (7/6/05). Solid line
shows linear regression of data with a=0.05 (y = 0.0068x + 0.9214 R2
0.0118).

Oysters have the least tightly grouped data of the three shellfish studied for electron

beam, x-ray and gamma. Data for clams are not as tightly grouped as data for mussels

irradiated with electron beam, x-ray and gamma. This data confirms what we expected.

Mussel should have the most uniform irradiation results since they have the thinnest and

most uniform shells of the shellfish investigated. Irradiation data for clams are less

uniform than mussels due to their thicker and less uniform shells and oysters have the

least uniform irradiation data since their shells are the thickest and least uniform.









However, when the shell geometry and weight are investigated for the three shellfish it is

determined that shell thickness, curvature and weight do not statistically significantly

affect the percentage of external dose absorbed internally in oysters, clams and mussels

irradiated with electron beam, x-ray and gamma. It was expected that thickness,

curvature and weight would all have an effect on percentage of external dose absorbed

internally in oysters, clams and mussels. One reason for this may be another more

important factor overshadowing the effects thickness, curvature and weight. Another

reason for this unexpected result may be the technique used to measure the shells. The

shells were all measured on a macroscopic scale, yet the diverse landscape of the shell

may yield better results if the shell is examined microscopically. These are all possible

explanations for the unexpected results in these experiments.

Gamma is the most promising of the three sources of irradiation studied. The most

tightly grouped data is provided by gamma for oysters, clams and mussels. X-ray

provides tighter grouped data than electron beam does. This is as expected. The energy

and penetration of gammas are the highest, x-rays have the next highest energy and

penetration and electron beam have the lowest energy and penetration. X-ray and

electron beam exhibit the concentration phenomenon where the internal dose is higher

than the applied external dose. It is for these reasons and others that gamma irradiation is

the most viable source for irradiating shellfish on a large industrial scale.

This research creates questions that should be answered by future research. First,

different dosimeters could be used to help clarify the data presented in this research. The

use of different dosimetry may also help to clarify the concentration phenomenon that is

seen with electron beam and x-ray. Also future experiments should be performed with









microscopic measuring techniques to examine thickness and curvature. As mentioned

above experiments with shellfish on the half shell may be promising for electron beam

and x-ray since the shell is not present as a barrier. Large scale experiments, using tons

of shellfish, with gamma irradiation should also be performed to determine the

penetration of dose in pallets of shellfish. Economic experiments to compare electron

beam, x-ray and gamma may also provide valuable information about the practicality of

large scale irradiation of shellfish. With the help of experiments such as these irradiation

of shellfish may become viable industrial practice.














CHAPTER 5
SUMMARY AND CONCLUSIONS

The primary objective of this research was to compare and contrast the percentage

of absorption of irradiation in oyster, clam and mussel shells using gamma, electron beam

and x-ray irradiation sources at dosages of 1 kGy and 3 kGy. Oyster, clam and mussel

shells were assessed for differences in external absorbed dose and internal absorbed dose

for electron beam, x-ray and gamma sources. Furthermore, the thickness, weight and

curvatures for oyster, clam and mussel shells were assessed with respect to the effect on

percentage of applied dose absorbed internally.

When clam and oyster shells were irradiated using gamma, x-ray or electron beam

at 1 kGy and 3 kGy, the absorbed internal dose was less than the external dose and was

determined to be significantly different (P<0.05) when compared to the external absorbed

shell dose. When mussel shells were irradiated using electron beam at 1 kGy or x-ray at

1 kGy and 3 kGy no statistical significant differences (P>0.05) were determined to exist

between the external and internal absorbed dose. However, when mussel shells were

irradiated with electron beam at 3 kGy and gamma irradiation at 1 kGy and 3 kGy,

significant differences (P<0.05) were determined to exist between the external and

internal absorbed doses. When oyster, clam and mussel shells were irradiated with

electron beam and x-ray a concentration phenomenon, where internal doses were greater

than the external doses, was exhibited. Specifically, the concentration phenomenon was

exhibited in 12% of the oyster shells, 12% of the clam shells and 24% of the mussel

shells irradiated with electron beam. The concentration phenomenon was exhibited in









14% of the oyster shells, 17% of the clam shells and 34% of the mussel shells irradiated

with x-ray.

When top shell thickness, weight and curvature for oyster, clam and mussel shells

were statistically compared to the percentage ratio of external/internal absorbed dose, no

significant relationship (P>0.05) was revealed. Specifically, no statistical relationship

was demonstrated between the percentage external dose absorbed internally and the top

shell thickness, curvature of the shell and weight of the shell using electron beam, x-ray

and gamma at 1 kGy and 3 kGy. Therefore, oyster, clam and mussel shell thickness,

shell curvature and shell weight did not have a statistical significant relationship or

influence on the percentage of external/internal absorbed dose at 1 kGy and 3 kGy.

Reasons for the differences between external and internal absorbed doses and

concentration phenomenon are unclear and can not be accounted for by differences in

shell thickness, shell weight or shell curvature.

















APPENDIX A
OYSTER, CLAM, AND MUSSEL MEASUREMENTS

Oyster Measurements


Table A-1. Oyster Weight Measurements in g (5/1/05)
Oyster Overall Meat Shell Top Bottom Shell/ Top/ Top/ Bottom/
wt wt wt Shell wt Shell wt Meat Bottom Meat Meat
1 84.2 16.1 68.1 47.3 20.8 4.23 2.27 2.94 1.29
2 67.8 6.1 61.7 30.4 31.3 10.11 0.97 4.98 5.13
3 59.1 5.9 53.2 32.1 21.1 9.02 1.52 5.44 3.58
4 55.5 6.8 48.7 29.5 19.2 7.16 1.54 4.34 2.82
5 37.0 4.2 32.8 19.4 13.4 7.81 1.45 4.62 3.19
6 64.1 8.0 56.1 33.3 22.8 7.01 1.46 4.16 2.85
7 41.2 3.6 37.6 20.8 16.8 10.44 1.24 5.78 4.67
8 57.7 4.5 53.2 39.8 13.4 11.82 2.97 8.84 2.98
9 91.8 12.4 79.4 48.3 31.1 6.40 1.55 3.90 2.51
10 72.5 11.8 60.7 37.5 23.2 5.14 1.62 3.18 1.97
11 50.9 8.0 42.9 26.4 16.5 5.36 1.60 3.30 2.06
12 47.1 5.6 41.5 23 18.5 7.41 1.24 4.11 3.30
13 56.3 7.6 48.7 32.6 16.1 6.41 2.02 4.29 2.12
14 45.0 6.0 39.0 23.4 15.6 6.50 1.50 3.90 2.60
15 63.7 9.2 54.5 32.2 22.3 5.92 1.44 3.50 2.42
16 107.8 15.9 91.9 53.7 38.2 5.78 1.41 3.38 2.40
17 105.1 12.6 92.5 49.6 42.9 7.34 1.16 3.94 3.40
18 59.6 7.3 52.3 30.4 21.9 7.16 1.39 4.16 3.00
19 66.7 9.5 57.2 35.8 21.4 6.02 1.67 3.77 2.25
20 64.7 10.0 54.7 33.7 21.0 5.47 1.60 3.37 2.10
21 138.9 17.3 121.6 76.2 45.4 7.03 1.68 4.40 2.62
22 48.9 7.9 41.0 22.9 18.1 5.19 1.27 2.90 2.29
23 57.8 7.9 49.9 31.9 18.0 6.32 1.77 4.04 2.28
24 70.8 9.0 61.8 36.1 25.7 6.87 1.40 4.01 2.86
25 81.9 11.6 70.3 42.2 28.1 6.06 1.50 3.64 2.42
26 41.5 6.2 35.3 18.7 16.6 5.69 1.13 3.02 2.68
27 47.0 7.1 39.9 24.3 15.6 5.62 1.56 3.42 2.20
28 63.0 12.0 51.0 32.7 18.3 4.25 1.79 2.73 1.53
29 83.2 13.9 69.3 47.4 21.9 4.99 2.16 3.41 1.58
30 57.0 9.3 47.7 33.2 14.5 5.13 2.29 3.57 1.56
31 43.6 5.1 38.5 22.2 16.3 7.55 1.36 4.35 3.20
32 81.6 8.7 72.9 45.7 27.2 8.38 1.68 5.25 3.13
33 57.0 6.3 50.7 29.7 21.0 8.05 1.41 4.71 3.33
34 57.7 8.0 49.7 30.9 18.8 6.21 1.64 3.86 2.35
35 58.5 8.4 50.1 32.8 17.3 5.96 1.90 3.90 2.06
36 86.9 11.1 75.8 44.5 31.3 6.83 1.42 4.01 2.82
37 44.5 4.0 40.5 28 12.5 10.13 2.24 7.00 3.13
38 56.1 8.3 47.8 33.5 14.3 5.76 2.34 4.04 1.72
39 59.4 10.2 49.2 29.9 19.3 4.82 1.55 2.93 1.89
40 45.5 9.1 36.4 24.3 12.1 4.00 2.01 2.67 1.33











Table A-1. Continued
Oyster Overall Meat Shell Top Bottom Shell/ Top/ Top/ Bottom/
wt wt wt Shell wt Shell wt Meat Bottom Meat Meat
41 41.0 6.8 34.2 21.5 12.7 5.03 1.69 3.16 1.87
42 45.4 7.1 38.3 20.1 18.2 5.39 1.10 2.83 2.56
43 54.0 8.8 45.2 26.8 18.4 5.14 1.46 3.05 2.09
44 62.5 6.6 55.9 35.5 20.4 8.47 1.74 5.38 3.09
45 55.6 10.8 44.8 27.8 17.0 4.15 1.64 2.57 1.57
46 39.1 7.0 32.1 19.3 12.8 4.59 1.51 2.76 1.83
47 65.0 14.9 50.1 32.3 17.8 3.36 1.81 2.17 1.19
48 57.0 15.5 41.5 25.9 15.6 2.68 1.66 1.67 1.01
49 83.8 9.2 74.6 48.0 26.6 8.11 1.80 5.22 2.89
50 53.5 11.0 42.5 29.0 13.5 3.86 2.15 2.64 1.23
51 69.2 8.6 60.6 39.1 21.5 7.05 1.82 4.55 2.50
52 54.3 10.7 43.6 27.8 15.8 4.07 1.76 2.60 1.48
53 37.3 5.7 31.6 20.7 10.9 5.54 1.90 3.63 1.91
54 48.9 6.9 42.0 30.0 12.0 6.09 2.50 4.35 1.74
55 48.8 6.2 42.6 24.7 17.9 6.87 1.38 3.98 2.89
56 34.2 5.9 28.3 17.3 11.0 4.80 1.57 2.93 1.86
57 42.2 6.0 36.2 21.0 15.2 6.03 1.38 3.50 2.53
58 66.6 12.7 53.9 34.6 19.3 4.24 1.79 2.72 1.52
59 54.8 4.6 50.2 28.8 21.4 10.91 1.35 6.26 4.65
60 54.0 8.2 45.8 29.1 16.7 5.59 1.74 3.55 2.04
61 63.5 8.8 54.7 29.4 25.3 6.22 1.16 3.34 2.88
62 67.0 6.2 60.8 36.0 24.8 9.81 1.45 5.81 4.00
63 63.7 13.4 50.3 32.5 17.8 3.75 1.83 2.43 1.33
64 129.2 12.5 116.7 69.3 47.4 9.34 1.46 5.54 3.79
65 50.1 6.6 43.5 27.2 16.3 6.59 1.67 4.12 2.47
66 80.7 10.5 70.2 42.7 27.5 6.69 1.55 4.07 2.62
67 48.8 9.0 39.8 22.1 17.7 4.42 1.25 2.46 1.97
68 73.6 9.6 64.0 48.7 15.3 6.67 3.18 5.07 1.59
69 108.3 14.0 94.3 65.6 28.7 6.74 2.29 4.69 2.05
70 87.3 9.2 78.1 46.0 32.1 8.49 1.43 5.00 3.49
71 65.6 10.6 55.0 35.5 19.5 5.19 1.82 3.35 1.84
72 108.6 12.6 96.0 62.0 34.0 7.62 1.82 4.92 2.70
73 51.7 9.8 41.9 25.5 16.4 4.28 1.55 2.60 1.67
74 42.3 8.6 33.7 19.8 13.9 3.92 1.42 2.30 1.62
75 65.5 10.1 55.4 34.7 20.7 5.49 1.68 3.44 2.05
76 60.1 7.6 52.5 27.4 25.1 6.91 1.09 3.61 3.30
77 54.4 6.9 47.5 28.2 19.3 6.88 1.46 4.09 2.80
78 65.9 10.1 55.8 30.6 25.2 5.52 1.21 3.03 2.50
79 136.8 24.4 112.4 71.9 40.5 4.61 1.78 2.95 1.66
80 81.7 9.8 71.9 39.8 32.1 7.34 1.24 4.06 3.28
81 55.0 8.9 46.1 25.3 20.8 5.18 1.22 2.84 2.34
82 64.1 12.0 52.1 30.6 21.5 4.34 1.42 2.55 1.79
83 59.3 7.5 51.8 32.4 19.4 6.91 1.67 4.32 2.59
84 80.6 13.3 67.3 46.1 21.2 5.06 2.17 3.47 1.59
85 70.5 15.3 55.2 29.2 26.0 3.61 1.12 1.91 1.70
86 55.9 10.9 45.0 29.3 15.7 4.13 1.87 2.69 1.44
87 42.9 9.2 33.7 20.1 13.6 3.66 1.48 2.18 1.48
88 96.4 11.1 85.3 45.0 40.3 7.68 1.12 4.05 3.63
89 62.7 9.8 52.9 32.7 20.2 5.40 1.62 3.34 2.06
90 114.7 13.9 100.8 63.1 37.7 7.25 1.67 4.54 2.71











Table A-1. Continued
Oyster Overall Meat Shell Top Bottom Shell/ Top/ Top/ Bottom/
wt wt wt Shell wt Shell wt Meat Bottom Meat Meat
91 84.3 13.0 71.3 43.9 27.4 5.48 1.60 3.38 2.11
92 52.5 9.6 42.9 22.4 20.5 4.47 1.09 2.33 2.14
93 72.5 8.2 64.3 39.8 24.5 7.84 1.62 4.85 2.99
94 59.3 11.4 47.9 29.5 18.4 4.20 1.60 2.59 1.61
95 38.3 6.9 31.4 18.3 13.1 4.55 1.40 2.65 1.90
96 57.7 10.3 47.4 30.5 16.9 4.60 1.80 2.96 1.64
97 68.7 10.4 58.3 35.2 23.1 5.61 1.52 3.38 2.22
98 55.1 10.7 44.4 28.2 16.2 4.15 1.74 2.64 1.51
99 57.5 9.5 48.0 28.0 20.0 5.05 1.40 2.95 2.11
100 50.4 8.8 41.6 21.8 19.8 4.73 1.10 2.48 2.25


Table A-2. Oyster Dimension Measurements in cm 5/3/05
Oyster Top Top Top Bottom Bottom Bottom Total Total Total
Length Height Width Length Height Width Length Height Width
1 10.6 2.2 5.8 8.3 0.65 4.85 10.6 2.85 5.8
2 6.5 1.65 6.1 5.6 1.05 5.3 6.5 2.7 6.1
3 7.3 1.5 4.5 5.05 0.8 3.65 7.3 2.3 4.5
4 6.3 2.1 6.0 4.8 1.0 5.15 6.3 3.1 6.0
5 6.2 1.3 4.1 5.3 0.9 3.6 6.2 2.2 4.1
6 6.75 1.4 4.8 5.7 1.1 3.9 6.75 2.5 4.8
7 5.8 1.55 4.5 5.15 1.0 3.8 5.8 2.55 4.5
8 6.3 1.5 4.0 5.5 1.05 3.7 6.3 2.55 4.0
9 6.5 0.7 4.7 5.5 1.2 3.9 6.5 1.9 4.7
10 9.4 2.0 4.7 7.5 0.65 4.45 9.4 2.65 4.7
11 7.6 1.6 5.2 6.3 0.45 4.45 7.6 2.05 5.2
12 6.6 1.85 4.75 6.05 1.05 4.15 6.6 2.9 4.75
13 8.2 2.0 4.9 6.7 0.7 4.1 8.2 2.7 4.9
14 7.8 1.6 3.7 6.7 0.65 3.5 7.8 2.25 3.7
15 7.7 1.65 3.95 7.15 0.8 4.1 7.7 2.45 3.95
16 8.4 1.75 7.45 7.1 1.45 5.4 8.4 3.2 7.45
17 8.65 1.85 5.2 7.35 1.5 4.65 8.65 3.35 5.2
18 6.3 1.8 5.6 5.8 0.95 5.1 6.3 2.75 5.6
19 8.4 2.3 4.9 7.35 1.0 4.15 8.4 3.3 4.9
20 7.69 2.0 5.2 6.9 0.8 4.6 7.69 2.8 5.2
21 9.0 2.0 5.2 6.9 0.8 4.6 9.0 2.8 5.2
22 4.45 1.9 3.9 5.3 0.6 3.7 5.3 2.5 3.9
23 7.5 2.3 5.3 5.7 0.9 4.45 7.5 3.2 5.3
24 7.0 1.2 4.75 6.1 1.2 4.05 7.0 2.4 4.75
25 8.4 2.3 4.9 7.35 1.0 4.15 8.4 3.3 4.9
26 6.0 1.4 4.4 5.15 0.9 4.2 6.0 2.3 4.4
27 6.75 1.5 4.9 5.95 0.65 3.85 6.75 2.15 4.9
28 8.8 2.2 5.75 6.8 0.65 4.55 8.8 2.85 5.75
29 9.4 2.1 4.1 8.9 1.0 3.4 9.4 3.1 4.1
30 9.2 1.35 3.9 6.85 0.95 3.4 9.2 2.3 3.9
31 9.05 1.45 4.3 7.2 0.6 3.45 9.05 2.05 4.3
32 6.1 1.6 6.15 6.05 1.0 4.75 6.1 2.6 6.15
33 5.8 1.9 4.1 6.0 0.65 4.3 6.0 2.55 4.3
34 7.65 2.1 4.4 6.7 0.6 4.05 7.65 2.7 4.4
35 7.65 2.1 4.4 6.7 0.6 4.05 4.68 2.7 4.4
36 7.8 1.7 5.6 6.5 1.2 4.5 7.8 2.9 5.6











Table A-2. Continued
Oyster Top Top Top Bottom Bottom Bottom Total Total Total
Length Height Width Length Height Width Length Height Width
37 8.3 2.5 4.75 6.2 0.9 3.8 8.3 3.4 4.75
38 7.7 1.9 3.7 6.4 0.6 3.1 7.7 2.5 3.7
39 9.3 1.45 4.8 8.3 0.6 4.15 9.3 2.05 4.8
40 8.8 1.7 4.2 7.15 0.6 3.55 8.8 2.3 4.2
41 7.5 1.7 3.7 6.85 0.3 3.15 7.5 2.0 3.7
42 6.8 1.5 5.1 5.15 1.0 4.1 6.8 2.5 5.1
43 6.95 1.7 5.1 5.75 1.0 4.0 6.95 2.7 5.1
44 8.3 1.75 2.9 6.3 0.7 2.8 8.3 2.45 2.9
45 6.4 2.4 4.5 5.15 0.95 3.55 6.4 3.35 4.5
46 6.9 1.5 4.0 6.2 0.55 3.4 6.9 2.05 4.0
47 8.79 1.9 5.65 7.4 0.5 4.3 8.79 2.4 5.65
48 7.9 1.95 5.5 5.5 0.7 4.1 7.9 2.65 5.5
49 6.15 1.4 5.5 5.95 1.1 4.0 6.15 2.5 5.5
50 8.9 1.6 4.4 7.5 0.5 3.4 8.9 2.1 4.4
51 8.9 2.2 5.6 7.5 .55 4.6 8.9 2.75 5.6
52 8.7 1.9 5.4 6.8 0.45 4.15 8.7 2.35 5.4
53 9.7 1.8 3.8 7.0 0.55 3.0 9.7 2.35 3.8
54 6.65 1.75 3.75 5.3 0.6 3.0 6.65 2.35 3.75
55 5.65 1.6 5.6 4.9 0.75 3.7 5.65 2.35 5.6
56 8.85 1.15 3.65 6.6 0.55 3.3 8.85 1.7 3.65
57 6.3 1.5 4.85 5.2 0.75 3.95 6.3 2.25 4.85
58 8.45 1.7 7.05 6.9 0.75 4.3 8.45 2.45 7.05
59 6.9 1.45 4.5 6.0 1.1 3.9 6.9 2.55 4.5
60 8.75 2.0 4.75 7.1 1.15 2.7 8.75 3.15 4.75
61 8.8 1.35 4.5 7.5 0.75 3.55 8.8 2.1 4.5
62 6.2 1.6 5.1 5.4 1.75 3.9 6.2 3.35 5.1
63 9.85 2.75 5.1 7.75 0.6 4.2 9.85 3.35 5.1
64 8.5 1.6 6.5 7.2 1.2 6.0 8.5 2.8 6.5
65 6.55 1.7 3.6 5.05 0.8 3.1 6.55 2.5 3.6
66 7.1 2.1 5.75 6.1 1.0 4.9 7.1 3.1 5.75
67 7.1 1.6 4.8 5.8 0.6 3.5 7.1 2.2 4.8
68 7.8 2.55 4.8 6.7 0.5 4.2 7.8 3.05 4.8
69 9.35 2.15 6.0 7.5 .85 4.75 9.35 3.0 6.0
70 9.3 1.45 5.3 6.7 70 4.4 9.3 71.45 5.3
71 9.5 1.8 4.4 6.85 0.6 4.0 9.5 2.4 4.4
72 8.85 1.5 5.75 8.25 0.8 4.9 8.85 2.3 5.75
73 9.15 1.3 3.9 7.65 0.5 3.5 9.15 1.8 3.9
74 6.8 1.7 4.6 7.2 0.55 3.7 7.2 2.25 4.6
75 8.85 1.45 4.6 5.65 0.45 3.7 8.85 1.9 4.6
76 6.3 1.45 4.45 5.85 0.9 4.1 6.3 2.35 4.45
77 6.6 1.6 5.15 5.6 0.9 3.7 6.6 2.5 5.15
78 8.75 1.55 4.9 7.4 0.9 3.6 8.75 2.45 4.9
79 8.6 2.6 5.6 7.7 1.8 4.8 8.6 4.4 5.6
80 7.6 1.9 5.2 6.55 1.45 4.4 7.6 3.35 5.2
81 6.9 1.6 5.0 5.8 1.15 4.1 6.9 2.75 5.0
82 8.65 1.9 5.0 7.0 1.7 4.9 8.65 3.6 5.0
83 7.3 2.4 4.45 5.75 0.7 3.9 7.3 3.1 4.45
84 8.8 1.85 4.55 6.5 0.9 4.2 8.8 2.75 4.55
85 10.5 1.6 5.35 10.2 0.5 4.3 10.5 2.1 5.35
86 7.1 1.6 4.4 5.4 0.85 4.0 7.1 2.45 4.4











Table A-2. Continued
Oyster Top Top Top Bottom Bottom Bottom Total Total Total
Length Height Width Length Height Width Length Height Width
87 7.65 1.75 4.4 5.9 0.65 3.9 7.65 2.4 4.4
88 7.4 2.3 5.0 6.8 1.55 4.05 7.4 3.85 5.0
89 7.65 1.55 4.8 6.55 0.55 4.15 7.65 2.1 4.8
90 9.8 2.1 6.3 7.8 0.85 4.75 9.8 2.95 6.3
91 10.35 2.95 5.0 8.75 0.9 4.05 10.35 3.85 5.0
92 8.6 .95 4.7 6.85 0.55 4.3 8.6 1.5 4.7
93 7.95 7.0 6.0 6.3 0.8 4.95 7.95 7.8 6.0
94 8.1 1.9 4.3 6.9 0.5 3.8 8.1 2.4 4.3
95 7.4 1.5 3.5 5.8 0.5 3.25 7.4 2.0 3.5
96 6.9 2.1 4.4 5.6 0.9 4.1 6.9 3.0 4.4
97 9.0 1.9 5.05 6.9 1.0 4.6 9.0 2.9 5.05
98 8.3 2.1 4.3 6.45 0.6 3.85 8.3 2.7 4.3
99 7.9 2.0 4.35 6.6 0.55 3.8 7.9 2.55 4.35
100 5.7 1.75 4.3 5.35 1.75 4.0 5.7 3.5 4.3

Table A-3. Oyster Thickness Measurements in cm (5/4/05)
Oyster 1Top 2Tp 3Top 4Top 5Top 1Bottom 2Bottom 3Bottom 4Bottom 5Bottom
1 0.231 0.318 0.724 0.533 0.373 0.292 0.277 0.269 0.282 0.470
2 0.445 0.559 0.803 0.658 0.457 0.533 0.302 0.521 0.645 0.287
3 0.221 0.414 0.696 0.635 0.277 0.279 0.566 0.930 0.483 0.343
4 0.787 0.439 0.282 0.292 0.564 0.328 0.254 0.749 0.320 0.523
5 0.538 0.399 0.257 0.368 0.457 0.716 0.211 0.432 0.427 0.193
6 0.625 0.439 0.414 0.340 0.859 0.836 0.381 0.366 0.389 0.686
7 0.343 0.699 0.828 0.305 0.358 0.732 0.427 0.343 0.312 0.320
8 0.356 0.396 0.737 0.445 0.378 0.335 0.505 0.765 0.638 0.696
9 0.792 0.470 0.277 0.533 0.218 0.409 0.668 0.828 0.429 0.892
10 0.513 0.622 0.683 0.457 0.320 0.328 0.353 0.310 0.584 0.546
11 0.180 0.353 0.787 0.536 0.307 0.218 0.417 0.277 0.409 0.292
12 0.645 0.566 0.559 0.406 0.437 0.622 0.790 0.300 0.686 0.335
13 0.536 0.267 0.432 0.551 0.264 0.320 0.414 0.391 0.216 0.434
14 0.201 0.274 0.523 0.325 0.272 0.391 0.267 0.516 0.323 0.450
15 0.262 0.460 0.318 0.295 0.305 0.257 0.282 0.292 0.325 0.259
16 0.635 0.904 0.432 0.620 0.508 0.556 0.810 0.432 0.399 0.528
17 0.389 0.437 0.777 1.064 0.699 0.315 0.561 1.003 0.775 0.704
18 0.765 0.554 0.866 0.526 0.612 0.323 0.544 0.391 0.358 0.447
19 0.312 0.429 0.419 0.584 0.391 0.284 0.401 0.508 0.749 1.092
20 0.386 0.521 0.320 0.401 0.457 0.445 0.508 0.384 0.472 0.584
21 1.019 0.643 0.384 0.493 0.566 0.371 0.643 0.820 0.686 0.318
22 0.328 0.356 0.333 0.282 0.333 0.279 0.333 0.287 0.432 0.414
23 0.765 0.399 0.417 0.559 0.597 0.577 0.414 0.452 0.566 0.338
24 0.551 0.536 0.838 0.622 0.737 0.368 0.445 0.635 1.064 0.356
25 0.142 0.645 1.062 0.749 0.866 0.302 0.409 0.714 0.907 0.483
26 0.361 0.216 0.671 0.267 0.287 0.643 0.445 0.305 0.673 0.312
27 0.381 0.315 0.508 0.528 0.516 0.290 0.305 0.693 0.475 0.503
28 0.305 0.254 0.323 0.521 0.343 0.325 0.394 0.257 0.330 0.526
29 0.411 0.724 1.262 0.513 0.409 0.211 0.483 0.864 0.310 0.409
30 0.218 0.262 0.396 0.536 0.940 0.269 0.401 0.498 0.292 0.500
31 0.127 0.368 0.538 0.211 0.284 0.638 0.493 0.249 0.175 0.287
32 0.599 0.592 0.927 0.681 0.683 0.597 0.531 0.706 0.800 1.105
33 0.300 0.394 0.627 1.240 1.130 0.343 0.361 0.419 0.894 0.785











Table A-3. Continued
Oyster 1Top 2Top 3Top 4Top 5Top 1Bottom 2Bottom 3Bottom 4Bottom 5Bottom
34 0.295 0.556 0.851 0.787 0.673 0.742 0.439 0.419 0.267 0.478
35 0.409 1.143 0.345 0.373 0.251 0.292 0.356 0.541 0.295 0.445
36 0.267 0.544 0.498 1.173 0.902 0.467 0.470 0.719 1.016 0.295
37 0.277 1.067 0.399 0.699 0.678 0.208 0.419 0.648 0.335 0.226
38 0.333 0.340 0.112 0.635 0.358 0.318 0.320 0.437 0.757 0.419
39 0.358 0.523 0.434 0.432 0.229 0.439 0.231 0.414 0.246 0.300
40 0.234 0.295 1.087 0.328 0.297 0.305 0.404 0.297 0.274 0.224
41 0.279 0.406 0.229 1.085 0.236 0.216 0.318 0.340 0.348 0.483
42 0.498 0.401 0.556 0.300 0.295 0.353 0.419 0.279 0.754 0.551
43 0.267 0.325 0.544 0.282 0.500 0.300 0.442 0.833 0.366 0.467
44 0.597 0.389 0.508 0.803 0.917 0.401 0.653 0.429 0.335 0.599
45 0.610 0.244 0.638 1.250 0.607 0.617 0.846 0.785 0.241 0.297
46 0.368 0.259 0.295 0.345 0.320 0.310 0.333 0.203 0.419 0.295
47 0.279 0.391 0.345 0.318 0.488 0.264 0.353 0.312 0.284 0.325
48 0.142 0.378 0.437 0.643 0.518 0.287 0.353 0.432 0.432 0.531
49 0.584 0.381 0.864 0.584 0.749 0.813 0.478 0.323 0.343 0.531
50 0.399 0.231 0.330 0.439 0.414 0.152 0.254 0.262 0.315 0.338
51 0.191 0.338 0.521 1.148 0.422 0.226 0.269 0.452 0.414 0.351
52 0.173 0.264 0.447 0.655 0.470 0.185 0.579 0.394 0.617 0.234
53 0.437 0.500 0.348 0.432 0.282 0.234 0.325 0.546 0.523 0.226
54 0.541 0.381 0.439 0.226 0.429 0.394 0.295 0.394 0.622 0.404
55 0.218 0.561 0.960 0.818 0.622 0.277 0.513 0.523 0.724 0.734
56 0.356 0.320 0.178 0.312 0.343 0.160 0.142 0.191 0.300 0.356
57 0.312 0.762 0.264 0.439 0.335 0.330 0.572 0.295 0.615 0.554
58 0.320 0.262 0.292 0.348 0.503 0.457 0.432 0.241 0.445 0.409
59 0.513 1.026 0.328 0.340 0.599 0.325 0.391 0.549 0.759 0.218
60 0.371 0.330 0.244 0.368 0.665 0.216 0.320 0.318 0.203 0.244
61 0.310 0.368 0.493 0.455 0.208 0.361 0.396 0.284 0.051 0.622
62 0.264 0.531 0.861 1.161 0.490 0.292 0.437 0.937 0.630 0.445
63 0.198 0.269 0.632 0.622 0.615 0.170 0.521 0.307 0.338 0.480
64 0.356 0.279 0.904 1.087 0.820 0.284 0.338 0.810 1.090 0.747
65 0.170 0.495 0.843 1.011 0.493 0.206 0.399 0.455 0.625 0.483
66 0.307 0.368 1.143 1.400 0.478 0.259 0.488 0.879 0.521 0.345
67 0.305 0.556 0.295 0.320 0.363 0.417 0.386 0.218 0.267 0.389
68 0.307 0.315 0.208 0.566 1.057 0.226 0.239 0.206 0.442 0.495
69 0.173 0.554 0.785 0.564 0.605 0.282 0.335 0.523 0.663 0.594
70 0.257 0.361 0.279 0.432 0.699 0.231 0.274 0.356 0.358 0.325
71 1.478 0.041 0.030 0.025 0.284 0.297 0.465 0.330 0.546 0.279
72 0.226 0.409 0.742 1.430 0.785 0.297 0.508 0.508 0.673 0.513
73 0.414 0.259 0.274 0.277 0.254 0.203 0.323 0.295 0.719 0.267
74 0.500 0.323 0.488 0.851 0.559 0.246 0.437 0.302 0.323 0.378
75 0.249 0.356 0.488 0.726 0.813 0.267 0.384 0.292 0.470 0.584
76 0.597 0.368 0.528 0.960 0.526 0.483 0.559 0.523 0.785 0.640
77 0.137 0.592 0.881 0.419 0.838 0.300 0.439 0.762 0.467 0.262
78 0.422 0.406 0.330 0.343 0.318 0.417 0.284 0.343 0.399 0.493
79 0.091 0.732 1.173 2.428 0.401 0.244 0.594 1.171 1.356 0.295
80 0.638 0.655 0.262 0.683 0.772 1.151 0.765 0.495 0.381 0.409
81 0.264 0.665 0.262 0.333 0.775 0.605 0.343 0.429 0.516 0.406
82 0.267 0.325 0.508 0.351 0.267 0.267 0.437 0.251 0.394 0.470
83 0.587 0.445 0.241 0.549 0.635 0.323 0.465 0.602 0.640 0.617
84 0.183 0.368 0.635 1.057 1.760 0.292 0.277 0.445 0.475 0.361




Full Text

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EFFECTS OF OYSTER SHELL SHAPE AND THICKNESS ON ABSORPTION OF ELECTRON BE AM, GAMMA RAY, AND X-RAY IRRADIATION By ARTHUR GRANT HURST, JR. A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLOR IDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2005

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Copyright 2005 by Arthur Grant Hurst, Jr.

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To my wife As hley, my parents, and my family for their continued support and encouragement

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iv ACKNOWLEDGMENTS I would like to extend thanks and gratitu de to my committee chairman and major advisor, Dr. Gary E. Rodrick. Without this guidance his work would not be possible. Thanks are due also to my supervisory co mmittee members, Dr. Ronald Schmidt and Dr. Sally Williams, for all their help and guidance in the completion of this research. I would like to express my appreciation to Carl Gi llis and Florida Accelerator Services and Technology of Gainesville, FL, for providing me the opportunity to perform research at this facility. Thanks are al so due to Food Technology Service, Inc. of Mulberry, FL, for allowing me the opportunity to perform research at its facility. I woul d also like to thank the National Center of Electron Beam Food Research at Texas A & M University of College Station, TX, for aiding us in our research and for the efficiency and consideration of the staff. Bill Leeming and Southern Cross Sea Farms, Inc. of Cedar Key, FL, deserve recognition for always providing top-quality clams. The efforts of fellow masters student Daniel Periu as well as all of my lab mates were invaluable in the completion of this project. In conclusion, I would like to thank my pa rents, Arthur and Darlene Hurst, for all of their love and support. I would also like to thank my wife, Ashley, for all of her love and support. Without her encouragement and support this research would not have been possible

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v TABLE OF CONTENTS page ACKNOWLEDGMENTS.................................................................................................iv LIST OF TABLES............................................................................................................vii LIST OF FIGURES.........................................................................................................viii ABSTRACT......................................................................................................................x ii CHAPTER 1 INTRODUCTION........................................................................................................1 2 REVIEW OF LITERATURE.......................................................................................4 Vibrio vulnificus...........................................................................................................4 Radiation...................................................................................................................... .6 Radiation Sources.........................................................................................................7 Radiation Dose..............................................................................................................8 Oysters........................................................................................................................ ..9 Clams.......................................................................................................................... 11 Mussels.......................................................................................................................1 2 3 MATERIALS AND METHODS...............................................................................14 Source of Oysters........................................................................................................14 Source of Clams..........................................................................................................14 Sources of Mussels.....................................................................................................15 Dosimeter Source and Reading..................................................................................15 Oyster, Clam and Mussel Measuring Protocol...........................................................15 Electron Beam and X-ray Protocol.............................................................................16 Gamma Irradiation Protocol.......................................................................................17 Statistics..................................................................................................................... .18 4 RESULTS AND DISCUSSION.................................................................................19 Oyster Irradiation with Electron Beam.......................................................................19 Oyster Irradiation with X-Ray....................................................................................26 Oyster Irradiation with Gamma..................................................................................32 Clam Irradiation with Electron Beam.........................................................................39

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vi Clam Irradiation with X-ray.......................................................................................45 Clam Irradiation with Gamma....................................................................................51 Mussel Irradiation w ith Electron Beam......................................................................58 Mussel Irradiation with X-ray....................................................................................65 Mussel Irradiation with Gamma.................................................................................71 5 SUMMARY AND CONCLUSIONS.........................................................................80 APPENDIX A OYSTER, CLAM, AND MUSSEL MEASUREMENTS..........................................82 Oyster Measurements.................................................................................................82 Clam Measurements...................................................................................................88 Mussel Measurement..................................................................................................94 Oyster Irradiation Dose Measurements....................................................................100 Clam Irradiated Dose Measurements........................................................................107 Mussel Irradiation Dose Measurements...................................................................113 B OYSTER, CLAM AND MUSSEL PICTURES.......................................................119 LIST OF REFERENCES.................................................................................................122 BIOGRAPHICAL SKETCH...........................................................................................126

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vii LIST OF TABLES Table page A-1 Oyster Weight Measurements in g (5/1/05).............................................................82 A-2 Oyster Dimension Measurements in cm (5/3/05)....................................................84 A-3 Oyster Thickness Measurements in cm (5/4/05)......................................................86 A-4 Clam Weight Measurements in g (4/29/05).............................................................88 A-5 Clam Dimension Measurement in cm (5/10/05)......................................................90 A-6 Clam Thickness Measurement in cm (5/12/05).......................................................92 A-7 Mussel Weight Measurement in g (5/12/05)............................................................94 A-8 Mussel Dimension Measurement in cm (5/20/05)...................................................96 A-9 Mussel Thickness Measurement in cm (5/22/05)....................................................98 A-10 Electron Beam irradi ated oysters in kGy...............................................................100 A-11 X-ray Irradiated Oysters in kGy.............................................................................102 A-12 Gamma Ray Irradiated Oysters in kGy..................................................................104 A-13 Electron Beam Irradiated Clams in kGy................................................................107 A-14 X-ray Irradiated Clams in kGy...............................................................................109 A-15 Gamma Ray Irradiated Clams in kGy....................................................................111 A-16 Electron Beam irradiated mussels in kGy..............................................................113 A-17 X-ray Irradiated Mussels in kGy............................................................................115 A-18 Gamma Ray Irradiated Mussels in kGy.................................................................117

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viii LIST OF FIGURES Figure page 4-1 The internal absorbed do se oyster shells compared to the external absorbed dose of the top shell of oysters after e xposure to electron beam at 1 kGy.......................19 4-2 The internal absorbed dose oyster shells as compared to the external absorbed dose of the top shell of oys ters after exposure at 3 kGy..........................................21 4-3 Percent external top shell dose absorbed internally in oyster shells compared to mean thickness of top shell of oysters ir radiated at doses of 1kGy and 3 kGy.......22 4-4 Percent external top shell dose absorbed internally in oyster shells as compared to curvature of top shell of the oysters irradiated at doses of 1kGy and 3 kGy.......23 4-5 Percent external dose absorbed internally in oyster shells compared to weight of oyster shells irradiated with electr on beam at doses of 1kGy and 3 kGy................25 4-6 The internal absorbed dose oyster shells as compared to the external absorbed dose of the top shell of oysters after exposure to x-ray at 1 kGy............................26 4-7 The internal absorbed dose of oyste r shells as compared to the external absorbed dose of the top shell of oys ters after exposure to x-ray at 3 kGy............28 4-8 Percent external shell dose absorbed internally in oyster shells compared to thickness of oyster shells i rradiated at doses of 1kGy and 3 kGy with x-ray..........29 4-9 Percent external top shell dose absorbed in ternally in oyster shells compared to curvature of oyster shells irradiated at doses of 1kGy and 3 kGy with x-ray at......30 4-10 Percent external top shell dose absorbed internally in oyster shells compared to weight of top shell of oyst ers irradiated at doses of 1kGy and 3 kGy with x-ray....31 4-11 The internal absorbed dose oyster shells as compared to the external absorbed dose of the top shell of oysters after exposure to gamma at 1 kGy.........................33 4-12 The internal absorbed dose of oyste r shells as compared to the external absorbed dose of the top shell of oyste rs after exposure to gamma at 3 kGy at.....34 4-13 Percent external shell dose absorbed internally in oyster shells compared to thickness of oyster shell irra diated at doses of 1 kGy and 3 kGy with gamma.......35

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ix 4-14 Percent external top shell dose absorbed internally in oyster shells compared to curvature of oyster shells irradiated at doses of 1kGy and 3 kGy with gamma at...36 4-15 Percent external top shell dose absorbed internally in oyster shells compared to weight of oyster shells irradiated at doses of 1kGy and 3 kGy with gamma...........37 4-16 The internal absorbed dose clam she lls as compared to the external absorbed dose of the top shell of clams after e xposure to electron beam at 1 kGy at............40 4-17 The internal absorbed dose clam she lls as compared to the external absorbed dose of the top shell of clam s after exposure at 3 kGy at........................................41 4-18 Percent external top shell dose absorbed internally in clam shells compared to thickness of clam shells irradiated w ith electron beam at 1kGy and 3 kGy............42 4-19 Percent external top shell dose absorbed internally in clam shells compared to curvature of clam shells irradiated with electron beam at 1kGy and 3 kGy............44 4-20 Percent external top shell dose absorbed internally in clam shells compared to weight of clam shells irradiated at dose s of 1kGy and 3 kGy with electron beam..45 4-21 The internal absorbed dose clam she lls as compared to the external absorbed dose of the top shell of clams af ter exposure to x-ray at 1 kGy..............................46 4-22 The internal absorbed dose of clam sh ells as compared to the external absorbed dose of the top shell of clams af ter exposure to x-ray at 3 kGy..............................47 4-23 Percent external top shell dose absorbed internally in clam shells compared to thickness of clam shells irradiated at doses of 1kGy and 3 kGy with x-ray............49 4-24 Percent external top shell dose absorbed in ternally in clam shells as compared to the curvature of clam shells irradiated at doses of 1kGy and 3 kGy with x-ray......50 4-25 Percent external top shell dose absorbed internally in clam shells compared to weight of clam shells irradiated at doses of 1kGy and 3 kGy with x-ray................51 4-26 The internal absorbed dose clam she lls as compared to the external absorbed dose of the top shell of clams af ter exposure to gamma at 1 kGy...........................52 4-27 The internal absorbed dose of clam sh ells as compared to the external absorbed dose of the top shell of clams af ter exposure to gamma at 3 kGy...........................53 4-28 Percent external top shell dose absorbed internally in clam shells compared to thickness of clam shells irradiated at doses of 1 kGy and 3 kGy with gamma........55 4-29 Percent external top shell dose absorbed internally in clam shells compared to curvature of clam shells irradiated at doses of 1kGy and 3 kGy with gamma at.....56

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x 4-30 Percent external top shell dose absorbed internally in clam shells compared to weight of clam shells irradiated at doses of 1kGy and 3 kGy with gamma.............57 4-31 The internal absorbed dose mussel she lls as compared to the external absorbed dose of the top shell of mussels afte r exposure to electron beam at 1 kGy.............58 4-32 The internal absorbed dose mussel she lls as compared to the external absorbed dose of the top shell of musse ls after exposure at 3 kGy........................................60 4-33 Percent external top shell dose absorbed internally in mussel shells compared to thickness of mussel shells irradiated w ith electron beam 1kGy and 3 kGy.............61 4-34 Percent external top shell dose absorbed internally in mussel shells compared to curvature of mussel shells irradiat ed at doses of 1kGy and 3 kGy..........................62 4-35 Percent external top shell dose absorbed internally in mussel shells compared to weight of mussel shells irradiated at 1kGy and 3 kGy with electron beam.............64 4-36 The internal absorbed dose mussel she lls as compared to the external absorbed dose of the top shell of mussels af ter exposure to x-ray at 1 kGy ..........................65 4-37 The internal absorbed dose of musse l shells as compared to the external absorbed dose of the top shell of mu ssels after exposure to x-ray at 3 kGy...........67 4-38 Percent external top shell dose absorbed internally in mussel shells compared to thickness of mussel shells irradiated at doses of 1kGy and 3 kGy with x-ray.........68 4-39 Percent external top shell dose absorbed internally in mussel shells compared to curvature of mussel shells irradiated at doses of 1kGy and 3 kGy with x-ray.........69 4-40 Percent external top shell dose absorbed internally in mussel shells compared to weight of mussel shells irradiated at doses of 1kGy and 3 kGy with x-ray.............70 4-41 The internal absorbed dose mussel she lls as compared to the external absorbed dose of the top shell of mussels af ter exposure to gamma at 1 kGy ......................72 4-42 The internal absorbed dose of musse l shells as compared to the external absorbed dose of the top shell of mu ssels after exposure to gamma at 3 kGy........73 4-43 Percent external top shell dose absorbed internally in mussel shells compared to thickness of mussel shells irradiated at 1 kGy and 3 kGy with gamma at...............74 4-44 Percent external top shell dose absorbed internally in mussel shells compared to curvature of mussel shells irradiated at doses of 1kGy and 3 kGy with gamma.....75 4-45 Percent external top shell dose absorbed internally in mussel shells compared to weight of mussel shells irradiated at doses of 1kGy and 3 kGy with gamma..........77

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xi B-1 Picture of oysters with dosimeter envelopes placed on them (6/8/05)...................119 B-2 Picture of clams with dosimeter envelopes placed on them (6/8/05).....................120 B-3 Picture of mussels with dosimeter envelopes placed on them (6/8/05).................121

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xii Abstract of Thesis Presen ted to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science EFFECTS OF OYSTER SHELL SHAPE AND THICKNESS ON ABSORPTION OF ELECTRON BEAM, GAMMA RAY, AND X-RAY IRRADIATION By Arthur Grant Hurst, Jr. December 2005 Chair: Gary E. Rodrick Major Department: Food Science and Human Nutrition The overall objective of this research wa s to determine the effects of shape and thickness on the absorption of electron beam, gamma ray and x -ray irradiation levels in raw oysters, clams and mussels. Groups of 100 oysters, 100 clams and 100 mussels were shucked of their meats and measured for dime nsions and thickness. Wild Apalachicola oysters, farm raised Cedar Key clams and farm raised mussels from China were used for this research. The oysters, clams and mussels were divided up into groups of 50, attached with 3 film dosimeter strips each and irradiated at doses of 1 kilogray (KGy) and 3 kilograys (KGy). After irradi ation the dosimeters were read using a spectrophotometer to determine the internal and external doses. Electron beam irradiation had the least unifo rm dose of the thre e sources. X-ray irradiation had a more uniform dose than el ectron beam. Gamma ray irradiation had the most uniform dose of the three doses. Oyst ers had a wider range of thicknesses and dimensions than the clams and mussels. Clams had a smaller range of thicknesses and

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xiii dimensions than the oysters, but the mussels had the smallest range of thicknesses and dimensions. The electron beam and x-ray so urces also showed signs of a concentration of irradiation within the she ll. In both of the sources th e internal absorbed dose was greater than the external or given dose. There are statistical differences between th e internal and external doses with all three types of irradiation. Statistical analysis showed differences in the amount of external doses absorbed in ternally between electron beam, x-ray and gamma ray. Observations suggest that the thicknesses, cu rvatures and weights of the shells do not independently have a significant effect on the amount of irradiation absorbed with in the shell. The oysters also had the least unifo rm internal dose absorp tion. Internal clam doses were more uniform than the internal oys ter doses but not as uniform as the internal mussel doses.

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1 CHAPTER 1 INTRODUCTION Oysters, clams and mussels are of great importance to those who work with the shellfish industry and those who consume th em. For many, these bivalve shellfish are a delicacy and for others a source of liveli hood. However, these bivalve shellfish have received much criticism in the past five years for their potential to cause disease and even death. The illnesses and deaths are primar ily due to the marine bacteria genera Vibrio especially V. vulnificus and V. parahemolyticus (Tamplin et al., 1982). Both of these organisms can be fatal, when cons umed by at risk individuals. Vibrio vulnificus is responsible for approximately 85 hospitalizations and approximately 35 deaths per year in the United States (Centers for Disease Control and Prevention [CDC], 2003). Certain individuals are at higher risk for this disease and likely to become infected from these organisms. At risk individuals include individuals who suffer from a compromised immune system, cirrhosis, diabetes, acqui red immunodeficiency syndrome, cancer, hemachromatosis or liver disease (Blake et al ., 1979). This group of at risk individuals makes up a large number of potential victims that has been estimated to be as large as 1015 million in the USA. In light of the morbidity and mortality concerns of these Vibrio diseases transmitted to at risk individuals by c onsuming raw oysters and clams, the shellfish industry is regulated to reduce or eliminat e the public health risk of Vibrio Efforts to reduce the associated morbidity and mortality from raw oyster consumption have led to increased regulation of shellfish waters as well as in creased efforts to inform the public through

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2 public bulletins and mandatory safety warnings in Florida, Louisiana and Texas. Despite the efforts of increased regulation and informa tion, the health concern still persists. This has led regulatory authorities to issue new re gionally specific food safety mandates that pose significant historical changes in oyster commerce. The mandate (Food and Drug Administration [FDA], 2003) calls for imme diate compliance goals before the end of 2004 and additional, more stringent goals before the end of 2006. The goals include implementation of new, innovative post-harvest treatments to reduce specific bacterial loads on raw oyster products. The regulatory expectations call fo r technology that has not been proven both in terms of food safety or market acceptance. Processing aids (e.g., depuration, relaying, freezing, pressure and irra diation) have been investigated with respect to reducing levels of V. vulnificus and V. parahemolyticus (Blogoslowski and Stewart, 1983; Motes and DePaola, 1996; Mest ey and Rodrick, 2003; Be rlin et al., 1996; Dixon, 1992). Irradiation of oysters is a processing technique which has promise for reducing the safety concern of these organisms. While irradiation has not yet been approved for seafood including oysters, irradiation of oysters has been investigated for decades. Vibrio is destroyed by irradiation. K ilgen et al. (1988) assessed shellstock oysters and showed that all Vibrio pathogens were significantly reduced to undetectable levels at a dose of 1 kGy. Although the Vibrio threat can be reduced or el iminated through irradiation many obstacles must be overcome before it can be put into practice. Perhaps the biggest obstacle to overcome is the obstruction and lack of uniformity regarding absorption through th e shell into the meat of the oyster. Dixon (1996) found that dosimeters placed inside oyster shells r eceived approximately half of the calculated

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3 dose that was calculated by the irradiation faci lity. The dose of radi ation absorbed by the meat is affected by the natural physical barrier of the shell. Shells may vary greatly in size, thickness, and shape so abso rption may vary even from oyster to oyster. In order for irradiation to be a viable op tion in the shellfish industry th e differences in oyster shells size, thickness, and shape must be considered. The overall objective of this research was to compare and contrast the percentage of absorption of irradiation from a ga mma ray source, electron beam and x-ray irradiation. The specific objectives of this research were to (1) examine the differences in absorbed dose of irradiation between the external top and internal secti ons of the shells of oysters, clams and mussels; (2) compare and contrast the absorpti on of irradiation in three different types of shellfish; (3) compar e the thickness and curvature of the shells to the internal dose.

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4 CHAPTER 2 REVIEW OF LITERATURE Vibrio vulnificus A public health risk exists for certain high risk individuals who consume raw or undercooked oysters and clams. Crassostrea virginica the American oyster and Mercenaria campechiensis hard-shelled clam have been implicated in several foodborne outbreaks (Blake et al., 1980; Blake, 1983; DuPont, 1986). Many different bacterial and viral agents such as Vibrio Salmonella Shigella Hepatitis virus and Norwalk virus have been isolated from shellfish (Blake et al., 1980). Although all of the organisms can cause problems in oysters and clams Vibrio is the most serious organism in shellfish. V. vulnificus is a Gram negative, halophilic rodshaped bacterium that is found in estuarine and marine environm ents (Blake, 1983; DuPont, 1986). The U.S. Gulf Coast is the most common place to find V. vulnificus (Tamplin et al., 1982), yet V. vulnificus has been isolated from the Atlantic Coast and Pacific Coast (Oliver et al., 1983; Kelly and Stroh, 1988). Both salinity and water temperatur e play a important role in the detection of V. vulnificus Levels of V. vulnificus are much higher during the warmer summer months and lower in waters with salin ities higher than 35 ppt (Kelly, 1982). Vibrio vulnificus is a ubiquitous marine and estuar ine microorganism that can be found throughout the world. This is considered natu rally occurring organi sm whose presence in the environment is not related to fecal pollution (Tamplin et al., 1982). Infection by V. vulnificus arises from the ingestion of raw or inadequately cooked oysters or clams or by exposure of wounds to contaminated water. A primary septicemia

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5 results from ingestion of V. vulnificus and is accompanied by gast roenteritis, chills, and fever. Individuals who become infected through a wound show symptoms of rapid swelling erythema around the wound, as well as fever and chills (Blake et al., 1980). Wound infections can also cause myositis, severe cellulites and are like ly to lead to gas gangrene (Klontz et al., 1988). Infections by V. vulnificus are onset rapidly with a median incubation period of approximately 12-16 hours (Blake et al., 1980). Vibrio vulnificus infections can be life threatening. Approximately 50% of patients who develop primary septicemia die (Morris and Black, 1985). In patients developi ng hypotension within 12 hours after hospital admission the mortality rate can be as high as 90% (Klontz et al., 1988). After primary septicemia sets in, many patients begin to de velop secondary lesions on their extremities that can result in necrotizing vasculitis in th e muscles, which often result in amputations (Howard et al., 1986). Several epidemiol ogical studies have been conducted which suggest that a relationship between se veral preexisting conditions and primary septicemia. Cirrhosis, diabetes, hemochromatosi s, kidney failure, liv er and iron disorders and any other immunocompromised conditions may cause individuals to be at risk (Blake et al., 1979; Tacket et al., 1984). The effect of V. vulnificus on at risk individuals has led regulatory authorities and industr y to investigate ways to redu ce or eliminate the impact of this organism on the public. Since 1980, the shellfish regulatory agencies and industry have put forth a strong effort to reduce the health risk related to oysters and clams. Dry cold storage is the current accepted practice for storage and ha ndling of oysters. Oysters are harvested, slightly cleaned, culled and either placed in croaker sacks or wa x boxes and stored at

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6 refrigeration at 34-36F in the dry cold storage method (Dixon, 1996). Bacterial reduction and shelf life extension are not ach ieved by this method. This ineffective method has led industry and regulatory authorit ies to look for innovative methods such as irradiation. Irradiation is an effective method in reducing V. vulnificus in oysters. When a large enough dose of irradiation is applied the bacter ia are reduced. Low doses of irradiation are effective in significantly reducing V. vulnificus in shell stock oysters (Dixon, 1992). The potential for irradiation to reduce V. vulnificus has led irradiation of shellfish to be investigated. Radiation Radiation is the movement of energy fr om a source through matter or space. Sound, light, microwaves, and a wide range of other forms of energy are all forms of radiation. Ionizing and non-ioni zing radiation are the main two irradiation categories of Non-ionizing radiation, such as visible light and microwaves lacks the energy to remove electrons from the orbit of at oms. Ionizing radiation can in teract with atoms and cause electrons to become excited or move from a lower energy level to a higher energy level. When significant ionizing radia tion is present the electron can be ejected from the atom. Electron separation from the atom causes i onization, creating a posit ive or negative ion (Urbain, 1986). Once the elec tron is free from the atom, it can interact with other materials and cause chemical structure change s in the material. In the case of food irradiation, these chemical structure changes occur within the microorganisms present in the food, cause the microorganisms damage and eventually deat h (Elias and Cohen, 1983). Death occurs in microorganisms either by the radiation inter acting directly with cell components or with adjacent molecules in the cell. Radiation damage to the cell can

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7 be caused directly by the ionizing ray or by free radicals,( H a nd OH,) created by the breakdown of water. The radicals, (prima rily OH) creates si ngle strand and double strand DNA breaks in the genetic material Single and double strand breaks in DNA occur due to chemical damage to the pur ine bases, pyrimadine bases and deoxyribose sugar (Farkas, 2001). If the genetic material is not repaired then the cell cannot produce crucial materials from the genetic mate rial and will die (G rez et al., 1983). Radiation Sources Three types of ionizing radi ation, gamma rays, x rays and electrons, are used in food irradiation. The most prev alent form of ionizing radiatio n used in food irradiation is the use of gamma rays. In food irradi ation processing, two sources, Cobalt and Cesium, are used for producing gamma ra ys. Decay of the unstable radioactive nucleus of Cobalt and Cesium cause ga mma rays to be produced (Urbain, 1986). Cobalt produces two gamma rays with en ergy levels of 1.17 million electron volts (MeV) and 1.33 MeV. Cesium produces on ly one gamma ray with an energy level of 0.66 MeV. Neither of these sources have the potential to pr oduce radioactive food. For significant radioactivity to be imparted into food energy levels larger than 15 MeV must be used. The half-life of Cobalt is 5.3 years. Cesium however has a halflife of 30.2 years. Gamma rays produ ced by Cobalt and Cesium have good penetrating power, but can not be turned on and off. They are always producing radiation. Containment and storage to prev ent environmental contamination are a major concern with these two sources. Both Cobalt and Cesium are generally approved by the FDA in food products approved for irradiation (CFR, 1994). Machine source electron beams and X-rays are also used in food irradiation processing, yet these are not as widely used as gamma rays. The energy levels for both

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8 of these sources also are not large enough to convey radioact ivity into the food. Electron beams must have energy levels of less than 10 MeV and X-rays must have energy levels less than 10 MeV to be allowe d in the United States (21CFR 179). Electron beams can be efficiently created in high doses in a shor t amount of time and there is not a constant radioactive source that must be contained. With electr on beam machine sources the radiation can be turned on and off, but electr ons do not penetrate as well as gamma rays. X-rays have greater penetrating power and can be turned on and off therefore contamination is less of an issue. However, production of x-rays is not very efficient. Radiation Dose The nomenclature used to determine radia tion dose have changed over time. In older literature the rad was us ed as the unit for radiation dose delivered to a product or radiation dose absorbed. One rad is equal to 100 ergs of absorbed energy per gram. Current literature mostly uses the Internationa l System of Units (SI) unit of Gray (Gy). One Gray is equal to 100 rads and 1 joul e of energy absorbed per kilogram of food (Urbain, 1986). The Food and Drug Admini stration (FDA) has approved several foods at different doses mostly ra nging from 1 kGy to 7 kGy. Fr esh foods are approved for 1 kGy to delay maturation, all f oods are approved at 1 kGy to prevent insect contamination, Poultry is approved at 3 kGy to reduce pat hogens, fresh red meat is approved at 4.5 kGy and frozen red meat is approved at 7 kGy to reduce pathogens (Henkel, 1998) by the FDA and the U.S. Department of Agriculture Food Safety Inspection Service (FSIS). All of the doses are rather low. The only excep tion is spices which are approved up to 30 kGy (Henkel, 1998). One major concern with oysters, clams, mu ssels and other bivalve shellfish is the lack of uniformity in the dose. The desire d target area for the ra diation, the meat, is

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9 shielded by a shell that may vary greatly in thickness, conformation and shape. This shell may reduce the dose being applied to the food. This lack of uniformity creates a situation where researchers must either choose a ma ximum dose or a minimum dose as the focus (Stein 1995). In this situation the researcher selects a minimum dose (Dmin) based on the amount of radiation needed to achieve desired effects and a maximum dose (Dmax) where no extra undesirable effects ar e created (Stein 1995). The extent of dose absorbed may vary depending on a variety of factors. Di xon (1996) found that the dose calculated by Food Technology Services of Mulberry, FL, a gamma ray food irradiation facility, was twice the dose received by internal dosimete rs. The calculated dose given to the product may vary greatly from the dose that the meat of the product actually receives. Research of irradiation of shellfish is focused around tw o possible advantages. The first major advantage of irradiation is the deduction of pathogens such as Vibrio in the shellfish such as oysters and clams. The second major advantage is the possibility of increasing shelf life of shellfish such as mu ssels. The major disadvantage of irradiating shellfish is the increased cost of the process. Overall th e possibility of increasing the safety of shellfish with only sligh tly increased cost is very promising. Oysters Irradiation is a relatively new form of food processing compared to drying or heating. For nearly a century irradiati on has been studied for processing food. Strawberries were processed with irradiat ion in 1916 (Webb et al., 1987). Many types of food have been irradiated since then. Fruits, vegetables, meats, fish, shellfish as well as many other types of food have been irradiated. Bivalve shellfish, such as oysters, clams a nd mussels are one type of food that is currently being researched as a candidate for irradiation to reduce pa thogens. Irradiation

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10 of oysters has been studied since th e 1950s as a possible method of reducing V. vulnificus and as a method to extend shelf life. Gardne r and Watts (1957) used ionizing radiation to treat oyster meats at low doses of 630 ra ds (0.63 kGy), 830 rads (0.83 kGy) and 3500 rads (3.5 kGy). They observed that undesira ble oxidized and gra ssy odors developed respectively in raw and cooked irradiated oyster meats. Gardner and Watts (1957) concluded that irradiation would not be succ essful in oyster preservation due to the continuation of enzyme action even with dos es of 3500 rads (3.5 kGy) and 5C storage. In 1966, Novak and others irradiated canned oyster meats at 2 kGy. The irradiated and control oysters were stored on ice for 23 days and tested at 0, 7, 14, 21, and 23 days. A trained taste panel was used to determine th at irradiated oyster meats were adequate for up to 28 days and non irradiated oyster meats were acceptable only up to seven days (Novak et al., 1966). Slavin et al. (1966) conc luded that oyster meats optimally irradiated at 2 kGy and stored at 0.6C resulted in shel f life of 21 to 28 days. Metlitskii et al. (1968) showed that oysters irradiated at 5 kG y and stored at 2C have a 60 day shelf life. Liuzzo et al. (1970) studied the optimum dose that would extend shelf life and result in the least altera tion in food components of shucked oyster meats. They determined that a dose of 2.5 kGy would exte nd the shelf life of oyster meat to seven days on ice. Sensory quality of the irradiat ed meats was not signifi cantly different from the non irradiated meats until the seventh day. Liuzzo et al. (1970) also determined that doses above 1 kGy altered the B-vitamin retention, percent moisture, percent ash, glycogen content and soluble suga r content of oyster meats. Kilgen et al. (1988) examined shells tock oysters and showed that all Vibrio pathogens were significantly reduced to undetect able levels at a dose of 1 kGy. Doses of

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11 1 kGy were not lethal to oysters. There we re also no significant sensory changes at a dose of 1 kGy. Mallet et al. ( 1991) irradiated shellstock oys ters from Massachusetts and determined that the survival times of oyste rs through six days was not affected by doses of up to 2.5 kGy. Mallet et al. (1991) concl uded that doses of 2.5 kGy or lower produced a median shelf life of greater than 25 days. Also, Mallett et al. (1991) also used a trained taste panel to determine that oysters irradiated at doses up to 3 kGy were acceptable. Hepatitis A virus and rotavirus SA11 in oysters and clams were also studied by Mallett et al. (1991). A dose of 2 kGy gave a D10 value for hepatitis A virus and a dose of 2.4 kGy gave a D10 value for rotavirus Sa11. In contrast to Kilgen et al. (1988), Dixon (1992) showed that 1 3 kGy doses of gamma radiation stored at 4 C to 6C were not effective in significantly extending the shelf life of Florida shellstock oysters longer than the non irradiated controls. In addition, Rodrick and Dixon (1994) found that the bacterial levels of V vulnificus fecals and overall bacteria were reduced by about 2 logs with doses of 1 kGy and 3 kGy. But this reduction only lasted a few days before the count s started to rise again to an even greater number than the initial amount. Also, in contrast to previous work, the shelf life for these oysters was not significan tly extended as claimed by Mallet et al. (1991). Clams Clams have also been studied with respect to irradiation as a possible method to reduce V. vulnificus or extend shelf life. Nick erson (1963), studied irradiation of clams and determined that clam meats had a shelf lif e of 28 days with a dos e of 4.5 kGy. Also, at doses up to 8.0 kGy Nickerson (1963) showed that irradiated clam meats stored at 6C for 40 days showed no detectable differences fr om non-irradiated clam meats. Slavin et al. (1963) also found that 4.5 kGy irradiated clam s stored at 6C were equal in quality to

PAGE 25

12 non irradiated clam meats. A taste panel was used by Connors and Steinberg (1964) to determine that clam meats irradiated at 2.5 kGy to 5.5 kGy were not significantly different from non irradiated clam meats. Yamada and Amano (1965) determined the optimum dose range to be 100-450 krads (0.1-0.4 5 kGy) to obtain a shelf life of four weeks at 0C-2C in Venerupis semiddecus sata clams. Carver et al. (1967) determined that shucked surf clam meats, Spisula solidissima air packed in plastic pouches have an optimum dose of 450 krads with a shelf life of 50 days at 0.6C. Non treated clam meats have a shelf life of 10 days at 0.6C. Carver et al. (1967) also determined that clams treated with doses of 100 200 krads have a sh elf life of 40 days at 0.6C. Harewood et al (1994) evaluated the effects of gamma radiation on bacterial and viral loads as well as shelf life in Mercenaria mercenaria hard shell clams. Radiation D10 values were 1.32 kGy for total coliforms, 1.39 kGy for fecal coliforms, 1.54 kGy for E. coli 2.71 kGy for C. perfringens and 13.5 kGy for F-coliphage. Mussels Irradiation of Mussels has been studied as well though to a lesser extent than have clams and oysters. Irradiation of mussels is of concern due to the possibility of increasing shelf life. Lohaharanu et al. (1972) examined shucked mussel meats and determined that the optimum dose of irra diation was 150-250 krads (0.15-0.25 kGy). The shelf life for the irradiated mussels were six weeks at 3 C and the shelf life for the nonirradiated mussels was three weeks at 3 C. Since mussels are not very susceptible to V. vulnificus and are generally eaten cooke d irradiation of mussels has not been researched to the degree that clams and oyste rs have. Extension of shelf life is one possible benefit of irradiating oysters however.

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13 Oysters, clams and mussels only make up a small part of the body of research of food irradiation. However, ir radiation of oysters, clams and mussels may prove to be important in providing a safe way of producing products which are safer for the consumer and have a longer shelf life.

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14 CHAPTER 3 MATERIALS AND METHODS This research included examination of oys ters, clams, and mussels for differences and similarities between shape, weight a nd size. The absorption of gamma ray and electron beam irradiation in oys ters, clams, and mussels were compared and contrasted. Also this research included analyzing the sh ape, weight and size of the oysters, clams, and mussels and their shells. Source of Oysters Florida shellstock oysters were used for anal ysis in this research. The source of the oysters used in this analysis was Leavins Seafood, Inc. of Apalachicola, FL. Summer oysters were harvested by Leavins Seafood, Inc. from approved shellfish harvesting waters in the Apalachicola area. Leavins delive red the oysters to us at the Interstate 10 Agricultural Inspection Station in Live Oak, FL via refrigerated truck. The oysters were transported on ice from Live Oak to the Un iversity of Florida in Gainesville, FL. Source of Clams Farm raised Florida hard shell clams were us ed in this research. The source of the clams used in this research was harvested by Southern Cross Sea Farms, Inc. The clams were harvested from approved shellfish harv esting waters in Cedar Key, FL. Southern Cross Sea Farms breads, raises and harvests clams in Cedar Key, FL. The clams were transported in coolers from Cedar Ke y to the University of Florida.

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15 Sources of Mussels Farm raised mussels from China were pur chased from Northwest Seafood, Inc. in Gainesville, FL and transported on ice to the University of Florida. The mussels were imported, frozen and distributed by Beaver Street Fisheries in Jacksonville, FL. Dosimeter Source and Reading FWT 60-00 dosimeter strips produced by Far West Technology Inc. of Goleta, CA were used to examine the dose of irradiation received in the inside and outside of the oyster, clams, and mussel shells. The Florida Accelerator Services Technology (FAST) facilitys dosimetery lab in Gainesville, FL was used to prepare and read all of the dosimeter strips used in this research. Th ese dosimeter strips were determined by Carl Gilus the dosimetry expert for FAST to be th e best fit for our dose, 1KGy to 3KGy, and the spectrophotometer equipment available to us at FAST. All of the FWT 60-00 dosimeter strips were read using the FWT-100 Radiachromic Reader at FASTs dosimetery lab produced by Far West Technology Inc. Oyster, Clam and Mussel Measuring Protocol Oysters, clams and mussels (100 of each) were irradiated and assessed. Each of the oysters, clams and mussels we re all measured following th is protocol. All of the shellstock shellfish were weighed and measured at the University of Florida, Department of Food Science and Human Nutrition. The meat s were shucked from the shells with a shucking knife, taking care to remove all of the meat. Both meat and shell were weighed, to the nearest tenth of a gram, individually for each shellfish. After weighing the meat was discarded. The top and bottom of the shell were also weighed individually and together. The shells were measured for thic kness, with calipers, at various locations over the shell at a variety of places mapping the shell. Upper and lower shell parts were

PAGE 29

16 compared to each other to determine the di fferences in weight between the upper and lower parts of the shell. Overall shell weight was compared to meat weight. The thickest and thinnest places were compared for each sh ell. Also, the thickness for each shell was averaged. The heights, at the highest part of the shell, of both the upper and lower parts of the shell were measured. In addition, the length of the upper and lower parts of each shell (at the longest part) was measured. The length and height for each shell was compared and contrasted. These comparisons were then used to determine the relative curvature of each shell. Electron Beam and X-ray Protocol The electron beam source for this resear ch was the National Center for Electron Beam Food Research (NCEBFR) facility at Texas A and M University at College Station, TX. The National Center for Electron Beam Food Research uses a 10 MeV Linear Accelerator to irradiate food for research and commercial us es. The accelerator is a linear Varian Accelerator in a Titan designed system. The X-ray source for this research was al so the National Center for Electron Beam Food Research facility (NCEBFR) at Texas A and M University at College Station, TX. The National Center for Electron Beam F ood Research uses a 10 MeV mechanical electron beam generator to produce electrons wh ich are accelerated into a dense metal to produce X-rays. A linear Varian Accelerator in a Titan designed system is focused on to a Tantalum alloy converter sheet to produce the x-rays. Doses of 1 KGy and 3 KGy, divided into th e two same groups as set in the Food Technology Service, Inc. Protoc ol, were also used at the NCEBFR electron beam and xray facility. One hundred oysters, 100 clams and 100 mussels used in this part of the research were shucked and cleaned prior to being sent to the NC EBFR facility. The

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17 oyster, clam and mussel shells were prepar ed with dosimeter envelopes following the same procedure used in the Food Technology Se rvice, Inc. Protocol (see pictures in Appendix B). The dosimetry lab was then used to fill all of the envelopes with dosimeter strips. The shell was then closed with a dr op of Elmers glue to prevent the shell from opening during irradiation. All of the shells were then placed into Ziploc bags and placed into a box with packing paper in -between the bags to protect the shells. The box of shells was then shipped via FedEx to the NCEBFR facility. The shells were then run through the electron beam till the desired dose was achieved as determined by the staff at NCEBFR. After irradiation the shells were boxed up by the staff NCEBFR and shipped via FedEx to the University of Florida. The shells were then taken to the FAST doismetry lab and the dosimeter strips were r ead. The entire procedure was then repeated for x-ray. Gamma Irradiation Protocol The gamma ray source for this research wa s Food Technology Servi ce, Inc. facility in Mulberry, FL. A Cobalt 60 (60Co) source was used at Food Technology to produce gamma rays for large scale commercial i rradiation. Food Technology was chosen over smaller gamma units for its industrial scale becau se it could be used to irradiate all of the oysters, clams and mussels at one time. Two different doses, 1 KGy and 3 KGy were used in this research. These are the doses that are currently being reviewed by the FDA for approval for use in seafood. Oyster, clam and mussel shells (100 of each ) were shucked and measured following the Oyster, Clam and Mussel Measuring Protocol. Three dosimeter envelopes were attached to each of the 300 shells using white carpent ers glue from Elmers Products Inc. of Columbus, OH. One envelope was attached to the outside of each of the upper shell.

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18 Another envelope was attached to the outside of the lower shell. The last envelope was placed in-between the two shells. Each of the envelopes was filled with one dosimeter strip at the FAST dosimetery lab. The she ll was then closed with a drop of white carpenters glue to prevent the shell from openi ng during irradiation. The shells were then equally divided into two boxes. The boxes of sh ells were transplanted to Food Tech and one box was irradiated at 1 KGy and the ot her at 3 KGy. After the desired dose was received the shells were taken back to Gainesville via car a nd read at the FAST dosimetery lab. Statistics All of the statistics for this research we re performed using Microsoft Excel XP. Paired t-test were performed on the entire external and internal dose data. All t-tests were performed with = 0.05. Linear regression models we re used in all of the figures to determine trend. An = 0.05 was also used for all of the linear regression models as well. Multiple linear regression models were performed in Microsoft Excel XP with the addition XLSTAT on all of the data for figures. All of the multiple linear regression models used = 0.05 as well.

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19 CHAPTER 4 RESULTS AND DISCUSSION Oyster Irradiation with Electron Beam The initial experiments for this resear ch were performed with electron beam irradiation of shucked oysters. Oysters were harvested on May 6, 2005 from approved shellfish harvesting waters in Apalachicola, FL and irradiated by electron beam at NCEBFR on June 8, 2005. The oysters were shucked, measured and loaded with dosimeter strips before irradiat ion. After irradiation the dosim eter strips that were placed on the top oyster shell, bottom oyster shell a nd in between the oyste r shells were read using spectrophotometery. 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 11.522.533.544.555.566.57 External Dose (Kgy)Internal Dose (Kgy) Figure 4-1. The internal absorbed dose shucked oyster shells as compared to the external absorbed dose of the top shell of sh ucked oysters after exposure to electron beam at 1 kGy at NCEBFR (6/8/05). Solid line shows linear regression of data with =0.05 (y = 0.2774x + 1.307 R2 = 0.1814).

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20 Figure 4-1 was created from the data in Table 10 (all Tables are located in Appendix A). Data in Figure 4-1 show the internal absorbed dose compared to the external top absorbed dose of the oyster shells irradiat ed at a dose of 1 kGy, as determined by the staff of NCEBFR. The in ternal doses absorbed by the strips range from 1.4 kGy to 3 kGy, have a median of 2.0 kGy and have a mean of 1.98 kGy. External top absorbed doses range from 1.6 kGy to 4.1 kGy, have a median of 2.3 kGy and have a mean of 2.46 kGy. The mean dose absorbed was larger than the 1kGy dose given as determined by NCEBFR for both external and in ternal dosimeters. In most cases the internal doses are smaller than the doses received by the top of the oys ter shells. However, in six of the thirty eight oysters irradiated at 1 kGy the internal absorbed dose is higher than the external top absorbed dose. External top dose mean is 0.47 kG y larger than the internal absorbed dose mean. Linear regression of the data shows a positive relationship between external dose and internal dose. This posit ive relationship is as expected. A higher external dose should produce a higher internal dose. The lin e does not fit the data well with an R2 value of 0.1814. The line only has an 18% fit with R2 values ranging from 0 to 1. External dose and internal dose are st atistically significantly different (P<0.05). Figure 4-2 was created from the data in Table 10. Data in Figure 4-2 show the internal absorbed dose compared to the exte rnal top absorbed dose of the oyster shells irradiated at a dose of 3 kGy, as determin ed by the staff of NCEBFR using p0hotometric technique. The internal doses absorbed by the strips range from 1.4 kGy to 5.3 kGy, have a median of 3.9 kGy and have a mean of 3.63 kGy. External top absorbed doses range from 1.9 kGy to 6.7 kGy, have a median of 4.3 kGy and have a mean of 4.18 kGy.

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21 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 11.522.533.544.555.566.57 External Dose (Kgy)Internal Dose (Kgy) Figure 4-2. The internal absorbed dose shucked oyster shells as compared to the external absorbed dose of the top shell of shuc ked oysters after exposure at 3 kGy at NCEBFR (6/8/05). Solid line shows linear regression of data with =0.05 (y = 0.698x + 0.7163 R2 = 0.5105). The mean dose absorbed was also larger than the 3 kGy dose given as determined by NCEBFR for both external and internal dosim eters. In six of the sixty two oysters irradiated at 3 kGy the internal absorbed dos e is higher than the ex ternal top absorbed dose. Having internal doses higher than th e applied external doses is a concentration phenomenon seen in both 1 kGy and 3 kGy oyste rs irradiated with electron beam. The cause of this phenomenon is currently not known. External top dose mean is 0.51 kGy larger than the internal absorbed dose mean. All of the oysters irradiated with electron beam cover a larger range of doses than was to be expected. The ex ternal doses (applied dose) cover a much larger range than we w ould expect. Not only doe s the internal dose vary, but the external dose varies greatly as we ll. This issue is an undesirable effect of electron beam. The doses in the oysters irradi ated at 3 kGy are much more wide spread than the doses of oysters irradiated at 1 kGy in Figure 4-1. Linear regression of the data

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22 shows a positive relationship be tween internal dose and external dose. The regression line for this data has a R2 value of 0.5105. External dose and internal dose are statistically signifi cantly different (P 0.05). 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 00.10.20.30.40.50.60.70.80.91 Mean Top Shell Thickness (cm)Internal/External Top Dose (%) Figure 4-3. Percent external t op shell dose absorbed internally in the oyster shells as compared to the mean thickness of the top shell of the oysters irradiated at doses of 1kGy and 3 kGy NCEBFR (6 /8/05). Solid line shows linear regression of data with =0.05 (y = 0.1846x + 0.777 R2 = 0.0226). Figure 4-3 was created from the data in Ta ble 3 and Table 10. Data in Figure 4-3 show the percent external top shell dose ab sorbed internally in the oyster shells as compared to the mean thickness of the top she ll of the oysters. For mean thickness of the top shell the range is 0.3 cm to 0.97 cm, the median is 0.46 cm and mean is 0.49 cm. The percent external top shell dose absorbed internally range is 132% to 43%, the median is 90% and the mean is 86.8%. Linear regression of this data shows a positive relationship between external dose absorbed internally and mean shell thickness. It was expected that the percent external top shell dose absorbed intern ally would decrease as the thickness increased, due to the

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23 limited penetration of electron be am irradiation to penetrate th icker material as well as thinner material. The data does not show th is relationship. However, this line does fit the data well with a R2 value of only 0.0226. Multiple linear regression of the data shows no significant relationship between external dose absorbed internally and mean shell thickness (P 0.05). It was expected that thickness would have a significant effect on the internal absorbed dose. This may be a result in the porous nature of the shell. If we were to measure thickness and dose on a microscopic level the results may differ. Also the effects of thickness on dose may be overshadowed by a more important unknown variable. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 00.10.20.30.40.50.60.70.80.91 Top Shell Curvature Internal/External Dose Figure 4-4. Percent external t op shell dose absorbed internally in the oyster shells as compared to the curvature of the top she ll of the oysters irradiated at doses of 1kGy and 3 kGy NCEBFR (6/8/05). Solid line shows linear regression of data with =0.05 (y = 0.2084x + 0.8182 R2 = 0.0117). Figure 4-4 was created from the data in Ta ble 2 and Table 10. Data in Figure 4-4 show the percent external top shell dose ab sorbed internally in the oyster shells as compared to the curvature of the top shell of the oysters. For curv ature of the top shell

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24 the range is 0.11 to 0.88, the median is 0.23 a nd mean is 0.24. The percent external top shell dose absorbed internally range is 132% to 43%, the median is 90% and the mean is 86.8%. The curvature of the oysters evaluated in th is research did not vary as greatly as first thought. The oysters appear to vary greatly in shape and size when examined by hand. The curvatures of the assessed oysters are similar. Linear regression shows a slight positive relationship be tween percentages of external dose absorbed internally and top shell curvature. The line does not have a good fit however the R2 value is only 0.0117. Multiple linear regression models of the data show no statistically significant relationship between curvature and percent of external dose absorbed internally (P 0.05). It was expected that curvature would have some sort of an effect on percentage of external dose absorbed internally. The lack of a significant effect may also be a result of a different variable overshadowing the effects of curvature. Or cu rvature may not have an effect on percentage of external dose bei ng absorbed internally when irradiated with electron beam. Figure 4-5 was created from the data in Ta ble 1 and Table 10. Data in Figure 4-5 show the percent external top shell dose ab sorbed internally in the oyster shells as compared to the weight of the top shell of th e oysters. For weight of the top shell the range is 19.8g to 41.5g, the median is 27.6g and mean is 27.9g. The percent external top shell dose absorbed internally range is 132% to 43%, the median is 90% and the mean is 86.8%.

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25 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 051015202530354045 Top Shell Wt (g)Internal/Top Dose Figure 4-5. Percent external t op shell dose absorbed internally in the oyster shells as compared to the weight of the top shell of the oysters irradi ated with electron beam at doses of 1kGy and 3 kGy NCEBFR (6/8/05). Solid line shows linear regression of data with =0.05 (y = -0.0032x + 0.9561 R2 = 0.0059). The oysters assessed in this research covere d a range weights. This can be seen in the top shell weights presented in this gra ph. Percentage of external dose absorbed internally is rather evenly dispersed betw een the weights assessed. Linear regression shows a slight negative relationship between percentages of external dose absorbed internally and top shell weight The line does not have a goo d fit which is evident by the R2 value of 0.0059. Multiple linear regression models show no statistically significant difference between top shell weight and percen tage of external dose absorbed internally (P 0.05). There were no expectations for wei ght, but it was a fact or that we hoped we could use to produce a graphical model or an equation to predict the percentage of external dose absorbed internally. However, for oysters irradiated with electron beam the factors we investigated did not have enough statistical effect to produce a statically significant model or equation.

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26 Oyster Irradiation with X-Ray The second set of experiments for this research was performed with x-ray irradiation of shucked oysters. Oysters were harvested from approved harvesting waters in Apalachicola, FL on May 6, 2005 and irradi ated with x-ray at NCEBFR on June 26, 2005. The oysters were shucked, measured, ir radiated with electron beam and loaded with dosimeter strips that were placed on th e top oyster shell, botto m oyster shell and in between the oyster shells before irradiation with x-ray. After irradiation with x-ray the dosimeter strips placed on the oysters we re read with using spectrophotometery. 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 11.522.533.544.555.56 External Dose (Kgy)Internal Dose (Kgy) Figure 4-6. The internal absorbed dose shucked oyster shells as compared to the external absorbed dose of the top shell of shuc ked oysters after expos ure to x-ray at 1 kGy at NCEBFR (6/26/05). Solid line s hows linear regression of data with =0.05 (y = -0.1084x + 1.7874 R2 = 0.0141). Figure 4-6 was created from the data in Table 11. Data in Figure 4-6 show the internal absorbed dose compared to the exte rnal top absorbed dose of the oyster shells irradiated by x-ray at a dose of 1 kGy, as determined by the staff of NCEBFR. The internal doses absorbed by th e strips range from 1.2 kGy to 2.6 kGy, have a median of

PAGE 40

27 1.5 kGy and have a mean of 1.59 kGy. Extern al top absorbed doses range from 1.3 kGy to 3.0 kGy, have a median of 1.8 kGy and have a mean of 1.85 kGy. The mean dose absorbed was larger than the 1kGy dose given as determined by NCEBFR for both external and internal dosimeters. Yet, the means are closer and the data is more consistent than the data presen ted for electron beam in Figure 4-1. Six of the thirty eight oysters irradiated with x-ray at 1 kGy exhibit an internal absorbed dose are higher than the external top absorbed dose. External top dose mean is 0.26 kGy larger than the internal absorbed dose mean. Linear regression of the data shows a very slight negative relationship between external dose and internal dose. Howe ver, the fit of the line to the data is not good with R2 value for the regression is 0.0041. External dose and internal dose are statistica lly significantly different (P 0.05). It was exp ected that these doses would be different due to xrays lower energy and penetration. Figure 4-7 was created from the data in Table 11. Data in Figure 4-7 show the internal absorbed dose compared to the exte rnal top absorbed dose of the oyster shells irradiated by x-ray at a dose of 3 kGy, as determined by the staff of NCEBFR. The internal doses absorbed by th e strips range from 1.2 kGy to 6.9 kGy, have a median of 3.8 kGy and have a mean of 3.82 kGy. Extern al top absorbed doses range from 1.4 kGy to 6.9 kGy, have a median of 4.2 kGy and have a mean of 4.12 kGy. The mean dose absorbed was also larger than the 3 kGy dose given as determined by NCEBFR for both external and internal dos es. In eight of the sixty two oysters irradiated at 3 kGy the internal absorbed dos e is higher than the ex ternal top absorbed dose. As with electron beam this concentr ation phenomenon is seen at doses of 1 kGy and 3 kGy. External top dose mean is 0.31 kG y larger than the in ternal absorbed dose

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28 mean. Linear regression of the data shows a positive relationship between internal dose and external dose at a 95% confidence interval and a good da ta fit with a R2 value of 0.6808. The doses in the oysters irradiated at 3 kGy are much more wide spread than the doses of oysters irradiated at 1 kGy. The oyste rs irradiated at 3 kGy with x-ray (Figure 47) and 3 kGy with electron beam (Figure 4-2) are more similar to each other than the oysters irradiated at 1kGy x-ra y (Figure 4-6) and 1 kGy with electron beam (Figure 4-1). External doses and internal doses of oysters irradiated with xray at 3 kGy are statistically significantly different (P<0.05). 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 11.522.533.544.555.566.57 External Dose (Kgy)Internal Dose (Kgy) Figure 4-7. The internal absorbed dose of shucked oyster shells as compared to the external absorbed dose of the top shell of shucked oysters after exposure to xray at 3 kGy at NCEBFR (6/26/05). So lid line shows linear regression of data with =0.05 (y = 0.9596x 0.1584 R2 = 0.6808). Figure 4-8 was created from the data in Ta ble 3 and Table 11. Data in Figure 4-8 show the percent external top shell x-ray dose ab sorbed internally in the oyster shells as compared to the mean thickness of the top she ll of the oysters. For mean thickness of the top shell the range is 0.3 cm to 0.97 cm, the median is 0.46 cm and mean is 0.49 cm. The

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29 percent external top shell dose absorbed internally range is 50% to 123%, the median is 90% and the mean is 91%. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 00.10.20.30.40.50.60.70.80.91 Mean Top Shell Thickness (cm)Internal/External Dose (%). Figure 4-8. Percent external t op shell dose absorbed internally in the oyster shells as compared to the mean thickness of the top shell of the oysters irradiated at doses of 1kGy and 3 kGy with x-ray NC EBFR (6/26/05). Solid line shows linear regression of data with =0.05 (y = -0.0916x + 0.9566 R2 = 0.0041). The data for percentage of external top shell dose absorbed internally is more tightly grouped for oysters irradiated with electron beam (Figure 4-3) than oysters irradiated with x-ray (Figure 4-8). Linear re gression of the data shows a slight negative relationship between the percenta ge of external dose absorbed internally and mean top shell thickness at a 95% confidence interval. The line for this data does not have a good fit with a R2 value of 0.0041. Multiple linear regr ession models show no statistically significant relationship (P 0.05) between the external doses absorbed internally and mean top shell thickness of oysters treated wi th x-ray. As with electron beam this was not expected.

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30 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 00.10.20.30.40.50.60.70.80.91 Top Shell Curvature Internal/External Dose (%). Figure 4-9. Percent external t op shell dose absorbed internally in the oyster shells as compared to the curvature of the top she ll of the oysters irradiated at doses of 1kGy and 3 kGy with x-ray at NCEBFR (6/26/05). Solid line shows linear regression of data with =0.05 (y = -0.3866x + 1.004 R2 = 0.0297). Figure 4-9 was created from the data in Ta ble 2 and Table 11. Data in Figure 4-9 show the percent external top shell x-ray dose ab sorbed internally in the oyster shells as compared to the curvature of the top shell of the oysters. For curv ature of the top shell the data range is 0.11 to 0.88, the median is 0.23 and mean is 0.24. The percent external top shell dose absorbed internally range is 50% to 123%, the median is 90% and the mean is 91%. The data from electron beam (Figure 4-4) and x-ray (Figure 4-9) is also very similar for curvature. The data for electron beam appears to be s lightly more tightly grouped than the data for x-ray. A slight negative relationship is shown between percentage of external dose absorbed inte rnally and top shell curvature with linear regression of at a confidence interval of 95%. However, with a R2 value of 0.0297 the line does not fit the data well. Multiple lin ear regression models of this data show no

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31 statistically significant rela tionship between percentage of external dose absorbed internally and top shell curvatur e at a (P<0.05). It was expect ed that there would be some effect of curvature on percentage of exte rnal dose absorbed internally. However, curvature may be overshadowed by another factor or just not have an effect at all. Figure 4-10 was created from the data in Table 1 and Table 11. Data in Figure 410 show the percent external t op shell dose absorbed internally in the oyster shells as compared to the weight of the top shell of th e oysters. For weight of the top shell the range is 19.8g to 41.5g, the median is 27.6g and mean is 27.9g. The percent external top shell dose absorbed internally range is 50% to 123%, the medi an is 90% and the mean is 91%. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 051015202530354045 Top Shell Wt (g)Internal/Top Dose Figure 4-10. Percent external top shell dose absorbed internally in the oyster shells as compared to the weight of the top shell of the oysters irradi ated at doses of 1kGy and 3 kGy with x-ray NCEBFR (6 /26/05). Solid line shows linear regression of data with =0.05 (y = 0.0094x + 0.65 R2 = 0.0383). Linear regression models of the data show a slight negative relationship between percentages of external dose absorbed internally and top sh ell weight. The line does not

PAGE 45

32 have a good fit however the R2 value is only 0.0059. No statically significant relationship (P 0.05) exists between exte rnal dose absorbed inte rnally and top shell weight in multiple linear regression models. None of the factors assessed for oysters irradiated with x-ray have a statically signi ficant effect on percentage of external dose absorbed internally. Oyster Irradiation with Gamma The third set of experiments for th is research was performed with 60Co gamma irradiation of shucked oysters. Oysters were harvested on May 6, 2005 from approved harvesting waters in Apalachic ola, irradiated with gamma at Food Technology Inc. on July 6, 2005. The oysters were shucked, measured, irradiated with electron beam, irradiated with x-ray and loaded with dosimet er strips before irradiation with gamma. After irradiation with gamma the dosimeter strips placed on the top oyster shell, bottom oyster shell and in between the oyster she lls were read using spectrophotometery. Figure 4-11 was created from data in Table 12. Data in Figure 4-11 show the internal absorbed dose compared to the exte rnal top absorbed dose of the oyster shells irradiated by gamma at a dose of 1 kGy, as determined by the staff of Food Technology Inc. The internal doses range from 1.2 kGy to 2.3 kGy, have a median of 1.8 kGy and have a mean of 1.77 kGy. External top ab sorbed doses range from 1.3 kGy to 3.1 kGy, have a median of 2.0 kGy and have a mean of 1.98 kGy. The range of data for gamma is smaller th an the range for electron beam or x-ray. The mean dose absorbed was larger than the 1kGy dose given as determined by Food Technology Inc. for both external and intern al dosimeters. For gamma the means are closer and the data is more consistent than the data presented for electron beam (Figure 41) or the data presented for x-ray in (Fi gure 4-6). However, the external doses and

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33 internal doses are statistical ly significantly different (P 0.05). The internal absorbed dose is not higher than the exte rnal top absorbed dose for a ny of the thirty eight oysters irradiated with gamma at 1 kGy. External top dose mean is 0.26 kGy larger than the internal absorbed dose mean. Linear regression of this data shows a positive relationship between external doses and internal doses at a 95% confidence interval. 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 11.522.533.544.555.56 External Dose (Kgy)Internal Dose (Kgy) Figure 4-11. The internal absorbed dose shucked oyster shells as compared to the external absorbed dose of the top she ll of shucked oysters after exposure to gamma at 1 kGy at Food Technology Inc. (7/6/05). Solid line shows linear regression of data with =0.05 (y = 0.6965x + 0.3874 R2 = 0.8077). Figure 4-12 was created from data in Table 12. Data in Figure 4-12 show the internal absorbed dose compared to the exte rnal top absorbed dose of the oyster shells irradiated by gamma at a dose of 3 kGy, as determined by the staff of Food Technology Inc. The internal doses absorbed range fr om 1.8 kGy to 5.2 kGy, have a median of 3.9 kGy and have a mean of 3.95 kGy. External top absorbed doses range from 1.8 kGy to 5.5 kGy, have a median of 4.2 kGy and have a mean of 4.13 kGy.

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34 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 11.522.533.544.555.56 External Dose (Kgy)Internal Dose (Kgy) Figure 4-12. The internal absorbed dose of shucked oyster shells as compared to the external absorbed dose of the top she ll of shucked oysters after exposure to gamma at 3 kGy at Food Technology Inc. (7/6/05). Solid line shows linear regression of data with =0.05 (y = 0.9254x + 0.1138 R2 = 0.9372). The data in Figure 4-12 follows the same layout as the electron beam (Figure 4-2) and the x-ray (Figure 4-7), but is more unifo rm and consistent. However, the external doses and internal doses are st atistically significantly different with a confidence level of 95%. Zero of the oysters irradiated with gamma at 3 kGy exhibit a internal absorbed dose higher than the external top absorb ed dose. Gamma does not exhibit the concentration phenomenon that affects electron beam and x-ray. External top dose mean is 0.18 kGy larger than the internal absorbed dose mean. Linear regression of the data shows a positive relationship between external dose and internal dose. With a R2 value of 0.9372 the regression line is almost a perfect f it. The data for gamma is more tightly grouped than the data for electron beam a nd x-ray. Gamma produces more consistent results than electron beam or x-ray in oysters.

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35 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 00.10.20.30.40.50.60.70.80.91 Mean Top Shell Thickness (cm)Internal/External Dose (%). Figure 4-13. Percent external top shell dose absorbed internally in the oyster shells as compared to the mean thickness of the top shell of the oysters irradiated at doses of 1 kGy and 3 kGy with gamma at Food Technology Inc. (7/6/05). Solid line shows linear regression of data with =0.05 (y = -0.0608x + 0.9641 R2 = 0.0176). Figure 4-13was created from data in Ta ble 3 and Table 12. Data in Figure 4-13 show the percent external top shell gamma dose absorbed internally in the oyster shells as compared to the mean thickness of the top she ll of the oysters. For mean thickness of the top shell the range is 0.3 cm to 0.97 cm, the median is 0.46 cm and mean is 0.49 cm. The percent external top shell dose absorbed internally range is 74% to 100%, the median is 95% and the mean is 93%. The shell thickness does not appear to affect the dose received in Figure 4-13. Data in Figure 4-13. are more tightly grouped than the data for electron be am (Figure 4-3) and the data for x-ray (Figure 4-8). A slight nega tive relationship exist between percentage of external dose absorbed internally and mean top shell thickness when linear regression models are ran with a 95% c onfidence interval. The line is not a good fit for the data

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36 with a R2 value of only 0.0176. Multip le linear regression models show no statistically significant relationship (P 0.05) between mean top shell thickness and percentage of external dose absorbed internally. It was expected that mean top shell thickness would have a negative relationship to percentage of external dose absorbed internally. The lack of a relationship may be caused by the use of macro measurements instead of micro measurements or thickness may be overshadow ed by other unknown factors. Oyster top shell thickness does not have a statistically significant relationship (P 0.05) to percentage of external dose absorbed internally for any of the three irradi ation sources tested. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 00.10.20.30.40.50.60.70.80.91 Top Shell Curvature Internal/External Dose (%). Figure 4-14. Percent external top shell dose absorbed internally in the oyster shells as compared to the curvature of the top she ll of the oysters irradiated at doses of 1kGy and 3 kGy with gamma at Food T echnology Inc. (7/6 /05). Solid line shows linear regression of data with =0.05 (y = -0.0055x + 0.9354 R2 = 6E05). Figure 4-14 was created from data in Tabl e 2 and Table 12. Data in Figure 4-14 show the percent external top shell gamma dose absorbed internally in the oyster shells as compared to the curvature of the top shell of the oysters. For curv ature of the top shell the range is 0.11 to 0.88, the median is 0.23 a nd mean is 0.24. The percent external top

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37 shell dose absorbed internally for gamma irradi ation range is 74% to 100%, the median is 95% and the mean is 93%. The data for the gamma (Figure 4-14) is more tightly grouped than the data for electron beam (Figure 4-4) or the data for x -ray (Figure 4-9). Lin ear regression at a 95% confidence interval shows an extremely small negative relationship between the percentage of external dose absorbed internal ly and top shell curvatur e. However, the fit of the line is horrible with a R2 value of 0.00006. Multiple linear regression models of the data show no statistically significant relationship (P 0.05) between percentage of external dose absorbed internally and top shel l curvature. As with electron beam and xray, curvature does not have a statistically significant (P 0.05) effect on the percentage of external dose absorbed internally in oysters irradiated with gamma. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 051015202530354045 Top Shell Wt (g)Internal/Top Dose Figure 4-15. Percent external top shell dose absorbed internally in the oyster shells as compared to the weight of the top shell of the oysters irradi ated at doses of 1kGy and 3 kGy with gamma Food Tec hnology Inc. (7/6/05). Solid line shows linear regression of data with =0.05 (y = -0.0024x + 1.0004 R2 = 0.0241).

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38 Figure 4-15 was created from data in Ta ble 1 and Table 12. Data in Figure 4-15 show the percent external top shell dose ab sorbed internally in the oyster shells as compared to the weight of the top shell of th e oysters. For weight of the top shell the range is 19.8g to 41.5g, the median is 27.6g and mean is 27.9g. The percent external top shell dose absorbed internally range is 74% to 100%, the median is 95% and the mean is 93%. Percentage of external dose absorbed inte rnally is rather evenly dispersed between the weights assessed. Linear regression show s a slight negative relationship between percentages of external dose absorbed in ternally and top shel l weight at a 95% confidence interval. The line does not have a good fit however the R2 value is only 0.0241. No significant relationship exists betwee n external dose absorbed internally and top shell weight in multiple linear regression models (P 0.05). Top shell weight does not have a statistically significant (P 0.05) effect on percentage of external dose absorbed internally in any of the thr ee irradiation sources examined. The external doses and internal doses are statistically significantly different (P<0.05) in oysters irradiated with electr on beam, x-ray and gamma at doses of 1 kGy and 3 kGy. This is to be expected due to the barrier effect of the oyster shell against irradiation. Top shell thickness, curvature a nd weight all have no significant effect on percentage of external dose absorbed internal ly for oysters irradiated at 1 kGy and 3 kGy with electron beam, x-ray and gamma. This was not expected, but as discussed above this may be an effect of macro measuremen t instead of micro m easurements or these factors may be overshadowed by a more impor tant unknown factor. Of the three sources the data for gamma is most tightly grouped. Oysters irradiated with gamma also have

PAGE 52

39 smaller ranges of data than electron beam and x-ray do. Gamma does not exhibit the concentration phenomenon that is seen in el ectron beam and x-ray. Because of these reasons gamma is the most promising irradia tion source for irradiating oysters on a large scale. Further experiments need to be performed. Large scale experime nts with pallets of hundreds of bushels of oysters would provide the data needed to examine how effective gamma is in industrial production. Further e xperiment with electron beam and x-ray are also needed. Electron beam and x-ray may be more promising for half shell oysters. Further research may add to the knowledge and direct how electron beam, x-ray and gamma can be used to efficiently irradiate oysters. Clam Irradiation with Electron Beam Electron beam was used to irradiate cl ams at NCEBFR as well. Clams were harvested on May 11, 2005 from Cedar Key and irradiated with electron beam on June 8, 2005. The clams were shucked, measured and loaded with dosimeter strips during the before irradiation. After irradiation the dos imeter strips placed on the top clam shell, bottom clam shell and in betw een the clam shells were read using spectrophotometery. Figure 4-16 was created using the data in Table 13. Data in Figure 4-16 show the internal absorbed dose compared to the exte rnal top absorbed dose of the clam shells irradiated at a dose of 1 kGy, as determined by the staff of NCEBFR. The internal doses absorbed by the strips range fr om 1.2 kGy to 2 kGy, have a median of 1.7 kGy and have a mean of 1.70 kGy. External top absorbed doses range from 1.5 kGy to 3.1 kGy, have a median of 2.1 kGy and have a mean of 2.12 kGy.

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40 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 11.522.533.544.555.56 External Dose (Kgy)Internal Dose (Kgy) Figure 4-16. The internal absorbed dose shucke d clam shells as compared to the external absorbed dose of the top shell of sh ucked clams after exposure to electron beam at 1 kGy at NCEBFR (6/8/05). Solid line shows linear regression of data with =0.05 (y = 0.0405x + 1.6096 R2 = 0.0061). The mean dose absorbed was larger than the 1kGy dose given as determined by NCEBFR for both external and in ternal dosimeters. In most cases the internal doses are smaller than the doses received by the top of the clam shells. However, in three of the forty five clams irradiated at 1 kGy the internal absorbed dose is higher than the external top absorbed dose. The external doses and internal doses are statistically significantly different (P 0.05). External top dose mean is 0.42 kG y larger than the internal absorbed dose mean. Linear regression of the data at a 95% confidence in terval shows a very small positive relationship exist between extern al doses and internal doses. However the fit of line to the data is not good with a R2 of 0.0061. The data for clams irradiated with electron beam at 1 kGy are more tightly grouped than the data for oysters irradiated with electron beam at 1 kGy.

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41 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 11.522.533.544.555.56 External Dose (Kgy)Internal Dose (Kgy) Figure 4-17. The internal absorbed dose shucke d clam shells as compared to the external absorbed dose of the top shell of sh ucked clams after exposure at 3 kGy at NCEBFR (6/8/05). Solid line show s linear regression of data with =0.05 (y = 0.9134x + 0.152 R2 = 0.8344). Figure 4-17 was created using the data in Table 13. Data in Figure 4-17 show the internal absorbed dose compared to the exte rnal top absorbed dose of the clam shells irradiated at a dose of 3 kGy, as determined by the staff of NCEBFR. The internal doses absorbed by the strips range from 1.5 kG y to 4.2 kGy, have a median of 3.7 kGy and have a mean of 3.50 kGy. External top ab sorbed doses range from 1.8 kGy to 4.6 kGy, have a median of 3.8 kGy and have a mean of 3.78 kGy. The mean dose absorbed was also larger than the 3 kGy dose given as determined by NCEBFR for both external and internal dos es. In nine of the fifty five clams irradiated at 3 kGy the internal absorbed dos e is higher than the ex ternal top absorbed dose. The concentration phenomenon is seen in clams irradiated w ith electron beam as well as oysters. However, the external dos es and internal doses are statistically significantly different (P<0.05). External top dose mean is 0.29 kGy larger than the

PAGE 55

42 internal absorbed dose mean. Linear regression of the data shows a positive relationship between external doses and internal doses w ith a 95% confidence interval. The line is a good fit with a R2 value of 0.3158. The tighter grouping of data for clams irradiated with electron beam than data for oys ters irradiated with electron beam may be a result of the more uniform shape and structure of the clams. Figure 4-18 was created using the data in Table 6 and Table 13. Data in Figure 418 show the percent external t op shell dose absorbed internally in the clam shells as compared to the mean thickness of the top she ll of the clams. For mean thickness of the top shell the range is 0.26 cm to 0.33 cm, the median is 0.29 cm and mean is 0.29 cm. The percent external top shell dose absorbed in ternally range is 50% to 125%, the median is 92% and the mean is 88%. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 00.050.10.150.20.250.30.350.40.450.5Mean Top Shell Thickness (cm)Internal/External Dose (%) Figure 4-18. Percent external top shell dose absorbed internally in the clam shells as compared to the mean thickness of the t op shell of the clams irradiated with electron beam at doses of 1kGy and 3 kGy NCEBFR (6/8/05). Solid line shows linear regression of data with =0.05 (y = 0.217x + 0.8137 R2 = 0.0005).

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43 Linear regression of the data shows a small positive relationship between the percentage of external dose absorbed intern ally and the mean top shell thickness at a 95% confidence interval. However, the line is not a g ood fit with a R2 value of only 0.0005. The percent of external top shell dose absorb ed internally covers a range of 75%. The percentages of doses received internally from the electron beam are not very uniform. Multiple linear regression models shows no significant relationship between the percent of external top shell dose abso rbed internally and the mean top shell thickness (P<0.05). As with oysters, thickness does not have a statistically significant effect (P 0.05) on the percentage of external dose absorbed intern ally in clams irradiat ed with electron beam. Figure 4-19 was created using the data in Table 5 and Table 13. Data in Figure 419 show the percent external t op shell dose absorbed internally in the clam shells as compared to the curvature of th e top shell of the clams. For curvature of the top shell the range is 0.26 to 0.39, the median is 0.33 and me an is 0.33. The percen t external top shell dose absorbed internally range is 50% to 125%, the median is 92% and the mean is 88%. The curvatures of the clams analyzed in this research are very uniform. A negative relationship exists, at confidence interval of 95%, between the per centage of external dose absorbed internally and th e top shell curvature when linear regression is applied to the data. However, with an R2 value of 0.0237 the line is not a good fit. In addition, multiple linear regression models of the data show no statistically significant relationship (P 0.05) between the percentage of external dos e absorbed internally and the top shell curvature. Like oysters top shell curvature was expected to a signi ficant effect on the percentage of external dose absorbed internal ly. The unexpected resu lt may be an effect

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44 of measuring techniques or a result of other factors overshado wing the effect of curvature on the percentage of external dose absorbed internally. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 00.10.20.30.40.50.60.70.80.91Top Shell CurvatureInternal/External Dose(%) Figure 4-19. Percent external top shell dose absorbed internally in the clam shells as compared to the curvature of the top she ll of the clams irradiated with electron beam at doses of 1kGy and 3 kGy NCEBFR (6/8/05). Solid line shows linear regression of data with =0.05 (y = -1.1461x + 1.2569 R2 = 0.0237). Figure 4-20 was created using the data in Table 7 and Table 13. Data in Figure 420 show the percent external t op shell dose absorbed internally in the clam shells as compared to the weight of the top shell of the clams. For weight of the top shell the range is 10.0g to 20.6g, the median is 13.0g and mean is 13.9g. The percent external top shell dose absorbed internally range is 50% to 125%, the median is 92% and the mean is 88%. Linear regression shows a positive relati onship between percentages of external dose absorbed internally and t op shell weight at a 95% confidence interval. The line does not have a good fit however the R2 value is only 0.0005. No statistically significant relationship (P 0.05) exists between exte rnal dose absorbed inte rnally and top shell

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45 weight in multiple linear regression models w ith a 95% confidence level. Like thickness and curvature, weight is not a statistically significant factor in determining the percentage of external dose absorbed internally in clam s irradiated with electr on beam. Other factors or thickness, curvature and weight must be examined in order to determine the factors that effect percentage of exte rnal dose absorbed internally. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 0123456789101112131415161718192021Top Shell Weight (g)Internal/External Dose (%) Figure 4-20. Percent external top shell dose absorbed internally in the clam shells as compared to the weight of the top shell of the clam irradiated at doses of 1kGy and 3 kGy with electron beam NCEBFR (6/8/05). Solid line shows linear regression of data with =0.05 (y = 0.217x + 0.8137 R2 = 0.0005). Clam Irradiation with X-ray Shucked clams were also i rradiated with x-ray for this research. Clams were harvested on May 11, 2005 from Cedar Key, irra diated with x-ray at NCEBFR on June 26, 2005. The clams were shucked, measured, ir radiated with electron beam and loaded with dosimeter strips before irradiation w ith x-ray. After irradi ation with x-ray the dosimeter strips placed on the top clam shell, bottom clam shell and in between the clam shells were read using spectrophotometery.

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46 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 11.522.533.544.555.56 External Dose (Kgy)Internal Dose (Kgy) Figure 4-21. The internal absorbed dose shucke d clam shells as compared to the external absorbed dose of the top shell of shucked clams after exposure to x-ray at 1 kGy at NCEBFR (6/26/05). Solid line s hows linear regression of data with =0.05 (y = 0.3976x + 1.0481 R2 = 0.3738). Figure 4-21 was created from the data in Table 14. Data in Figure 4-21 show the internal absorbed dose compared to the exte rnal top absorbed dose of the clam shells irradiated by x-ray at a dose of 1 kGy, as determined by the staff of NCEBFR. The doses absorbed internally range from 1.2 kGy to 3.0 kGy, have a median of 1.9 kGy and have a mean of 1.9 kGy. External t op absorbed doses range from 1.2 kGy to 4.2 kGy, have a median of 2.2 kGy and have a mean of 2.23 kGy. The mean dose absorbed was larger than the 1kGy dose given as determined by NCEBFR for both external and in ternal dosimeters. External doses and internal doses of clams irradiated at 1 kGy with x-ray are stat istically significantly different (P<0.05). In eight of the forty five clams irradiated with x-ray at 1 kGy the internal absorbed dose are higher than the external top absorbed dose. External top dose mean is 0.33 kGy larger

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47 than the internal absorbed dose mean. Ex ternal dose and internal dose have a positive relationship in linear regression models with a R2 value equal to 0.3738. 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 11.522.533.544.555.56 External Dose (Kgy)Internal Dose (Kgy) Figure 4-22. The internal absorbed dose of shucked clam shells as compared to the external absorbed dose of the top she ll of shucked clams after exposure to xray at 3 kGy at NCEBFR (6/26/05). So lid line shows linear regression of data with =0.05 (y = 0.6603x + 1.2588 R2 = 0.5929). Figure 4-22 was created from the data in Table 14. Data in Figure 4-22 show the internal absorbed dose compared to the exte rnal top absorbed dose of the clam shells irradiated by x-ray at a dose of 3 kGy, as determined by the staff of NCEBFR. The internal doses absorbed range from 1.8 kG y to 5.4 kGy, have a median of 4.0 kGy and have a mean of 4.05 kGy. External top ab sorbed doses range from 1.7 kGy to 6.3 kGy, have a median of 4.3 kGy and have a mean of 4.27 kGy. The mean dose absorbed was also larger than the 3 kGy dose given as determined by NCEBFR for both external and internal doses by more than 1kGy. In nine of the fifty five clams irradiated at 3 kGy the internal absorbed dose is higher than the external top absorbed dose. The external doses and in ternal doses are statistically significantly

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48 different (P<0.05). External top dose mean is 0.22 kGy larger than the internal absorbed dose mean. Linear regression of the data shows a positive relationship between external dose and internal dose at a 95% confidence interval. Data for clams irradiated with x-ray are more tightly grouped than oysters irradiat ed with x-ray. As discussed above the farm raised clams are more uniform shell and are more similar to each other than the wild oysters. Figure 4-23 was created from the data in Table 6 and Table 14. Data in Figure 423 show the percent external top shell x-ray dose absorbed intern ally in the clam shells as compared to the mean thickness of the top she ll of the clams. For mean thickness of the top shell the range is 0.26 cm to 0.33 cm, the median is 0.29 cm and mean is 0.29 cm. The percent external top shell dose absorbed in ternally range is 56% to 163%, the median is 94% and the mean is 93%. The data in Figure 4-23 are also very simila r to the data found Figure 4-18. Both xray and electron beam have similar spreads of percentage of external dose absorbed internally. Linear regression of the da ta shows a positive relationship between the percentage of external dose absorbed intern ally and the mean top shell thickness at a 95% confidence interval. However, the R2 value for this data is only 0.0064 meaning that the line is not a good fit for the data. Multiple li near regression models show no statistically significant relationship (P 0.05) between percentage of exte rnal dose absorbed internally and the mean top shell thickness. It was exp ected that thickness would have a negative relationship to percentage of external dose abso rbed internally. The lack of a relationship here may be due to the small range of thicknesses examined.

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49 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 00.050.10.150.20.250.30.350.40.450.5Mean Top Shell Thickness (cm)Internal/External Dose (%) Figure 4-23. Percent external top shell dose absorbed internally in the clam shells as compared to the mean thickness of the top shell of the clams irradiated at doses of 1kGy and 3 kGy with x-ray NC EBFR (6/26/05). Solid line shows linear regression of data with =0.05 (y = 0.7114x + 0.7226 R2 = 0.0064v). Figure 4-24 was created from the data in Table 5 and Table 14. Data in Figure 424 show the percent external top shell x-ray dose absorbed intern ally in the clam shells as compared to the curvature of th e top shell of the clams. For curvature of the top shell the range is 0.26 to 0.39, the median is 0.33 and me an is 0.33. The percen t external top shell dose absorbed internally range from 70% to 117%, have a median of 98% and have a mean of 96%. Curvatures of clam shell examined in th is research are very uniform. The clam shell curvatures are less dive rse than the oyster shells. A negative relationship is shown between percentage of external dose absorbed internally and top shell curvature in linear regression models with a confidence interval of 95% and a R2 value of 0.0006. However, multiple linear regression models show no statistically significant relationship (P 0.05) between percentage of external dose absorb ed internally and top shell curvature.

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50 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 00.10.20.30.40.50.60.70.80.91Top Shell CurvatureInternal/External Dose (%) Figure 4-24. Percent external top shell dose absorbed internally in the clam shells as compared to the curvature of the top she ll of the clams irradi ated at doses of 1kGy and 3 kGy with x-ray at NCEBFR (6/26/05). Solid line shows linear regression of data with =0.05 (y = -0.1797x + 0.9903 R2 = 0.0006). Figure 4-25 was created from the data in Table 4 and Table 14. Data in Figure 425 show the percent external t op shell dose absorbed internally in the clam shells as compared to the weight of the top shell of the clams. For weight of the top shell the range is 10.0g to 20.6g, the median is 13.0g and mean is 13.9g. The percent external top shell dose absorbed internally range is 70% to 117%, the median is 98% and the mean is 96%. Linear regression shows a positive relati onship between percentages of external dose absorbed internally and t op shell weight at a 95% confidence interval. The line does not have a good fit however the R2 value is only 0.0064. No statistically significant relationship (P 0.05) exists between exte rnal dose absorbed inte rnally and top shell weight in multiple linear regression model. As with electron beam irradiated clams, xray irradiated clams are not significantly a ffected by any of the factors we assessed.

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51 Further experiments examining a larger rang e thicknesses, curvatures and weight may provide different results. Measuring the shells microscopically may also provide different results. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 0123456789101112131415161718192021Top Shell Weight (g)Internal/External Dose (%) Figure 4-25. Percent external top shell dose absorbed internally in the clam shells as compared to the weight of the top shell of the clam irradiated at doses of 1kGy and 3 kGy with x-ray NCEBFR (6/26/05) Solid line shows linear regression of data with =0.05 (y = 0.7114x + 0.7226 R2 = 0.0064). Clam Irradiation with Gamma A 60Co gamma source was also used in the irradiation of shucked clams. Clams were harvested on May 11, 2005 from Ceda r Key, irradiated with gamma at Food Technology Inc. on July 6, 2005. The clams we re shucked, measured, irradiated with electron beam, irradiated with x-ray and loaded with dosimeter strips before irradiation with gamma. After irradiation with gamma the dosimeter strips placed on the top clam shell, bottom clam shell and in between the clam shells were read using spectrophotometery.

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52 Figure 4-26 was created from the data in Table 15. Data in Figure 4-26 show the internal absorbed dose compared to the exte rnal top absorbed dose of the clam shells irradiated by gamma at a dose of 1 kGy, as determined by the staff of Food Technology Inc.. The internal doses range from 1.4 kG y to 3.1 kGy, have a median of 1.8 kGy and have a mean of 1.88 kGy. External top ab sorbed doses range from 1.5 kGy to 3.3 kGy, have a median of 2.0 kGy and have a mean of 2.09 kGy. 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 11.522.533.544.555.56 External Dose (Kgy)Internal Dose (Kgy) Figure 4-26. The internal absorbed dose shucke d clam shells as compared to the external absorbed dose of the top shell of shucked clams after exposure to gamma at 1 kGy at Food Technology Inc. (7/6/05). Solid line shows lin ear regression of data with =0.05 (y = 0.6135x + 0.6042 R2 = 0.6179). The mean dose absorbed was larger than the 1kGy dose given as determined by Food Technology Inc. for both external and in ternal dosimeters. For gamma the means are closer than the means for electron beam or x-ray. The external doses and internal doses are statistically signifi cantly different (P<0.05) for cl ams irradiated at 1 kGy with gammas. For only one of the forty five clams ir radiated with gamma at 1 kGy the internal absorbed dose is higher than the external t op absorbed dose. External top dose mean is

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53 0.21 kGy larger than the internal absorbed dos e mean. Linear regression of the data shows a positive relationship between external dose and internal dose at a 95% confidence interval. The regression line is also a good fit with a R2 value of 0.6179. Figure 4-27 was created from the data in Table 15. Data in Figure 4-27 show the internal absorbed dose compared to the exte rnal top absorbed dose of the clam shells irradiated by gamma at a dose of 3 kGy, as determined by the staff of Food Technology Inc. The internal doses absorbed range fr om 1.5 kGy to 5.1 kGy, have a median of 4.3 kGy and have a mean of 4.24 kGy. External top absorbed doses range from 1.7 kGy to 5.2 kGy, have a median of 4.6 kGy and have a mean of 4.46 kGy. 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 11.522.533.544.555.56 External Dose (Kgy)Internal Dose (Kgy) Figure 4-27. The internal absorbed dose of shucked clam shells as compared to the external absorbed dose of the top she ll of shucked clams after exposure to gamma at 3 kGy at Food Technology Inc. (7/6/05). Solid line shows linear regression of data with =0.05 (y = 0.9134x + 0.152 R2 = 0.8344). The external doses and internal doses are statistically significantly different (P<0.05). None of the clams irradiated with gammas at 3 kGy have a internal dose higher than the external dose. As with oysters gamma does not show the effects of a

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54 concentration phenomenon. The external top dose mean is 0.22 kGy larger than the internal absorbed dose mean. Data for cl ams irradiated with gamma are more tightly grouped than data for clams irradiated with electron beam and x-ray. A positive relationship between external dose and internal dose is s hown by linear regression of the data at a 95% confidence interval. The regre ssion line is a good fit to the data with a R2 value equal to 0.8344. Figure 4-28 was created from the data in Table 6 and Table 15. Data in Figure 428 show the percent external t op shell gamma dose absorbed inte rnally in the clam shells as compared to the mean thickness of the top shell of the clams. For mean thickness of the top shell the range is 0.26 cm to 0.33 cm, the median is 0.29 cm and mean is 0.29 cm. The percent external top shell dose absorbed in ternally range is 61% to 112%, the median is 95% and the mean is 93%. The shell thickness does not appear to affect the dose received in Figure 4-28. Data in Figure 4-28 are more uniform than the da ta for electron beam (Figure 4-18) and the data for x-ray (Figure 4-23). Linear regression of the data shows a negative relationship between percentage of external dose absorbed internally and the mean top shell thickness at a 95% confidence interval. However, the fit of the line is not good with a R2 value of 0.0485. Multiple linear regression of this data shows no statistically significant relationship (P 0.05) between percentage of external dose absorbed internally and the mean top shell thickness. Thickness does not have a statistically significant effect on percentage of external dose absorbed in ternally for electron beam, x-ray or gamma.

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55 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 00.050.10.150.20.250.30.350.40.450.5Mean Top Shell Thickness (cm)Internal/External Dose (%) Figure 4-28. Percent external top shell dose absorbed internally in the clam shells as compared to the mean thickness of the top shell of the clams irradiated at doses of 1 kGy and 3 kGy with gamma at Food Technology Inc. (7/6/05). Solid line shows linear regression of data with =0.05 (y = -0.9988x + 1.2254 R2 = 0.0485). Figure 4-29 was created from the data in Table 5 and Table 15. Data in Figure 429 show the percent external t op shell gamma dose absorbed inte rnally in the clam shells as compared to the curvature of the top shell of the clams. For curvature of the top shell the range is 0.26 to 0.39, the median is 0.33 a nd mean is 0.33. The percent external top shell dose absorbed internally for gamma irradi ation range is 61% to 112%, the median is 95% and the mean is 93%. The data for the gamma (Figure 4-29) is more uniform than the data for electron beam (Figure 4-19) and x-ray (Figure 4-24). A very small negative relationship is exhibited with linear regression of the data at a 95% confidence interval. With a R2 value of 0.0003 the regression line does not fit the data very well however. In addition, multiple linear regression models of the data show no statistically significant relationship (P 0.05) between the percentage of extern al dose absorbed internally and the

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56 top shell curvature. Curvature is also not a factor in determining the percentage of external dose absorbed internally for electron beam, x-ray or gamma. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 00.10.20.30.40.50.60.70.80.91Top Shell CurvatureInternal/External Dose (%) Figure 4-29. Percent external top shell dose absorbed internally in the clam shells as compared to the curvature of the top she ll of the clams irradi ated at doses of 1kGy and 3 kGy with gamma at Food T echnology Inc. (7/6 /05). Solid line shows linear regression of data with =0.05 (y = -0.0652x + 0.9547 R2 = 0.0003). Figure 4-30 was created from the data in Table 4 and Table 15. Data in Figure 430 show the percent external t op shell dose absorbed internally in the clam shells as compared to the weight of the top shell of the clams. For weight of the top shell the range is 10.0g to 20.6g, the median is 13.0g and mean is 13.9g. The percent external top shell dose absorbed internally range is 70% to 117%, the median is 98% and the mean is 96%. Linear regression shows a ne gative relationship between percentages of external dose absorbed internally and t op shell weight at a 95% confidence interval. The line does not have a good fit however the R2 value is only 0.0485. No statistically significant relationship (P<0.05) exists between external dose absorbed intern ally and top shell

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57 weight in multiple linear regression models. Weight does not have a statistically significant relationship to percen tage of external dose absorbed internally for any of the three irradiation sources 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 0123456789101112131415161718192021Top Shell Weight (g)Internal/External Dose (%) Figure 4-30. Percent external top shell dose absorbed internally in the clam shells as compared to the weight of the top shell of the clam irradiated at doses of 1kGy and 3 kGy with gamma Food Technology Inc. (7/6/05). Solid line shows linear regression of data with =0.05 (y = -0.9988x + 1.2254 R2 = 0.0485). Clams irradiated with electron beam, x-ray or gamma have statistically significantly different (P<0.05) external doses an d internal doses. Percentage of external dose absorbed internally is not affected by top shell thickness, curv ature or weight in clams irradiated with electron beam, x-ray of gamma. Data for gamma is more tightly grouped than the data for electron beam or x-ray. Gamma also does not exhibit the concentration effect that electron beam and x -ray exhibit. For these reasons gamma is the most promising for irradiating clams industrially. Future experiments on irradiation of clams ar e needed to assess the effectiveness of irradiating clams on a large industrial scale. Experiments examining clams with a larger

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58 range of thicknesses, curvatures and weights could also be pe rformed in order to further validate the results of this research. Thes e experiments would increase the knowledge of irradiation of shellfish. Mussel Irradiation with Electron Beam Electron beam was also used to irradiate mussels. Mussels were purchased on May 12, 2005, irradiated with electron beam at NCEBFR on June 8, 2005. The mussels were shucked, measured and loaded with dosimeter st rips before irradiati on. After irradiation the dosimeter strips placed on the top mussel shell, bottom mussel shell and in between the mussel shells were read using spectrophotometery. 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 11.522.533.544.555.56 External Dose (kGy)Internal Dose (kGy) Figure 4-31. The internal absorbed dose shucked mussel shells as compared to the external absorbed dose of the top she ll of shucked mussels after exposure to electron beam at 1 kGy at NCEBFR (6/8/05). Solid line shows linear regression of data with =0.05 (y = -0.0271x + 1.6089 R2 = 0.0007). Figure 4-31 was created from the data in Table 16. Data in Figure 4-31 show the internal absorbed dose compared to the exte rnal top absorbed dose of the mussel shells irradiated at a dose of 1 kGy, as determin ed by the staff of NCEBFR. The doses

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59 absorbed inside the mussel shells range fr om 1.2 kGy to 2.1 kGy, have a median of 1.5 kGy and have a mean of 1.57 kGy. External top absorbed doses range from 1.3 kGy to 2.3 kGy, have a median of 1.6 kGy and have a mean of 1.63 kGy. The data for mussels irradiated with electr on beam is more tightly grouped than the data for clams and oysters irradiated with el ectron beam. The internal doses and external doses for mussels irradiated at 1 kGy with el ectron beam are not statistically significantly different (P 0.05). Even though the means for extern al dose and internal dose are not significantly different the data is far from ideal and not as tightly grouped as we would like. In eleven of the forty seven mussels ir radiated at 1 kGy the internal absorbed dose is higher than the external top absorbed dose. The concentration phenomenon is also exhibited in mussels as well as clams and mu ssels. External top dose mean is only 0.06 kGy larger than the internal absorbed dose m ean. Linear regression of the data shows a small negative relationship between the extern al and internal doses at a 95% confidence interval. However, the regression line is not a good fit for the data with a R2 value equal to 0.0007. Figure 4-32 was created from the data in Table 16. Data in Figure 4-32 show the internal absorbed dose compared to the exte rnal top absorbed dose of the mussel shells irradiated at a dose of 3 kGy, as determined by the staff of NCEBFR. The internal doses absorbed by the strips range from 1.3 kG y to 4.1 kGy, have a median of 3.1 kGy and have a mean of 3.00 kGy. External top ab sorbed doses range from 1.7 kGy to 4.2 kGy, have a median of 3.2 kGy and have a mean of 3.20 kGy.

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60 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 11.522.533.544.555.56External Dose (Kgy)Internal Dose (Kgy) Figure 4-32. The internal absorbed dose shucked mussel shells as compared to the external absorbed dose of the top shell of shucked mussels after exposure at 3 kGy at NCEBFR (6/8/05). Solid line shows linear regressi on of data with =0.05 (y = 0.5566x + 1.2022 R2 = 0.1406). The external dose and internal dose are statistically signi ficantly different (P<0.05). The mean dose absorbed internally is 3.00 which is the target dose. Even with this ideal mean there are thirteen of the fifty three mu ssels irradiated at 3 kGy with the internal absorbed dose is higher than the external t op absorbed dose. External top dose mean is 0.20 kGy larger than the internal absorbed dos e mean. Linear regression of the data shows a positive relationship between the external doses and internal doses at a confidence interval of 95%. The regression line is not a very good fit to the data with a R2 value of 0.1406. Even though the mean is exac tly the dose we wanted the data is not grouped as tightly as we would like to see. The concentration phenomenon also affects 24% of the mussels irradiated with 3 kGy.

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61 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 00.050.10.150.20.250.30.350.40.450.50.550.60.650.70.75Mean Top Shell Thickness (cm)Internal/External Dose (%) Figure 4-33. Percent external top shell dose absorbed internally in the mussel shells as compared to the mean thickness of the top shell of the mussels irradiated with electron beam at doses of 1kGy and 3 kGy NCEBFR (6/8/05). Solid line shows linear regression of data with =0.05 (y = -0.2862x + 1.0008 R2 = 0.0179). Figure 4-33 was created from the data in Table 9 and Table 16. Data in Figure 433 show the percent external t op shell dose absorbed internally in the mussel shells as compared to the mean thickness of the top sh ell of the mussels. For mean thickness of the top shell the range is 0.1cm to 0.62 cm, th e median is 0.13 cm and mean is 0.15 cm. The percent external top shell dose absorbed in ternally range is 41% to 150%, the median is 94% and the mean is 96%. The thicknesses of the top shells of the musse ls are very similar. The percentage of external dose absorbed internally covers a la rge rang and is not very uniform. Linear regression of the data shows a negative rela tionship between the perc entage of external dose absorbed internally and mean top she ll thickness at a 95% confidence interval. However, the linear regression line is not a good fit with a R2 value of 0.0179. A statistically signifi cant relationship (P 0.05) is not shown between percentage of external

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62 dose absorbed internally and mean top sh ell thickness in multiple linear regression models. Percent of external dose absorbed internally is not statistically significantly affected by top shell thickness for mussels irradi ated with electron beam. It was expected that thickness would have a strong negative re lationship to percentage of external dose absorbed internally, as with oysters and clams. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 00.10.20.30.40.50.60.70.80.91 Top Shell CurvatureInternal/External Dose (%) Figure 4-34. Percent external top shell dose absorbed internally in the mussel shells as compared to the curvature of the top she ll of the mussels irra diated at doses of 1kGy and 3 kGy NCEBFR (6/8/05). Solid line shows linear regression of data with =0.05 (y = -0.6613x + 1.0962 R2 = 0.0248). Figure 4-34 was created from the data in Table 8 and Table 16. Data in Figure 434 show the percent external t op shell dose absorbed internally in the mussel shells as compared to the curvature of the top shell of the mussels. For curvature of the top shell the range is 0.14 to 0.34, the median is 0.20 a nd mean is 0.21. The percent external top shell dose absorbed internally range is 41% to 150%, the medi an is 94% and the mean is 96%.

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63 The curvatures of the mussels (Figure 4-34) are more uniform than the curvatures of the oysters (Figure 4-4), but are less uniform than the curvatures of the clams (Figure 4-19). A negative relationship is shown betw een percentage of ex ternal dose absorbed internally and top shell curvature in lin ear regression models performed at a 95% confidence interval. The fit of the line is not good with a R2 value of 0.0248 however. Multiple linear regression models do not s how a statistically significant relationship (P 0.05) between percentage of external dose abso rbed internally and top shell curvature. Figure 4-35 was created from the data in Table 7 and Table 16. Data in Figure 435 show the percent external t op shell dose absorbed internally in the clam shells as compared to the weight of the top shell of the clams. For weight of the top shell the range is 2.0g to 6.8g, the median is 3.1g and mean is 3.2g. The percent external top shell dose absorbed internally range is 41% to 150%, the median is 94% and the mean is 95%. Linear regression shows a small negativ e relationship betwee n percentages of external dose absorbed internally and top shel l weight at a 95% conf idence interval. The line does not have a good fit however the R2 value is only 0.0013. No statistically significant relationship (P 0.05) exists between external dos e absorbed internally and top shell weight in multiple linear regression models. The data for mussels irradiated with electr on beam are very similar to the data for oysters and clams irradiated w ith electron beam. All of the external doses and internal doses of shellfish irradiated with electron beam are statistically significantly different (P<0.05) except the mussels irradiated with el ectron beam at 1 kGy. Even with similar means the data is not as tightly grouped as the data for gamma or x-ray. Electron beam

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64 also exhibits the concentration phenomenon in a ll three species of she llfish investigated. Top shell thickness, curvature and weight do not statistically significantly affect the percentage of external dose absorbed intern ally in oysters, clams or mussels irradiated with electron beam. Electron beam does not provide the uniformity of dose that we would like for any of the th ree shellfish investigated. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 012345678Top Shell Wt (g)Internal/Top Dose Figure 4-35. Percent external top shell dose absorbed internally in the mussel shells as compared to the weight of the top she ll of the mussel irradiated at doses of 1kGy and 3 kGy with electron beam NC EBFR (6/8/05). Solid line shows linear regression of data with =0.05 (y = -0.0074x + 0.9827 R2 = 0.0013). There are numerous future experiments that may help us better understand how to effectively use electron beam irradiation with shellfish. Irradiating shellfish on the half shell may be a viable option for irradiati ng with electron beam. The concentration phenomenon that is seen in electron beam also needs to be further investigated. Experiments with different dosimetery methods such as alanine dosimeters, may provide a better understanding of this phenomenon. Future experiments may help to provide better understanding and uses for electron beam.

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65 Mussel Irradiation with X-ray The second set of experiments for this research was performed with x-ray irradiation of shucked mussels. Mussel s were purchased on May 12, 2005, irradiated with x-ray at NCEBFR on June 26, 2005. The mussels were shucked, measured, irradiated with electron beam and loaded with dosimeter strips during the period inbetween. After irradiation with x-ray the dosimeter strips placed on the top mussel shell, bottom mussel shell and in between the mussel shells were read using spectrophotometery. 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 11.522.533.544.555.56 External Dose (kGy)Internal Dose (kGy) Figure 4-36. The internal absorbed dose shucked mussel shells as compared to the external absorbed dose of the top shell of shucked mussels after exposure to xray at 1 kGy at NCEBFR (6/26/05). So lid line shows linear regression of data with =0.05 (y = 0.0799x + 1.6661 R2 = 0.004). Figure 4-36 was created from the data in Table 17. Data in Figure 4-36 show the internal absorbed dose compared to the exte rnal top absorbed dose of the mussel shells irradiated by x-ray at a dose of 1 kGy, as determined by the staff of NCEBFR. The internal doses absorbed by th e strips range from 1.5 kGy to 2.2 kGy, have a median of

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66 1.8 kGy and have a mean of 1.81 kGy. Extern al top absorbed doses range from 1.6 kGy to 2.1 kGy, have a median of 1.8 kGy and have a mean of 1.81 kGy. The mean dose absorbed was larger than the 1kGy dose given as determined by NCEBFR for both external and internal dosimeters. Both doses at 1 kGy and 3 kGy are the same. The data in Figure 4-36 are much more uniform than the data for electron beam. The external doses and internal doses of mu ssels irradiated at 1 kGy with x-ray are not statistically significantly different (P 0.05). As with mussels irradiated with electron beam at 1 kGy the mean may be similar, but the data is not as tightly grouped as with gamma. Fifteen of the forty seven musse ls irradiated with x-ray at 1 kGy have an internal absorbed dose that is higher than the external top absorbed dose. Linear regression of the data at a 95% confidence interval shows a small positive relationship between external dose and internal dose. With a R2 value of 0.004 the regression line is not a good fit for the data however. Figure 4-37 was created from the data in Table 17. Data in Figure 4-37 show the internal absorbed dose compared to the exte rnal top absorbed dose of the mussel shells irradiated by x-ray at a dose of 3 kGy, as determined by the staff of NCEBFR. The internal doses absorbed by th e strips range from 1.8 kGy to 5.0 kGy, have a median of 4.4 kGy and have a mean of 4.29 kGy. Extern al top absorbed doses range from 1.6 kGy to 5.2 kGy, have a median of 4.4 kGy and have a mean of 4.29 kGy. The means of the internal doses and the external doses are equal. However, in nineteen of the fifty three mussels irradiated at 3 kGy the internal absorbed dose is higher than the external top absorbed dose. The concentration phenomenon is also seen in mussels irradiated with x-ray. External dos es and internal doses are not statistically

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67 significantly different (P 0.05). A positive relationship between external dose and internal dose is shown by linea r regression of the data at a 95% confidence interval. The regression line is a good fit to the data with a R2 value of 0.8522. The data for mussels irradiated with x-ray are more tightly grouped than the data fo r oysters or clams irradiated with x-ray. Even though mu ssels irradiated with x-ra y have means that are not statistically signifi cantly different (P 0.05) the data is not as tightly grouped as the data for mussels irradiated with gamma. 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 11.522.533.544.555.56External Dose (Kgy)Internal Dose (Kgy) Figure 4-37. The internal absorbed dose of shucked mussel shells as compared to the external absorbed dose of the top shell of shucked mussels after exposure to xray at 3 kGy at NCEBFR (6/26/05). So lid line shows linear regression of data with =0.05 (y = 0.842x + 0.6817 R2 = 0.8522). Figure 4-38 was created from the data in Table 9 and Table 17. Data in Figure 438 show the percent external t op shell x-ray dose absorbed in ternally in the mussel shells as compared to the mean thickness of the top sh ell of the mussels. For mean thickness of the top shell the range is 0.1 cm to 0.62 cm, the median is 0.13 cm and mean is 0.15 cm.

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68 The percent external top shell dose absorbed in ternally range is 79% to 122%, the median is 100% and the mean is 100%. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 00.050.10.150.20.250.30.350.40.450.50.550.60.650.70.75Mean Top Shell Thickness (cm)Internal/External Dose (%) Figure 4-38. Percent external top shell dose absorbed internally in the mussel shells as compared to the mean thickness of the top shell of the mussels irradiated at doses of 1kGy and 3 kGy with x-ray NC EBFR (6/26/05). Solid line shows linear regression of data with =0.05 (y = 0.2194x + 0.9718 R2 = 0.0408). The mussel top shell thicknesses examined in this research did not cover a large range. Linear regression of the data shows a positive relationship between the percentage of external doses absorbed internally and the mean top shell thickness at a confidence interval of 95%. Yet, th e regression line does not fit th e data very well with a R2 value of 0.0408. Multiple linear regressions of the data do not show a statis tically significant relationship (P 0.05) between percentage of external doses absorbed in ternally and the mean top shell thickness. Top shell thickne ss does not have a st atistically significant effect on the percentage of external dose abso rbed internally for oysters, clams or mussels irradiated with x-ray.

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69 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 00.10.20.30.40.50.60.70.80.91 Top Shell CurvatureInternal/External Dose (%) Figure 4-39. Percent external top shell dose absorbed internally in the mussel shells as compared to the curvature of the top she ll of the mussels irra diated at doses of 1kGy and 3 kGy with x-ray at NCEBFR (6/26/05). Solid line shows linear regression of data with =0.05 (y = 0.0654x + 0.9904 R2 = 0.0009). Figure 4-39 was created from the data in Table 8 and Table 17. Data in Figure 439 show the percent external t op shell x-ray dose absorbed in ternally in the mussel shells compared to the curvature of the top shell of the mussels. For curvature of the top shell the range is 0.14 to 0.39, the median is 0.20 a nd mean is 0.21. The percent external top shell dose absorbed internally range is 79% to 122%, the medi an is 100% and the mean is 100%. The data for curvature are relatively unifo rm covering a small range except for one offset data point. Although, the regr ession line is not a good fit with a R2 value of 0.0009 a positive relationship between percentage of external dose absorbed internally and top shell curvature is seen in linear regression m odels at a 95% confidence interval. Multiple linear regression of the data shows no statistically significant relationship (P 0.05) between the percentage of external dose ab sorbed internally and top shell curvature.

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70 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 012345678910 Top Shell Wt (g)Internal/Top Dose Figure 4-40. Percent external top shell dose absorbed internally in the mussel shells as compared to the weight of the top she ll of the mussel irradiated at doses of 1kGy and 3 kGy with x-ray NCEBFR (6 /26/05). Solid line shows linear regression of data with =0.05 (y = 0.0033x + 0.9933 R2 = 0.001). Figure 4-40 was created from the data in Table 7 and Table 17. Data in Figure 440 show the percent external t op shell dose absorbed internally in the clam shells as compared to the weight of the top shell of the clams. For weight of the top shell the range is 2.0g to 6.8g, the median is 3.1g and me an is 3.2g. The percen t external top shell dose absorbed internally range is 79% to 122%, the median is 100% and the mean is 100%. Linear regression shows a small negativ e relationship betwee n percentages of external dose absorbed internally and top shel l weight at a 95% conf idence interval. The line does not have a good fit however the R2 value is only 0.001. No statistically significant relationship (P 0.05) exists between external dos e absorbed internally and top shell weight in multiple linear regression models.

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71 Unlike oysters and clams, mussels irradi ated with x-ray are not statistically significantly different (P 0.05). The data for mussels irra diated with x-ray are more tightly grouped than the data for oysters or clams irradiated with x-ray. Top shell thickness, curvature and weight are also not statistically significantly affecting the percentage of external dose absorbed internal ly for any of the three species of shellfish irradiated with x-ray. Although x-ray does exhibit the concentra tion phenomenon in all of the shellfish investigated, x-ray may be a viable option for irradi ating mussels. Future experiments are needed to further expand the knowledge on irradiation of mussels. Experiments with different dosimetry met hods may provide a better understanding of the concentration effect seen in the shellfish irradiated with x-ray. Mussel Irradiation with Gamma A gamma source was also used to irradiat e the oysters. Mussels were purchased on May 12, 2005, irradiated with gamma at F ood Technology Inc. on July 6, 2005. The mussels were shucked, measured, irradiated wi th electron beam, irradiated with x-ray and loaded with dosimeter strips before irradi ation with gamma. After irradiation with gamma the dosimeter strips placed on the t op mussel shell, bottom mussel shell and in between the mussel shells were read using spectrophotometery. Figure 4-41 was created from the data in Table 18. Data in Figure 4-41 show the internal absorbed dose compared to the exte rnal top absorbed dose of the mussel shells irradiated by gamma at a dose of 1 kGy, as determined by the staff of Food Technology Inc. The internal doses range from 1.6 kGy to 2.0 kGy, have a median of 1.7 kGy and have a mean of 1.73 kGy. External top ab sorbed doses range from 1.6 kGy to 2.2 kGy, have a median of 1.9 kGy and have a mean of 1.89 kGy.

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72 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 11.522.533.544.555.56 External Dose (kGy)Internal Dose (kGy) Figure 4-41. The internal absorbed dose shucked mussel shells as compared to the external absorbed dose of the top she ll of shucked mussels after exposure to gamma at 1 kGy at Food Technology Inc. (7/6/05). Solid line shows linear regression of data with =0.05 (y = 0.4832x + 0.813 R2 = 0.3341). The mean dose absorbed was larger than the 1kGy dose given as determined by Food Technology Inc. for both external and in ternal dosimeters. External doses and internal doses are sta tistically significantly different (P <0.05) for mussels irradiated at 1 kGy with gammas. None of the forty seven mu ssels irradiated with gamma at 1 kGy have an internal absorbed dose higher than the ex ternal top absorbed dose. The gammas do not appear to have the concentration effect w ith in the shell that the electron beam and xrays have. External top dose mean is 0.16 kG y larger than the internal absorbed dose mean. Linear regression of the data shows a positive relationship between external dose and internal dose with a R2 value of 0.3341 at a confidence interval of 95%. Figure 4-42 was created from the data in Table 18. Data in Figure 4-42 show the internal absorbed dose compared to the exte rnal top absorbed dose of the mussel shells irradiated by gamma at a dose of 3 kGy, as determined by the staff of Food Technology

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73 Inc. The internal doses absorbed range fr om 1.6 kGy to 5.0 kGy, have a median of 4.4 kGy and have a mean of 4.23 kGy. External top absorbed doses range from 1.8 kGy to 5.0 kGy, have a median of 4.5 kGy and have a mean of 4.36 kGy. 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 11.522.533.544.555.56 External Dose (Kgy)Internal Dose (Kgy) Figure 4-42. The internal absorbed dose of shucked mussel shells as compared to the external absorbed dose of the top she ll of shucked mussels after exposure to gamma at 3 kGy at Food Technology Inc. (7/6/05). Solid line shows linear regression of data with =0.05 (y = 0.9897x 0.0884 R2 = 0.9634). The data for mussels irradiated with gamma are tightly fit along a straight line and clearly show the linear relation between intern al dose and external dose. Zero of the mussels irradiated with gamma at 3 kGy have an internal absorbed dose that is higher than the external top absorbed dose. Extern al top dose mean is 0.13 kGy larger than the internal absorbed dose mean. Mussels irradiated at 3 kGy with gammas have statistically significantly differe nt (P<0.05) external doses and internal doses. Linear regression of the data shows a positive rela tionship between the external and internal doses at a 95% confidence interval. The regr ession line is almost a perfect fit for this

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74 data with a R2 value of 0.9634. Gamma shows the ti ghtly grouped relationship that we want when irradiating shellfish. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 00.050.10.150.20.250.30.350.40.450.50.550.60.650.70.75Mean Top Shell Thickness (cm)Internal/External Dose (%) Figure 4-43. Percent external top shell dose absorbed internally in the mussel shells as compared to the mean thickness of the top shell of the mussels irradiated at doses of 1 kGy and 3 kGy with gamma at Food Technology Inc. (7/6/05). Solid line shows linear regression of data with =0.05 (y = -0.0671x + 0.953 R2 = 0.0108). Figure 4-43 was created from the data in Table 9 and Table 18. Data in Figure 443 show the percent external top shell gamm a dose absorbed internally in the mussel shells as compared to the mean thickness of the top shell of the mussels. For mean thickness of the top shell the range is 0.1 cm to 0.62 cm, the median is 0.13 cm and mean is 0.15 cm. The percent extern al top shell dose absorbed in ternally range is 80% to 100%, the median is 95% and the mean is 94%. The shell thickness does not appear to affect the dose received in Figure 4-43. Data in Figure 4-43 are more uniform than the da ta for electron beam (Figure 4-33) and the data for x-ray (Figure 4-38). Linear regr ession of the data sh ows a small negative relationship between percentage of external dose absorbed internally and the mean top

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75 shell thickness at a 95% confidence interval. However, the regressi on line is not a good fit for the data with a R2 value of 0.0108. Multiple linear regression models do not shows a statistically significant relationship (P 0.05) between percentage of external dose absorbed internally and the mean top shell thickness. None of the three species of shellfish examined in this research show a statistically significant relationship (P 0.05) between top shell thickness and the percenta ge of external dose absorbed internally. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 00.10.20.30.40.50.60.70.80.91 Top Shell CurvatureInternal/External Dose (%) Figure 4-44. Percent external top shell dose absorbed internally in the mussel shells as compared to the curvature of the top she ll of the mussels irra diated at doses of 1kGy and 3 kGy with gamma at Food T echnology Inc. (7/6 /05). Solid line shows linear regression of data with =0.05 (y = 0.1562x + 0.9108 R2 = 0.0152). Figure 4-44 was created from the data in Table 8 and Table 18. Data in Figure 444 shows the percent external top shell gamm a dose absorbed internally in the mussel shells as compared to the curvature of the t op shell of the mussels. For curvature of the top shell the range is 0.11 to 0.88, the medi an is 0.23 and mean is 0.24. The percent external top shell dose absorbed internally for gamma irradiation range is 74% to 100%, the median is 95% and the mean is 93%.

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76 The data for the gamma (Figure 4-44) is more uniform than the data for electron beam (Figure 4-34) and x-ray (Figure 4-39). Linear regression of the data shows a positive relationship between the percentage of external dose absorbed internally and the top shell curvature at a 95% confidence level. No statistically significant relationship (P 0.05) is shown between the percentage of ex ternal dose absorbed internally and the top shell curvature in multiple linear regres sion models. Curvature does not affect the percentage of external dose absorbed internally for oysters, clams or mussels. Figure 4-45 was created from the data in Table 7 and Table 18. Data in Figure 445 show the percent external t op shell dose absorbed internally in the clam shells as compared to the weight of the top shell of the clams. For weight of the top shell the range is 2.0g to 6.8g, the median is 3.1g and me an is 3.2g. The percen t external top shell dose absorbed internally range is 74% to 100%, the median is 94% and the mean is 93%. Linear regression shows a small negative rela tionship between percen tages of external dose absorbed internally and t op shell weight at a 95% confidence interval. The line does not have a good fit however the R2 value is only 0.0118. No statistically significant relationship (P 0.05) exists between exte rnal dose absorbed inte rnally and top shell weight in multiple linear regression models. Top shell weight does not have a significant affect on the percentage of external dose abso rbed internally for any of the three shellfish examined. The external doses and internal doses are statistically significantly different for the oysters, clams and mussels irradiated with gamma. However, gamma also provided the most tightly grouped data of all of the three irradia tion sources tested. This is as to be expected due to the higher energy and th erefore the higher pe netration of gamma

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77 irradiation. Top shell thickness, curvatur e and weight do not have a statistically significant relationship (P 0.05) to percentage of external dose absorbed internally for any of the species of shellf ish investigated in this re search. Gamma is the most promising of the three types of irradiation studied for i rradiating oysters, clams, and mussels. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 012345678910 Top Shell Wt (g)Internal/Top Dose Figure 4-45. Percent external top shell dose absorbed internally in the mussel shells as compared to the weight of the top she ll of the mussel irradiated at doses of 1kGy and 3 kGy with gamma Food Tec hnology Inc. (7/6/05). Solid line shows linear regression of data with =0.05 (y = 0.0068x + 0.9214 R2 = 0.0118). Oysters have the least tightly grouped data of the three shellfish studied for electron beam, x-ray and gamma. Data for clams ar e not as tightly grouped as data for mussels irradiated with electron beam, x-ray and gamma. This data confirms what we expected. Mussel should have the most uni form irradiation results since they have the thinnest and most uniform shells of the shellfish inves tigated. Irradiation data for clams are less uniform than mussels due to their thicker a nd less uniform shells and oysters have the least uniform irradiation data since their shells are the thickest and least uniform.

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78 However, when the shell geometry and weight ar e investigated for the three shellfish it is determined that shell thickness, curvature and weight do not sta tistically significantly affect the percentage of external dose absorb ed internally in oysters, clams and mussels irradiated with electron beam, x-ray and gamma. It was expected that thickness, curvature and weight would all have an effect on percentage of external dose absorbed internally in oysters, clams and mussels. One reason for this may be another more important factor overshadowing the effects thickness, curvature and weight. Another reason for this unexpected result may be the technique used to measure the shells. The shells were all measured on a macroscopic sc ale, yet the diverse landscape of the shell may yield better results if the shell is examin ed microscopically. These are all possible explanations for the unexpected results in these experiments. Gamma is the most promising of the three sources of irradiation studied. The most tightly grouped data is pr ovided by gamma for oysters, clams and mussels. X-ray provides tighter grouped data th an electron beam does. This is as expected. The energy and penetration of gammas are the highest, x-rays have the next highest energy and penetration and electron beam have the lowest energy and penetration. X-ray and electron beam exhibit the concentration phe nomenon where the intern al dose is higher than the applied external dose. It is for thes e reasons and others that gamma irradiation is the most viable source for irradiating shellfish on a large industrial scale. This research creates questi ons that should be answered by future research. First, different dosimeters could be used to help clar ify the data presented in this research. The use of different dosimetry may also help to clarify the concentration phenomenon that is seen with electron beam and x-ray. Also fu ture experiments should be performed with

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79 microscopic measuring techniques to examin e thickness and curvature. As mentioned above experiments with shellfish on the half shell may be promising for electron beam and x-ray since the shell is not present as a ba rrier. Large scale e xperiments, using tons of shellfish, with gamma i rradiation should also be pe rformed to determine the penetration of dose in pallets of shellfish. Economic expe riments to compare electron beam, x-ray and gamma may also provide valu able information about the practicality of large scale irradiation of shellfish. With the help of experiments such as these irradiation of shellfish may become vi able industrial practice.

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80 CHAPTER 5 SUMMARY AND CONCLUSIONS The primary objective of this research was to compare and contrast the percentage of absorption of irradiation in oyster, clam and mussel she lls using gamma, electron beam and x-ray irradiation sources at dosages of 1 kGy and 3 kGy. Oyster, clam and mussel shells were assessed for differences in extern al absorbed dose and internal absorbed dose for electron beam, x-ray and gamma sources. Furthermore, the thickness, weight and curvatures for oyster, clam and mussel shells were assessed with respect to the effect on percentage of applied do se absorbed internally. When clam and oyster shells were irradi ated using gamma, x-ray or electron beam at 1 kGy and 3 kGy, the absorbed internal dose was less than the external dose and was determined to be significantly different (P< 0.05) when compared to the external absorbed shell dose. When mussel shells were irradiat ed using electron beam at 1 kGy or x-ray at 1 kGy and 3 kGy no statistical significant differences (P 0.05) were determined to exist between the external and internal absorbed dose. However, when mussel shells were irradiated with electron beam at 3 kGy and gamma irradiation at 1 kGy and 3 kGy, significant differences (P<0.05) were determ ined to exist between the external and internal absorbed doses. When oyster, clam and mussel shells were irradiated with electron beam and x-ray a concentration phe nomenon, where internal doses were greater than the external doses, was exhibited. Sp ecifically, the concentr ation phenomenon was exhibited in 12% of the oyste r shells, 12% of the clam sh ells and 24% of the mussel shells irradiated with elec tron beam. The concentrati on phenomenon was exhibited in

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81 14% of the oyster shells, 17% of the clam shells and 34% of the mussel shells irradiated with x-ray. When top shell thickness, weight and curvat ure for oyster, clam and mussel shells were statistically compared to the percentage ratio of external/internal absorbed dose, no significant relationship (P 0.05) was revealed. Specificall y, no statistical relationship was demonstrated between the percentage exte rnal dose absorbed in ternally and the top shell thickness, curvature of the shell and we ight of the shell usi ng electron beam, x-ray and gamma at 1 kGy and 3 kGy. Therefore, oyster, clam and mussel shell thickness, shell curvature and shell wei ght did not have a statistical significant relationship or influence on the percentage of external/internal absorb ed dose at 1 kGy and 3 kGy. Reasons for the differences between external and internal absorbed doses and concentration phenomenon are unclear and can not be accounted for by differences in shell thickness, shell wei ght or shell curvature.

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82 APPENDIX A OYSTER, CLAM, AND MUSSEL MEASUREMENTS Oyster Measurements Table A-1. Oyster Weight M easurements in g (5/1/05) Oyster Overall wt Meat wt Shell wt Top Shell wt Bottom Shell wt Shell/ Meat Top/ Bottom Top/ Meat Bottom/ Meat 1 84.2 16.1 68.1 47.3 20.8 4.23 2.27 2.94 1.29 2 67.8 6.1 61.7 30.4 31.3 10.11 0.97 4.98 5.13 3 59.1 5.9 53.2 32.1 21.1 9.02 1.52 5.44 3.58 4 55.5 6.8 48.7 29.5 19.2 7.16 1.54 4.34 2.82 5 37.0 4.2 32.8 19.4 13.4 7.81 1.45 4.62 3.19 6 64.1 8.0 56.1 33.3 22.8 7.01 1.46 4.16 2.85 7 41.2 3.6 37.6 20.8 16.8 10.44 1.24 5.78 4.67 8 57.7 4.5 53.2 39.8 13.4 11.82 2.97 8.84 2.98 9 91.8 12.4 79.4 48.3 31.1 6.40 1.55 3.90 2.51 10 72.5 11.8 60.7 37.5 23.2 5.14 1.62 3.18 1.97 11 50.9 8.0 42.9 26.4 16.5 5.36 1.60 3.30 2.06 12 47.1 5.6 41.5 23 18.5 7.41 1.24 4.11 3.30 13 56.3 7.6 48.7 32.6 16.1 6.41 2.02 4.29 2.12 14 45.0 6.0 39.0 23.4 15.6 6.50 1.50 3.90 2.60 15 63.7 9.2 54.5 32.2 22.3 5.92 1.44 3.50 2.42 16 107.8 15.9 91.9 53.7 38.2 5.78 1.41 3.38 2.40 17 105.1 12.6 92.5 49.6 42.9 7.34 1.16 3.94 3.40 18 59.6 7.3 52.3 30.4 21.9 7.16 1.39 4.16 3.00 19 66.7 9.5 57.2 35.8 21.4 6.02 1.67 3.77 2.25 20 64.7 10.0 54.7 33.7 21.0 5.47 1.60 3.37 2.10 21 138.9 17.3 121.6 76.2 45.4 7.03 1.68 4.40 2.62 22 48.9 7.9 41.0 22.9 18.1 5.19 1.27 2.90 2.29 23 57.8 7.9 49.9 31.9 18.0 6.32 1.77 4.04 2.28 24 70.8 9.0 61.8 36.1 25.7 6.87 1.40 4.01 2.86 25 81.9 11.6 70.3 42.2 28.1 6.06 1.50 3.64 2.42 26 41.5 6.2 35.3 18.7 16.6 5.69 1.13 3.02 2.68 27 47.0 7.1 39.9 24.3 15.6 5.62 1.56 3.42 2.20 28 63.0 12.0 51.0 32.7 18.3 4.25 1.79 2.73 1.53 29 83.2 13.9 69.3 47.4 21.9 4.99 2.16 3.41 1.58 30 57.0 9.3 47.7 33.2 14.5 5.13 2.29 3.57 1.56 31 43.6 5.1 38.5 22.2 16.3 7.55 1.36 4.35 3.20 32 81.6 8.7 72.9 45.7 27.2 8.38 1.68 5.25 3.13 33 57.0 6.3 50.7 29.7 21.0 8.05 1.41 4.71 3.33 34 57.7 8.0 49.7 30.9 18.8 6.21 1.64 3.86 2.35 35 58.5 8.4 50.1 32.8 17.3 5.96 1.90 3.90 2.06 36 86.9 11.1 75.8 44.5 31.3 6.83 1.42 4.01 2.82 37 44.5 4.0 40.5 28 12.5 10.13 2.24 7.00 3.13 38 56.1 8.3 47.8 33.5 14.3 5.76 2.34 4.04 1.72 39 59.4 10.2 49.2 29.9 19.3 4.82 1.55 2.93 1.89 40 45.5 9.1 36.4 24.3 12.1 4.00 2.01 2.67 1.33

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83 Table A-1. Continued Oyster Overall wt Meat wt Shell wt Top Shell wt Bottom Shell wt Shell/ Meat Top/ Bottom Top/ Meat Bottom/ Meat 41 41.0 6.8 34.2 21.5 12.7 5.03 1.69 3.16 1.87 42 45.4 7.1 38.3 20.1 18.2 5.39 1.10 2.83 2.56 43 54.0 8.8 45.2 26.8 18.4 5.14 1.46 3.05 2.09 44 62.5 6.6 55.9 35.5 20.4 8.47 1.74 5.38 3.09 45 55.6 10.8 44.8 27.8 17.0 4.15 1.64 2.57 1.57 46 39.1 7.0 32.1 19.3 12.8 4.59 1.51 2.76 1.83 47 65.0 14.9 50.1 32.3 17.8 3.36 1.81 2.17 1.19 48 57.0 15.5 41.5 25.9 15.6 2.68 1.66 1.67 1.01 49 83.8 9.2 74.6 48.0 26.6 8.11 1.80 5.22 2.89 50 53.5 11.0 42.5 29.0 13.5 3.86 2.15 2.64 1.23 51 69.2 8.6 60.6 39.1 21.5 7.05 1.82 4.55 2.50 52 54.3 10.7 43.6 27.8 15.8 4.07 1.76 2.60 1.48 53 37.3 5.7 31.6 20.7 10.9 5.54 1.90 3.63 1.91 54 48.9 6.9 42.0 30.0 12.0 6.09 2.50 4.35 1.74 55 48.8 6.2 42.6 24.7 17.9 6.87 1.38 3.98 2.89 56 34.2 5.9 28.3 17.3 11.0 4.80 1.57 2.93 1.86 57 42.2 6.0 36.2 21.0 15.2 6.03 1.38 3.50 2.53 58 66.6 12.7 53.9 34.6 19.3 4.24 1.79 2.72 1.52 59 54.8 4.6 50.2 28.8 21.4 10.91 1.35 6.26 4.65 60 54.0 8.2 45.8 29.1 16.7 5.59 1.74 3.55 2.04 61 63.5 8.8 54.7 29.4 25.3 6.22 1.16 3.34 2.88 62 67.0 6.2 60.8 36.0 24.8 9.81 1.45 5.81 4.00 63 63.7 13.4 50.3 32.5 17.8 3.75 1.83 2.43 1.33 64 129.2 12.5 116.7 69.3 47.4 9.34 1.46 5.54 3.79 65 50.1 6.6 43.5 27.2 16.3 6.59 1.67 4.12 2.47 66 80.7 10.5 70.2 42.7 27.5 6.69 1.55 4.07 2.62 67 48.8 9.0 39.8 22.1 17.7 4.42 1.25 2.46 1.97 68 73.6 9.6 64.0 48.7 15.3 6.67 3.18 5.07 1.59 69 108.3 14.0 94.3 65.6 28.7 6.74 2.29 4.69 2.05 70 87.3 9.2 78.1 46.0 32.1 8.49 1.43 5.00 3.49 71 65.6 10.6 55.0 35.5 19.5 5.19 1.82 3.35 1.84 72 108.6 12.6 96.0 62.0 34.0 7.62 1.82 4.92 2.70 73 51.7 9.8 41.9 25.5 16.4 4.28 1.55 2.60 1.67 74 42.3 8.6 33.7 19.8 13.9 3.92 1.42 2.30 1.62 75 65.5 10.1 55.4 34.7 20.7 5.49 1.68 3.44 2.05 76 60.1 7.6 52.5 27.4 25.1 6.91 1.09 3.61 3.30 77 54.4 6.9 47.5 28.2 19.3 6.88 1.46 4.09 2.80 78 65.9 10.1 55.8 30.6 25.2 5.52 1.21 3.03 2.50 79 136.8 24.4 112.4 71.9 40.5 4.61 1.78 2.95 1.66 80 81.7 9.8 71.9 39.8 32.1 7.34 1.24 4.06 3.28 81 55.0 8.9 46.1 25.3 20.8 5.18 1.22 2.84 2.34 82 64.1 12.0 52.1 30.6 21.5 4.34 1.42 2.55 1.79 83 59.3 7.5 51.8 32.4 19.4 6.91 1.67 4.32 2.59 84 80.6 13.3 67.3 46.1 21.2 5.06 2.17 3.47 1.59 85 70.5 15.3 55.2 29.2 26.0 3.61 1.12 1.91 1.70 86 55.9 10.9 45.0 29.3 15.7 4.13 1.87 2.69 1.44 87 42.9 9.2 33.7 20.1 13.6 3.66 1.48 2.18 1.48 88 96.4 11.1 85.3 45.0 40.3 7.68 1.12 4.05 3.63 89 62.7 9.8 52.9 32.7 20.2 5.40 1.62 3.34 2.06 90 114.7 13.9 100.8 63.1 37.7 7.25 1.67 4.54 2.71

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84 Table A-1. Continued Oyster Overall wt Meat wt Shell wt Top Shell wt Bottom Shell wt Shell/ Meat Top/ Bottom Top/ Meat Bottom/ Meat 91 84.3 13.0 71.3 43.9 27.4 5.48 1.60 3.38 2.11 92 52.5 9.6 42.9 22.4 20.5 4.47 1.09 2.33 2.14 93 72.5 8.2 64.3 39.8 24.5 7.84 1.62 4.85 2.99 94 59.3 11.4 47.9 29.5 18.4 4.20 1.60 2.59 1.61 95 38.3 6.9 31.4 18.3 13.1 4.55 1.40 2.65 1.90 96 57.7 10.3 47.4 30.5 16.9 4.60 1.80 2.96 1.64 97 68.7 10.4 58.3 35.2 23.1 5.61 1.52 3.38 2.22 98 55.1 10.7 44.4 28.2 16.2 4.15 1.74 2.64 1.51 99 57.5 9.5 48.0 28.0 20.0 5.05 1.40 2.95 2.11 100 50.4 8.8 41.6 21.8 19.8 4.73 1.10 2.48 2.25 Table A-2. Oyster Dimension Me asurements in cm (5/3/05) Oyster Top Length Top Height Top Width Bottom Length Bottom Height Bottom Width Total Length Total Height Total Width 1 10.6 2.2 5.8 8.3 0.65 4.85 10.6 2.85 5.8 2 6.5 1.65 6.1 5.6 1.05 5.3 6.5 2.7 6.1 3 7.3 1.5 4.5 5.05 0.8 3.65 7.3 2.3 4.5 4 6.3 2.1 6.0 4.8 1.0 5.15 6.3 3.1 6.0 5 6.2 1.3 4.1 5.3 0.9 3.6 6.2 2.2 4.1 6 6.75 1.4 4.8 5.7 1.1 3.9 6.75 2.5 4.8 7 5.8 1.55 4.5 5.15 1.0 3.8 5.8 2.55 4.5 8 6.3 1.5 4.0 5.5 1.05 3.7 6.3 2.55 4.0 9 6.5 0.7 4.7 5.5 1.2 3.9 6.5 1.9 4.7 10 9.4 2.0 4.7 7.5 0.65 4.45 9.4 2.65 4.7 11 7.6 1.6 5.2 6.3 0.45 4.45 7.6 2.05 5.2 12 6.6 1.85 4.75 6.05 1.05 4.15 6.6 2.9 4.75 13 8.2 2.0 4.9 6.7 0.7 4.1 8.2 2.7 4.9 14 7.8 1.6 3.7 6.7 0.65 3.5 7.8 2.25 3.7 15 7.7 1.65 3.95 7.15 0.8 4.1 7.7 2.45 3.95 16 8.4 1.75 7.45 7.1 1.45 5.4 8.4 3.2 7.45 17 8.65 1.85 5.2 7.35 1.5 4.65 8.65 3.35 5.2 18 6.3 1.8 5.6 5.8 0.95 5.1 6.3 2.75 5.6 19 8.4 2.3 4.9 7.35 1.0 4.15 8.4 3.3 4.9 20 7.69 2.0 5.2 6.9 0.8 4.6 7.69 2.8 5.2 21 9.0 2.0 5.2 6.9 0.8 4.6 9.0 2.8 5.2 22 4.45 1.9 3.9 5.3 0.6 3.7 5.3 2.5 3.9 23 7.5 2.3 5.3 5.7 0.9 4.45 7.5 3.2 5.3 24 7.0 1.2 4.75 6.1 1.2 4.05 7.0 2.4 4.75 25 8.4 2.3 4.9 7.35 1.0 4.15 8.4 3.3 4.9 26 6.0 1.4 4.4 5.15 0.9 4.2 6.0 2.3 4.4 27 6.75 1.5 4.9 5.95 0.65 3.85 6.75 2.15 4.9 28 8.8 2.2 5.75 6.8 0.65 4.55 8.8 2.85 5.75 29 9.4 2.1 4.1 8.9 1.0 3.4 9.4 3.1 4.1 30 9.2 1.35 3.9 6.85 0.95 3.4 9.2 2.3 3.9 31 9.05 1.45 4.3 7.2 0.6 3.45 9.05 2.05 4.3 32 6.1 1.6 6.15 6.05 1.0 4.75 6.1 2.6 6.15 33 5.8 1.9 4.1 6.0 0.65 4.3 6.0 2.55 4.3 34 7.65 2.1 4.4 6.7 0.6 4.05 7.65 2.7 4.4 35 7.65 2.1 4.4 6.7 0.6 4.05 4.68 2.7 4.4 36 7.8 1.7 5.6 6.5 1.2 4.5 7.8 2.9 5.6

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85 Table A-2. Continued Oyster Top Length Top Height Top Width Bottom Length Bottom Height Bottom Width Total Length Total Height Total Width 37 8.3 2.5 4.75 6.2 0.9 3.8 8.3 3.4 4.75 38 7.7 1.9 3.7 6.4 0.6 3.1 7.7 2.5 3.7 39 9.3 1.45 4.8 8.3 0.6 4.15 9.3 2.05 4.8 40 8.8 1.7 4.2 7.15 0.6 3.55 8.8 2.3 4.2 41 7.5 1.7 3.7 6.85 0.3 3.15 7.5 2.0 3.7 42 6.8 1.5 5.1 5.15 1.0 4.1 6.8 2.5 5.1 43 6.95 1.7 5.1 5.75 1.0 4.0 6.95 2.7 5.1 44 8.3 1.75 2.9 6.3 0.7 2.8 8.3 2.45 2.9 45 6.4 2.4 4.5 5.15 0.95 3.55 6.4 3.35 4.5 46 6.9 1.5 4.0 6.2 0.55 3.4 6.9 2.05 4.0 47 8.79 1.9 5.65 7.4 0.5 4.3 8.79 2.4 5.65 48 7.9 1.95 5.5 5.5 0.7 4.1 7.9 2.65 5.5 49 6.15 1.4 5.5 5.95 1.1 4.0 6.15 2.5 5.5 50 8.9 1.6 4.4 7.5 0.5 3.4 8.9 2.1 4.4 51 8.9 2.2 5.6 7.5 .55 4.6 8.9 2.75 5.6 52 8.7 1.9 5.4 6.8 0.45 4.15 8.7 2.35 5.4 53 9.7 1.8 3.8 7.0 0.55 3.0 9.7 2.35 3.8 54 6.65 1.75 3.75 5.3 0.6 3.0 6.65 2.35 3.75 55 5.65 1.6 5.6 4.9 0.75 3.7 5.65 2.35 5.6 56 8.85 1.15 3.65 6.6 0.55 3.3 8.85 1.7 3.65 57 6.3 1.5 4.85 5.2 0.75 3.95 6.3 2.25 4.85 58 8.45 1.7 7.05 6.9 0.75 4.3 8.45 2.45 7.05 59 6.9 1.45 4.5 6.0 1.1 3.9 6.9 2.55 4.5 60 8.75 2.0 4.75 7.1 1.15 2.7 8.75 3.15 4.75 61 8.8 1.35 4.5 7.5 0.75 3.55 8.8 2.1 4.5 62 6.2 1.6 5.1 5.4 1.75 3.9 6.2 3.35 5.1 63 9.85 2.75 5.1 7.75 0.6 4.2 9.85 3.35 5.1 64 8.5 1.6 6.5 7.2 1.2 6.0 8.5 2.8 6.5 65 6.55 1.7 3.6 5.05 0.8 3.1 6.55 2.5 3.6 66 7.1 2.1 5.75 6.1 1.0 4.9 7.1 3.1 5.75 67 7.1 1.6 4.8 5.8 0.6 3.5 7.1 2.2 4.8 68 7.8 2.55 4.8 6.7 0.5 4.2 7.8 3.05 4.8 69 9.35 2.15 6.0 7.5 .85 4.75 9.35 3.0 6.0 70 9.3 1.45 5.3 6.7 70 4.4 9.3 71.45 5.3 71 9.5 1.8 4.4 6.85 0.6 4.0 9.5 2.4 4.4 72 8.85 1.5 5.75 8.25 0.8 4.9 8.85 2.3 5.75 73 9.15 1.3 3.9 7.65 0.5 3.5 9.15 1.8 3.9 74 6.8 1.7 4.6 7.2 0.55 3.7 7.2 2.25 4.6 75 8.85 1.45 4.6 5.65 0.45 3.7 8.85 1.9 4.6 76 6.3 1.45 4.45 5.85 0.9 4.1 6.3 2.35 4.45 77 6.6 1.6 5.15 5.6 0.9 3.7 6.6 2.5 5.15 78 8.75 1.55 4.9 7.4 0.9 3.6 8.75 2.45 4.9 79 8.6 2.6 5.6 7.7 1.8 4.8 8.6 4.4 5.6 80 7.6 1.9 5.2 6.55 1.45 4.4 7.6 3.35 5.2 81 6.9 1.6 5.0 5.8 1.15 4.1 6.9 2.75 5.0 82 8.65 1.9 5.0 7.0 1.7 4.9 8.65 3.6 5.0 83 7.3 2.4 4.45 5.75 0.7 3.9 7.3 3.1 4.45 84 8.8 1.85 4.55 6.5 0.9 4.2 8.8 2.75 4.55 85 10.5 1.6 5.35 10.2 0.5 4.3 10.5 2.1 5.35 86 7.1 1.6 4.4 5.4 0.85 4.0 7.1 2.45 4.4

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86 Table A-2. Continued Oyster Top Length Top Height Top Width Bottom Length Bottom Height Bottom Width Total Length Total Height Total Width 87 7.65 1.75 4.4 5.9 0.65 3.9 7.65 2.4 4.4 88 7.4 2.3 5.0 6.8 1.55 4.05 7.4 3.85 5.0 89 7.65 1.55 4.8 6.55 0.55 4.15 7.65 2.1 4.8 90 9.8 2.1 6.3 7.8 0.85 4.75 9.8 2.95 6.3 91 10.35 2.95 5.0 8.75 0.9 4.05 10.35 3.85 5.0 92 8.6 .95 4.7 6.85 0.55 4.3 8.6 1.5 4.7 93 7.95 7.0 6.0 6.3 0.8 4.95 7.95 7.8 6.0 94 8.1 1.9 4.3 6.9 0.5 3.8 8.1 2.4 4.3 95 7.4 1.5 3.5 5.8 0.5 3.25 7.4 2.0 3.5 96 6.9 2.1 4.4 5.6 0.9 4.1 6.9 3.0 4.4 97 9.0 1.9 5.05 6.9 1.0 4.6 9.0 2.9 5.05 98 8.3 2.1 4.3 6.45 0.6 3.85 8.3 2.7 4.3 99 7.9 2.0 4.35 6.6 0.55 3.8 7.9 2.55 4.35 100 5.7 1.75 4.3 5.35 1.75 4.0 5.7 3.5 4.3 Table A-3. Oyster Thickness Measurements in cm (5/4/05) Oyster 1Top 2Top 3Top 4Top 5Top 1Bottom 2Bottom 3Bottom 4Bottom 5Bottom 1 0.231 0.318 0.724 0.533 0.373 0.292 0.277 0.269 0.282 0.470 2 0.445 0.559 0.803 0.658 0.457 0.533 0.302 0.521 0.645 0.287 3 0.221 0.414 0.696 0.635 0.277 0.279 0.566 0.930 0.483 0.343 4 0.787 0.439 0.282 0.292 0.564 0.328 0.254 0.749 0.320 0.523 5 0.538 0.399 0.257 0.368 0.457 0.716 0.211 0.432 0.427 0.193 6 0.625 0.439 0.414 0.340 0.859 0.836 0.381 0.366 0.389 0.686 7 0.343 0.699 0.828 0.305 0.358 0.732 0.427 0.343 0.312 0.320 8 0.356 0.396 0.737 0.445 0.378 0.335 0.505 0.765 0.638 0.696 9 0.792 0.470 0.277 0.533 0.218 0.409 0.668 0.828 0.429 0.892 10 0.513 0.622 0.683 0.457 0.320 0.328 0.353 0.310 0.584 0.546 11 0.180 0.353 0.787 0.536 0.307 0.218 0.417 0.277 0.409 0.292 12 0.645 0.566 0.559 0.406 0.437 0.622 0.790 0.300 0.686 0.335 13 0.536 0.267 0.432 0.551 0.264 0.320 0.414 0.391 0.216 0.434 14 0.201 0.274 0.523 0.325 0.272 0.391 0.267 0.516 0.323 0.450 15 0.262 0.460 0.318 0.295 0.305 0.257 0.282 0.292 0.325 0.259 16 0.635 0.904 0.432 0.620 0.508 0.556 0.810 0.432 0.399 0.528 17 0.389 0.437 0.777 1.064 0.699 0.315 0.561 1.003 0.775 0.704 18 0.765 0.554 0.866 0.526 0.612 0.323 0.544 0.391 0.358 0.447 19 0.312 0.429 0.419 0.584 0.391 0.284 0.401 0.508 0.749 1.092 20 0.386 0.521 0.320 0.401 0.457 0.445 0.508 0.384 0.472 0.584 21 1.019 0.643 0.384 0.493 0.566 0.371 0.643 0.820 0.686 0.318 22 0.328 0.356 0.333 0.282 0.333 0.279 0.333 0.287 0.432 0.414 23 0.765 0.399 0.417 0.559 0.597 0.577 0.414 0.452 0.566 0.338 24 0.551 0.536 0.838 0.622 0.737 0.368 0.445 0.635 1.064 0.356 25 0.142 0.645 1.062 0.749 0.866 0.302 0.409 0.714 0.907 0.483 26 0.361 0.216 0.671 0.267 0.287 0.643 0.445 0.305 0.673 0.312 27 0.381 0.315 0.508 0.528 0.516 0.290 0.305 0.693 0.475 0.503 28 0.305 0.254 0.323 0.521 0.343 0.325 0.394 0.257 0.330 0.526 29 0.411 0.724 1.262 0.513 0.409 0.211 0.483 0.864 0.310 0.409 30 0.218 0.262 0.396 0.536 0.940 0.269 0.401 0.498 0.292 0.500 31 0.127 0.368 0.538 0.211 0.284 0.638 0.493 0.249 0.175 0.287 32 0.599 0.592 0.927 0.681 0.683 0.597 0.531 0.706 0.800 1.105 33 0.300 0.394 0.627 1.240 1.130 0.343 0.361 0.419 0.894 0.785

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87 Table A-3. Continued Oyster 1Top 2Top 3Top 4Top 5Top 1Bottom 2Bottom 3Bottom 4Bottom 5Bottom 34 0.295 0.556 0.851 0.787 0.673 0.742 0.439 0.419 0.267 0.478 35 0.409 1.143 0.345 0.373 0.251 0.292 0.356 0.541 0.295 0.445 36 0.267 0.544 0.498 1.173 0.902 0.467 0.470 0.719 1.016 0.295 37 0.277 1.067 0.399 0.699 0.678 0.208 0.419 0.648 0.335 0.226 38 0.333 0.340 0.112 0.635 0.358 0.318 0.320 0.437 0.757 0.419 39 0.358 0.523 0.434 0.432 0.229 0.439 0.231 0.414 0.246 0.300 40 0.234 0.295 1.087 0.328 0.297 0.305 0.404 0.297 0.274 0.224 41 0.279 0.406 0.229 1.085 0.236 0.216 0.318 0.340 0.348 0.483 42 0.498 0.401 0.556 0.300 0.295 0.353 0.419 0.279 0.754 0.551 43 0.267 0.325 0.544 0.282 0.500 0.300 0.442 0.833 0.366 0.467 44 0.597 0.389 0.508 0.803 0.917 0.401 0.653 0.429 0.335 0.599 45 0.610 0.244 0.638 1.250 0.607 0.617 0.846 0.785 0.241 0.297 46 0.368 0.259 0.295 0.345 0.320 0.310 0.333 0.203 0.419 0.295 47 0.279 0.391 0.345 0.318 0.488 0.264 0.353 0.312 0.284 0.325 48 0.142 0.378 0.437 0.643 0.518 0.287 0.353 0.432 0.432 0.531 49 0.584 0.381 0.864 0.584 0.749 0.813 0.478 0.323 0.343 0.531 50 0.399 0.231 0.330 0.439 0.414 0.152 0.254 0.262 0.315 0.338 51 0.191 0.338 0.521 1.148 0.422 0.226 0.269 0.452 0.414 0.351 52 0.173 0.264 0.447 0.655 0.470 0.185 0.579 0.394 0.617 0.234 53 0.437 0.500 0.348 0.432 0.282 0.234 0.325 0.546 0.523 0.226 54 0.541 0.381 0.439 0.226 0.429 0.394 0.295 0.394 0.622 0.404 55 0.218 0.561 0.960 0.818 0.622 0.277 0.513 0.523 0.724 0.734 56 0.356 0.320 0.178 0.312 0.343 0.160 0.142 0.191 0.300 0.356 57 0.312 0.762 0.264 0.439 0.335 0.330 0.572 0.295 0.615 0.554 58 0.320 0.262 0.292 0.348 0.503 0.457 0.432 0.241 0.445 0.409 59 0.513 1.026 0.328 0.340 0.599 0.325 0.391 0.549 0.759 0.218 60 0.371 0.330 0.244 0.368 0.665 0.216 0.320 0.318 0.203 0.244 61 0.310 0.368 0.493 0.455 0.208 0.361 0.396 0.284 0.051 0.622 62 0.264 0.531 0.861 1.161 0.490 0.292 0.437 0.937 0.630 0.445 63 0.198 0.269 0.632 0.622 0.615 0.170 0.521 0.307 0.338 0.480 64 0.356 0.279 0.904 1.087 0.820 0.284 0.338 0.810 1.090 0.747 65 0.170 0.495 0.843 1.011 0.493 0.206 0.399 0.455 0.625 0.483 66 0.307 0.368 1.143 1.400 0.478 0.259 0.488 0.879 0.521 0.345 67 0.305 0.556 0.295 0.320 0.363 0.417 0.386 0.218 0.267 0.389 68 0.307 0.315 0.208 0.566 1.057 0.226 0.239 0.206 0.442 0.495 69 0.173 0.554 0.785 0.564 0.605 0.282 0.335 0.523 0.663 0.594 70 0.257 0.361 0.279 0.432 0.699 0.231 0.274 0.356 0.358 0.325 71 1.478 0.041 0.030 0.025 0.284 0.297 0.465 0.330 0.546 0.279 72 0.226 0.409 0.742 1.430 0.785 0.297 0.508 0.508 0.673 0.513 73 0.414 0.259 0.274 0.277 0.254 0.203 0.323 0.295 0.719 0.267 74 0.500 0.323 0.488 0.851 0.559 0.246 0.437 0.302 0.323 0.378 75 0.249 0.356 0.488 0.726 0.813 0.267 0.384 0.292 0.470 0.584 76 0.597 0.368 0.528 0.960 0.526 0.483 0.559 0.523 0.785 0.640 77 0.137 0.592 0.881 0.419 0.838 0.300 0.439 0.762 0.467 0.262 78 0.422 0.406 0.330 0.343 0.318 0.417 0.284 0.343 0.399 0.493 79 0.091 0.732 1.173 2.428 0.401 0.244 0.594 1.171 1.356 0.295 80 0.638 0.655 0.262 0.683 0.772 1.151 0.765 0.495 0.381 0.409 81 0.264 0.665 0.262 0.333 0.775 0.605 0.343 0.429 0.516 0.406 82 0.267 0.325 0.508 0.351 0.267 0.267 0.437 0.251 0.394 0.470 83 0.587 0.445 0.241 0.549 0.635 0.323 0.465 0.602 0.640 0.617 84 0.183 0.368 0.635 1.057 1.760 0.292 0.277 0.445 0.475 0.361

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88 Table A-3. Continued Oyster 1Top 2Top 3Top 4Top 5Top 1Bottom 2Bottom 3Bottom 4Bottom 5Bottom 85 0.241 0.404 0.305 0.597 0.345 0.160 0.511 0.330 0.290 0.203 86 0.279 0.292 0.465 0.401 0.406 0.429 0.269 0.432 0.523 0.533 87 0.315 0.610 0.485 0.417 0.378 0.292 0.389 0.292 0.358 0.333 88 0.376 0.612 1.026 0.394 0.625 0.333 0.462 1.039 1.095 0.434 89 0.257 0.432 0.528 0.417 0.373 0.622 0.274 0.384 0.409 0.371 90 0.544 0.536 0.546 0.815 0.521 0.729 0.450 0.457 0.678 0.556 91 0.467 0.396 0.828 0.546 0.269 0.226 0.533 0.574 0.716 0.533 92 0.381 0.356 0.353 0.330 0.211 0.310 0.229 0.305 0.229 0.269 93 0.391 0.445 0.767 0.310 0.546 0.338 0.284 0.262 0.556 0.432 94 0.282 0.216 0.422 0.556 0.427 0.290 0.538 0.290 0.351 0.312 95 0.206 0.282 0.381 0.541 0.274 0.292 0.424 0.274 0.226 0.338 96 0.549 0.582 0.701 0.711 0.366 0.279 0.681 0.361 0.688 0.549 97 0.279 0.193 0.678 0.518 0.264 0.221 0.284 0.579 0.396 0.216 98 0.323 0.231 0.541 0.283 0.726 0.472 0.351 0.320 0.432 0.279 99 0.419 0.429 0.406 0.409 0.640 0.330 0.518 0.462 0.338 0.318 100 0.417 0.465 0.795 0.333 0.371 0.345 0.485 0.683 0.333 0.259 Clam Measurements Table A-4. Clam Weight M easurements in g (4/29/05) Clam Overall wt Meat wt Shell wt Top Shell wt Bottom Shell wt Shell/ Meat Top/ Bottom Top/ Meat Bottom/ Meat 1 36.6 8.5 28.1 14.0 14.1 3.31 0.99 1.65 1.66 2 33.5 10.6 22.9 11.4 11.5 2.16 0.99 1.08 1.08 3 40.6 10.6 30.0 15.0 15.0 2.83 1.00 1.42 1.42 4 37.8 9.8 28.0 14.1 13.9 2.86 1.01 1.44 1.42 5 38.4 11.8 26.6 13.3 13.3 2.25 1.00 1.13 1.13 6 33.5 10.3 23.2 11.4 11.8 2.25 0.97 1.11 1.15 7 37.8 11.5 26.3 13.3 13.0 2.29 1.02 1.16 1.13 8 39.5 13.7 25.8 13.0 12.8 1.88 1.02 0.95 0.93 9 47.2 14.3 32.9 16.3 16.6 2.30 0.98 1.14 1.16 10 44.3 15.5 28.8 14.5 14.3 1.86 1.01 0.94 0.92 11 42.8 14.4 28.4 14.3 14.1 1.97 1.01 0.99 0.98 12 46.0 13.9 32.1 16.0 16.1 2.31 0.99 1.15 1.16 13 40.4 13.9 26.5 13.3 13.2 1.91 1.01 0.96 0.95 14 38.7 12.0 26.7 13.4 13.3 2.23 1.01 1.12 1.11 15 30.3 8.6 21.7 11.0 10.7 2.52 1.03 1.28 1.24 16 41.2 13.3 27.9 14.0 13.9 2.10 1.01 1.05 1.05 17 39.7 11.8 27.9 14.0 13.9 2.36 1.01 1.19 1.18 18 40.4 15.1 25.3 12.7 12.6 1.68 1.01 0.84 0.83 19 43.1 12.4 30.7 15.3 15.4 2.48 0.99 1.23 1.24 20 38.4 10.9 27.5 13.9 13.6 2.52 1.02 1.28 1.25 21 49.1 15.1 34.0 17.3 16.7 2.25 1.04 1.15 1.11 22 60.1 18.6 41.5 20.6 20.9 2.23 0.99 1.11 1.12 23 36.3 11.4 24.9 12.4 12.5 2.18 0.99 1.09 1.10 24 35.6 12.5 23.1 11.6 11.5 1.85 1.01 0.93 0.92 25 39.1 11.3 27.8 14.0 13.8 2.46 1.01 1.24 1.22 26 44.9 16.2 28.7 143 14.3 1.77 10.00 8.83 0.88 27 46.0 15.3 30.7 15.4 15.3 2.01 1.01 1.01 1.00 28 35.7 9.6 26.1 13.0 13.1 2.72 0.99 1.35 1.36 29 37.2 10.1 27.1 13.5 13.6 2.68 0.99 1.34 1.35

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89 Table A-4. Continued Clam Overall wt Meat wt Shell wt Top Shell wt Bottom Shell wt Shell/ Meat Top/ Bottom Top/ Meat Bottom/ Meat 30 36.5 10.3 26.2 13.0 13.2 2.54 0.98 1.26 1.28 31 36.9 11.6 25.3 12.6 12.7 2.18 0.99 1.09 1.09 32 38.9 12.1 26.8 13.5 13.3 2.21 1.02 1.12 1.10 33 35.0 12.8 22.2 11.2 11.0 1.73 1.02 0.88 0.86 34 42.7 13.8 28.9 14.4 14.5 2.09 0.99 1.04 1.05 35 48.3 16.9 31.4 15.5 15.9 1.86 0.97 0.92 0.94 36 42.8 13.9 28.9 14.3 14.6 2.08 0.98 1.03 1.05 37 36.2 11.8 24.4 12.0 12.4 2.07 0.97 1.02 1.05 38 50.0 15.2 34.8 17.2 17.6 2.29 0.98 1.13 1.16 39 37.1 8.8 28.3 14.2 14.1 3.22 1.01 1.61 1.60 40 39.1 12.6 26.5 13.4 13.1 2.10 1.02 1.06 1.04 41 45.5 13.5 32.0 16.0 16.0 2.37 1.00 1.19 1.19 42 37.3 13.8 23.5 12.0 11.5 1.70 1.04 0.87 0.83 43 48.3 12.0 36.3 18.0 18.3 3.03 0.98 1.50 1.53 44 39.5 12.4 27.1 13.7 13.4 2.19 1.02 1.10 1.08 45 40.2 13.8 26.4 13.0 13.4 1.91 0.97 0.94 0.97 46 34.1 10.5 23.6 11.6 12.0 2.25 0.97 1.10 1.14 47 32.5 11.9 20.6 10.3 10.3 1.73 1.00 0.87 0.87 48 42.9 11.7 31.2 15.4 15.8 2.67 0.97 1.32 1.35 49 33.6 10.6 23.0 11.4 11.6 2.17 0.98 1.08 1.09 50 49.3 16.0 33.3 16.5 16.8 2.08 0.98 1.03 1.05 51 36.0 11.9 24.1 12.0 12.1 2.03 0.99 1.01 1.02 52 37.2 12.3 24.9 12.3 12.6 2.02 0.98 1.00 1.02 53 35.8 11.7 24.1 12.0 12.1 2.06 0.99 1.03 1.03 54 45.7 15.4 30.3 15.2 15.1 1.97 1.01 0.99 0.98 55 44.2 12.9 31.3 15.5 15.8 2.43 0.98 1.20 1.22 56 40.4 12.5 27.9 14.0 13.9 2.23 1.01 1.12 1.11 57 33.9 8.4 25.5 12.8 12.7 3.04 1.01 1.52 1.51 58 37.9 11.0 26.9 13.5 13.4 2.45 1.01 1.23 1.22 59 38.5 10.8 27.7 13.9 13.8 2.56 1.01 1.29 1.28 60 26.9 7.1 19.8 10.0 9.8 2.79 1.02 1.41 1.38 61 38.0 10.4 27.6 13.8 13.8 2.65 1.00 1.33 1.33 62 47.7 14.9 32.8 16.5 16.3 2.20 1.01 1.11 1.09 63 36.2 10.6 25.6 13.0 12.6 2.42 1.03 1.23 1.19 64 34.9 9.4 25.5 12.8 12.7 2.71 1.01 1.36 1.35 65 40.0 11.3 28.7 14.4 14.3 2.54 1.01 1.27 1.27 66 42.5 13.3 29.2 14.7 14.5 2.20 1.01 1.11 1.09 67 35.6 9.9 25.7 12.9 12.8 2.60 1.01 1.30 1.29 68 32.7 11.0 21.7 10.9 10.8 1.97 1.01 0.99 0.98 69 46.2 13.0 33.2 16.7 16.5 2.55 1.01 1.28 1.27 70 47.2 17.0 30.2 15.3 14.9 1.78 1.03 0.90 0.88 71 52.6 16.1 36.5 18.1 18.4 2.27 0.98 1.12 1.14 72 38.6 12.6 26.0 13.3 12.7 2.06 1.05 1.06 1.01 73 41.5 11.9 29.6 15.1 14.5 2.49 1.04 1.27 1.22 74 43.3 13.3 30.0 15.0 15.0 2.26 1.00 1.13 1.13 75 46.0 13.4 32.6 16.2 16.4 2.43 0.99 1.21 1.22 76 42.1 13.2 28.9 14.3 14.6 2.19 0.98 1.08 1.11 77 39.9 14.3 25.6 13.0 12.6 1.79 1.03 0.91 0.88 78 36.0 9.5 26.5 13.3 13.2 2.79 1.01 1.40 1.39 79 41.5 13.4 28.1 14.2 13.9 2.10 1.02 1.06 1.04

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90 Table A-4. Continued Clam Overall wt Meat wt Shell wt Top Shell wt Bottom Shell wt Shell/ Meat Top/ Bottom Top/ Meat Bottom/ Meat 80 39.8 13.3 26.5 13.4 13.1 1.99 1.02 1.01 0.98 81 51.1 14.7 36.4 18.3 18.1 2.48 1.01 1.24 1.23 82 42.8 14.4 28.4 14.4 14.0 1.97 1.03 1.00 0.97 83 44.2 16.1 28.1 14.2 13.9 1.75 1.02 0.88 0.86 84 43.8 13.4 30.4 15.4 15.0 2.27 1.03 1.15 1.12 85 37.9 12.3 25.6 13.0 12.6 2.08 1.03 1.06 1.02 86 47.4 13.9 33.5 17.0 16.5 2.41 1.03 1.22 1.19 87 48.0 16.9 31.1 15.3 15.8 1.84 0.97 0.91 0.93 88 42.6 13.8 28.8 14.2 14.6 2.09 0.97 1.03 1.06 89 51.1 16.8 34.3 17.0 17.3 2.04 0.98 1.01 1.03 90 36.8 13.9 22.9 11.6 11.3 1.65 1.03 0.83 0.81 91 34.1 12.4 21.7 10.9 10.8 1.75 1.01 0.88 0.87 92 32.5 10.8 21.7 10.9 10.8 2.01 1.01 1.01 1.00 93 45.8 14.8 31.0 15.6 15.4 2.09 1.01 1.05 1.04 94 55.1 18.9 36.2 18.0 18.2 1.92 0.99 0.95 0.96 95 35.8 10.5 25.3 12.7 12.6 2.41 1.01 1.21 1.20 96 41.3 12.0 29.3 14.8 14.5 2.44 1.02 1.23 1.21 97 38.8 12.1 26.7 13.1 13.6 2.21 0.96 1.08 1.12 98 39.5 14.2 25.3 12.8 12.5 1.78 1.02 0.90 0.88 99 35.9 9.5 26.4 13.2 13.2 2.78 1.00 1.39 1.39 100 35.4 11.9 23.5 11.8 11.7 1.97 1.01 0.99 0.98 Table A-5. Clam Dimension Measurement in cm (5/10/05) Clam Top Length Top Height Top Width Bottom Length Bottom Height Bottom Width Total Length Total Height Total Width 1 4.45 1.45 4.95 4.5 1.4 4.95 4.5 2.85 4.95 2 4.4 1.45 5.0 4.35 1.35 5.0 4.4 2.8 5.0 3 4.6 1.45 5.1 4.55 1.5 5.1 4.6 2.95 5.1 4 4.3 1.5 5.2 4.45 1.45 5.25 4.45 2.95 5.25 5 4.2 1.45 4.9 4.2 1.4 4.8 4.2 2.85 4.9 6 4.0 1.45 4.6 4.15 1.45 4.55 4.15 2.9 4.6 7 4.15 1.35 4.9 4.2 1.45 4.9 4.2 2.8 4.9 8 4.35 1.4 4.85 4.4 1.45 4.85 4.4 2.85 4.85 9 4.4 1.5 5.4 4.5 1.5 5.4 4.5 3.0 5.4 10 4.3 1.45 5.2 4.55 1.45 5.2 4.55 2.9 5.2 11 4.5 1.5 4.95 4.4 1.4 5.0 4.5 2.9 5.0 12 4.4 1.45 5.25 4.3 1.35 5.15 4.4 2.8 5.25 13 4.3 1.45 5.05 4.2 1.5 5.1 4.3 2.95 5.1 14 4.3 1.45 4.8 4.35 1.45 4.85 4.35 2.9 4.85 15 3.8 1.5 4.45 3.8 1.35 4.5 3.8 2.85 4.5 16 4.3 1.35 4.8 4.35 1.4 4.75 4.35 2.75 4.8 17 4.1 1.5 4.9 4.3 1.55 4.9 4.3 3.05 4.9 18 4.0 1.4 4.6 4.0 1.4 4.7 4.0 2.8 4.7 19 4.8 1.4 5.45 4.8 1.3 5.4 4.8 2.7 5.45 20 4.4 1.45 5.1 4.3 1.45 5.05 4.4 2.9 5.1 21 4.75 1.45 5.5 4.75 1.4 5.5 4.75 2.85 5.5 22 4.7 1.5 5.9 4.85 1.6 5.9 4.85 3.1 5.9 23 4.1 1.4 4.9 4.1 1.45 4.85 4.1 2.85 4.9 24 4.4 1.4 4.9 4.3 1.4 4.85 4.4 2.8 4.9 25 4.45 1.4 4.85 4.4 1.45 4.8 4.45 2.85 4.85

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91 Table A-5. Continued Clam Top Length Top Height Top Width Bottom Length Bottom Height Bottom Width Total Length Total Height Total Width 26 4.1 1.4 5.15 4.2 1.4 5.1 4.2 2.8 5.15 27 4.35 1.4 5.3 4.3 1.45 5.25 4.35 2.85 5.3 28 4.0 1.4 4.85 4.0 1.35 4.85 4.0 2.75 4.85 29 4.25 1.45 4.7 4.25 1.4 4.7 4.25 2.85 4.7 30 4.15 1.5 4.95 4.35 1.55 5.0 4.35 3.05 5.0 31 4.1 1.45 4.9 4.1 1.3 4.8 4.1 2.75 4.9 32 4.35 1.4 5.05 4.3 1.4 5.05 4.35 2.8 5.05 33 3.95 1.3 4.5 4.0 1.35 4.5 4.0 2.65 4.5 34 4.35 1.3 4.95 4.35 1.5 4.95 4.35 2.8 4.95 35 4.7 1.5 5.2 4.55 1.6 5.2 4.7 3.1 5.2 36 4.55 1.45 5.2 4.6 1.35 5.2 4.6 2.8 5.2 37 4.05 1.4 4.9 4.2 1.4 4.9 4.2 2.8 4.9 38 4.6 1.4 5.4 4.4 1.5 5.25 4.6 2.9 5.4 39 4.15 1.55 4.8 4.25 1.5 4.8 4.25 3.05 4.8 40 4.35 1.4 4.8 4.3 1.4 4.8 4.35 2.8 4.8 41 4.4 1.5 5.1 4.45 1.4 5.2 4.45 2.9 5.2 42 4.5 1.4 5.0 4.4 1.4 4.95 4.5 2.8 5.0 43 4.6 1.45 5.4 4.8 1.4 4.45 4.8 2.85 5.4 44 4.2 1.4 4.8 4.25 1.45 4.8 4.25 2.85 4.8 45 4.15 1.35 4.8 4.3 1.4 4.85 4.3 2.75 4.85 46 4.05 1.45 4.8 4.2 1.3 4.75 4.2 2.75 4.8 47 4.0 1.2 4.4 4.05 1.45 4.45 4.05 2.65 4.45 48 4.35 1.55 5.0 4.35 1.5 5.05 4.35 3.05 5.05 49 4.0 1.4 4.7 4.1 1.2 4.7 4.1 2.6 4.7 50 4.4 1.4 5.4 4.5 1.55 5.35 4.5 2.95 5.4 51 4.0 1.5 4.4 3.95 1.45 4.5 4.0 2.95 4.5 52 4.05 1.4 5.0 4.05 1.4 4.9 4.05 2.8 5.0 53 3.95 1.35 4.9 4.05 1.3 4.9 4.05 2.65 4.9 54 4.35 1.45 5.15 4.55 1.45 5.2 4.55 2.9 5.2 55 4.3 1.55 5.3 4.45 1.5 5.25 4.45 3.05 5.3 56 4.25 1.4 5.05 4.2 1.35 5.05 4.25 2.75 5.05 57 4.3 1.45 4.95 4.1 1.4 4.95 4.3 2.85 4.95 58 4.25 1.4 4.85 4.3 1.4 4.9 4.3 2.8 4.9 59 4.2 1.5 4.75 4.2 1.4 4.75 4.2 2.9 4.75 60 4.0 1.25 4.3 3.95 1.4 4.35 4.0 2.65 4.35 61 4.3 1.4 4.9 4.25 1.55 4.9 4.3 2.95 4.9 62 4.6 1.6 5.1 4.65 1.65 5.15 4.65 3.25 5.15 63 4.1 1.35 4.7 4.2 1.4 4.7 4.2 2.75 4.7 64 4.20 1.4 4.95 4.25 1.3 4.55 4.25 2.7 4.95 65 4.45 1.4 4.9 4.4 1.4 4.9 4.45 2.8 4.9 66 4.3 1.6 4.85 4.4 1.5 5.0 4.4 3.1 5.0 67 4.45 1.4 4.9 4.45 1.45 4.9 4.45 2.85 4.9 68 4.0 1.35 4.5 4.0 1.35 4.5 4.0 2.7 4.5 69 4.5 1.5 5.0 4.55 1.5 5.0 4.55 3.0 5.0 70 4.1 1.4 4.8 4.15 1.45 4.8 4.15 2.85 4.8 71 4.6 1.5 5.25 4.6 1.5 5.3 4.6 3.0 5.3 72 4.6 1.4 5.5 4.6 1.3 5.5 4.6 2.7 5.5 73 4.35 1.3 4.9 4.2 1.35 4.9 4.35 2.65 4.9 74 4.45 1.4 5.0 4.4 1.4 5.0 4.45 2.8 5.0 75 4.3 1.45 5.0 4.35 1.4 5.0 4.35 2.85 5.0

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92 Table A-5. Continued Clam Top Length Top Height Top Width Bottom Length Bottom Height Bottom Width Total Length Total Height Total Width 76 4.35 1.3 4.8 4.4 1.25 4.9 4.4 2.55 4.9 77 4.05 1.35 4.85 4.1 1.35 4.85 4.1 2.7 4.85 78 4.0 1.4 4.55 4.05 1.4 4.5 4.05 2.8 4.55 79 4.05 1.3 4.9 4.1 1.35 4.95 4.1 2.65 4.95 80 4.2 1.4 5.0 4.3 1.45 4.95 4.3 2.85 5.0 81 4.5 1.5 5.3 4.9 1.4 5.2 4.9 2.9 5.3 82 4.45 1.35 5.0 4.5 1.45 5.0 4.5 2.8 5.0 83 4.4 1.5 5.0 4.4 1.4 5.05 4.4 2.9 5.05 84 4.15 1.45 4.7 4.2 1.45 4.7 4.2 2.9 4.7 85 4.3 1.5 4.95 4.3 1.4 4.95 4.3 2.9 4.95 86 4.75 1.4 5.4 4.7 1.45 5.4 4.75 2.85 5.4 87 4.4 1.45 5.3 4.5 1.45 5.35 4.5 2.9 5.35 88 4.2 1.35 4.9 4.3 1.35 4.9 4.3 2.7 4.9 89 4.65 1.45 5.4 4.7 1.45 5.4 4.7 2.9 5.4 90 4.15 1.35 4.6 4.03 1.4 4.6 4.15 2.75 4.6 91 4.0 1.2 4.3 4.0 1.45 4.5 4.0 2.65 4.5 92 4.0 1.4 4.65 4.0 1.4 4.65 4.0 2.8 4.65 93 4.7 1.2 5.25 4.55 1.5 5.2 4.7 2.7 4.25 94 4.7 1.45 5.4 4.6 1.5 5.25 4.7 2.95 5.4 95 4.0 1.3 4.55 4.0 1.35 4.5 4.0 2.65 4.55 96 4.2 1.5 4.75 4.2 1.55 4.75 4.2 3.05 4.75 97 4.2 1.35 4.95 4.2 1.4 4.85 4.2 2.75 4.95 98 4.1 1.4 4.8 4.2 1.3 4.8 4.2 2.7 4.8 99 4.3 1.4 4.8 4.75 1.45 4.8 4.75 2.85 4.8 100 4.15 1.4 4.45 4.0 1.3 4.5 4.15 2.7 4.5 Table A-6. Clam Thickness Measurement in cm (5/12/05) Clam 1Top 2Top 3Top 4Top 5Top 1Bottom 2Bottom 3Bottom 4Bottom 5Bottom 1 0.29 0.33 0.32 0.33 0.34 0.28 0.37 0.34 0.35 0.30 2 0.24 0.28 0.26 0.32 0.34 0.26 0.32 0.31 0.31 0.31 3 0.30 0.29 0.33 0.30 0.34 0.29 0.33 0.32 0.33 0.33 4 0.28 0.30 0.28 0.37 0.36 0.29 0.31 0.30 0.36 0.35 5 0.28 0.27 0.28 0.26 0.27 0.27 0.27 0.25 0.27 0.26 6 0.27 0.31 0.29 0.32 0.34 0.27 0.31 0.30 0.32 0.31 7 0.27 0.32 0.33 0.31 0.31 0.28 0.31 0.32 0.31 0.34 8 0.26 0.30 0.30 0.34 0.34 0.27 0.32 0.30 0.31 0.32 9 0.31 0.31 0.33 0.35 0.34 0.30 0.37 0.34 0.33 0.33 10 0.27 0.31 0.27 0.31 0.32 0.26 0.35 0.32 0.31 0.33 11 0.27 0.30 0.29 0.34 0.30 0.27 0.33 0.31 0.33 0.33 12 0.30 0.30 0.32 0.36 0.37 0.28 0.35 0.31 0.38 0.38 13 0.29 0.27 0.29 0.27 0.28 0.27 0.28 0.27 0.34 0.34 14 0.28 0.28 0.31 0.30 0.30 0.31 0.29 0.31 0.35 0.35 15 0.26 0.30 0.29 0.33 0.33 0.26 0.31 0.31 0.33 0.32 16 0.29 0.29 0.35 0.36 0.32 0.30 0.38 0.33 0.32 0.37 17 0.27 0.29 0.31 0.36 0.34 0.27 0.32 0.31 0.35 0.36 18 0.28 0.29 0.35 0.32 0.33 0.26 0.34 0.36 0.35 0.35 19 0.24 0.26 0.27 0.28 0.28 0.26 0.26 0.31 0.30 0.29 20 0.26 0.27 0.32 0.29 0.28 0.26 0.36 0.32 0.28 0.27 21 0.27 0.30 0.30 0.28 0.28 0.27 0.29 0.31 0.27 0.27 22 0.29 0.32 0.33 0.30 0.32 0.28 0.30 0.31 0.31 0.32

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93 Table A-6. Continued Clam 1Top 2Top 3Top 4Top 5Top 1Bottom 2Bottom 3Bottom 4Bottom 5Bottom 23 0.27 0.27 0.31 0.30 0.30 0.27 0.32 0.31 0.31 0.30 24 0.26 0.30 0.31 0.28 0.29 0.27 0.31 0.27 0.32 0.30 25 0.26 0.30 0.30 0.32 0.32 0.26 0.28 0.29 0.31 0.31 26 0.28 0.27 0.31 0.30 0.30 0.28 0.32 0.30 0.30 0.33 27 0.28 0.27 0.32 0.28 0.29 0.31 0.37 0.34 0.36 0.35 28 0.26 0.32 0.27 0.29 0.28 0.25 0.31 0.26 0.29 0.29 29 0.26 0.30 0.28 0.32 0.29 0.28 0.26 0.29 0.29 0.28 30 0.28 0.28 0.30 0.30 0.30 0.28 0.29 0.29 0.33 0.33 31 0.28 0.27 0.31 0.26 0.25 0.28 0.27 0.30 0.25 0.25 32 0.27 0.28 0.30 0.27 0.27 0.25 0.28 0.31 0.27 0.26 33 0.25 0.28 0.27 0.28 0.27 0.25 0.28 0.27 0.27 0.27 34 0.25 0.28 0.31 0.26 0.26 0.25 0.27 0.31 0.26 0.26 35 0.29 0.29 0.33 0.37 0.37 0.27 0.31 0.31 0.33 0.37 36 0.27 0.26 0.30 0.25 0.27 0.26 0.27 0.31 0.27 0.26 37 0.26 0.30 0.28 0.27 0.27 0.26 0.28 0.31 0.26 0.26 38 0.27 0.29 0.31 0.29 0.31 0.31 0.25 0.30 0.30 0.31 39 0.28 0.30 0.32 0.33 0.34 0.28 0.36 0.34 0.34 0.34 40 0.26 0.32 0.34 0.30 0.30 0.28 0.32 0.32 0.29 0.28 41 0.27 0.28 0.31 0.28 0.28 0.27 0.28 0.32 0.27 0.27 42 0.27 0.29 0.32 0.26 0.26 0.29 0.27 0.27 0.27 0.00 43 0.27 0.28 0.31 0.28 0.28 0.26 0.28 0.32 0.27 0.27 44 0.28 0.26 0.31 0.28 0.28 0.27 0.26 0.30 0.27 0.28 45 0.27 0.28 0.31 0.29 0.29 0.30 0.31 0.30 0.28 0.30 46 0.27 0.26 0.30 0.25 0.27 0.26 0.25 0.30 0.29 0.30 47 0.26 0.29 0.31 0.26 0.26 0.26 0.29 0.31 0.26 0.26 48 0.27 0.29 0.32 0.32 0.32 0.28 0.28 0.31 0.30 0.30 49 0.26 0.30 0.31 0.30 0.30 0.26 0.31 0.30 0.28 0.31 50 0.28 0.34 0.32 0.28 0.28 0.28 0.33 0.31 0.29 0.29 51 0.26 0.26 0.33 0.25 0.26 0.28 0.26 0.32 0.26 0.26 52 0.27 0.26 0.30 0.27 0.27 0.26 0.26 0.31 0.27 0.27 53 0.26 0.32 0.27 0.29 0.28 0.25 0.31 0.26 0.29 0.29 54 0.27 0.26 0.30 0.28 0.28 0.27 0.26 0.30 0.28 0.28 55 0.28 0.27 0.29 0.27 0.28 0.26 0.31 0.31 0.26 0.27 56 0.26 0.30 0.29 0.30 0.30 0.27 0.28 0.29 0.27 0.28 57 0.27 0.28 0.31 0.28 0.29 0.26 0.27 0.31 0.28 0.28 58 0.28 0.32 0.31 0.30 0.30 0.28 0.28 0.31 0.31 0.30 59 0.26 0.27 0.32 0.26 0.26 0.26 0.27 0.31 0.28 0.28 60 0.25 0.31 0.27 0.31 0.30 0.26 0.30 0.27 0.27 0.26 61 0.28 0.27 0.31 0.26 0.26 0.28 0.26 0.32 0.26 0.26 62 0.27 0.30 0.30 0.30 0.30 0.26 0.31 0.29 0.30 0.30 63 0.25 0.28 0.33 0.31 0.30 0.26 0.28 0.32 0.29 0.29 64 0.27 0.29 0.30 0.28 0.28 0.26 0.30 0.31 0.27 0.27 65 0.26 0.28 0.30 0.33 0.33 0.26 0.27 0.27 0.34 0.35 66 0.32 0.29 0.27 0.26 0.26 0.29 0.27 0.27 0.27 0.27 67 0.27 0.28 0.30 0.27 0.27 0.25 0.28 0.31 0.27 0.26 68 0.25 0.26 0.28 0.27 0.27 0.24 0.27 0.30 0.26 0.27 69 0.26 0.32 0.35 0.32 0.31 0.25 0.31 0.34 0.31 0.31 70 0.29 0.25 0.29 0.31 0.31 0.28 0.26 0.31 0.30 0.30 71 0.26 0.27 0.27 0.31 0.32 0.25 0.27 0.28 0.30 0.31 72 0.30 0.31 0.32 0.32 0.32 0.26 0.30 0.32 0.31 0.31

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94 Table A-6. Continued Clam 1Top 2Top 3Top 4Top 5Top 1Bottom 2Bottom 3Bottom 4Bottom 5Bottom 73 0.31 0.30 0.34 0.32 0.32 0.31 0.31 0.33 0.37 0.36 74 0.30 0.27 0.32 0.27 0.27 0.29 0.27 0.32 0.30 0.31 75 0.26 0.31 0.29 0.30 0.30 0.25 0.30 0.28 0.30 0.30 76 0.27 0.28 0.33 0.30 0.29 0.27 0.28 0.32 0.29 0.29 77 0.26 0.30 0.28 0.35 0.34 0.26 0.30 0.27 0.32 0.32 78 0.25 0.31 0.33 0.30 0.29 0.26 0.30 0.31 0.28 0.30 79 0.25 0.28 0.27 0.28 0.27 0.25 0.28 0.27 0.27 0.27 80 0.26 0.29 0.30 0.30 0.30 0.25 0.28 0.29 0.29 0.30 81 0.29 0.32 0.34 0.30 0.30 0.28 0.32 0.32 0.29 0.28 82 0.28 0.27 0.30 0.29 0.29 0.27 0.27 0.28 0.29 0.29 83 0.28 0.33 0.32 0.36 0.34 0.27 0.33 0.32 0.32 0.32 84 0.28 0.29 0.33 0.30 0.30 0.27 0.29 0.31 0.30 0.30 85 0.27 0.28 0.26 0.28 0.28 0.26 0.27 0.27 0.28 0.28 86 0.28 0.27 0.31 0.31 0.31 0.28 0.27 0.29 0.31 0.31 87 0.23 0.28 0.29 0.28 0.29 0.26 0.27 0.31 0.28 0.28 88 0.30 0.35 0.33 0.31 0.32 0.30 0.36 0.33 0.32 0.31 89 0.27 0.28 0.31 0.28 0.28 0.27 0.28 0.32 0.27 0.27 90 0.26 0.26 0.27 0.31 0.31 0.26 0.30 0.27 0.28 0.32 91 0.25 0.29 0.32 0.31 0.31 0.26 0.28 0.31 0.31 0.31 92 0.25 0.25 0.28 0.26 0.26 0.25 0.26 0.28 0.26 0.26 93 0.27 0.32 0.32 0.32 0.32 0.27 0.32 0.28 0.31 0.33 94 0.27 0.28 0.31 0.28 0.28 0.26 0.28 0.32 0.27 0.27 95 0.29 0.32 0.31 0.32 0.32 0.28 0.33 0.35 0.34 0.32 96 0.30 0.32 0.32 0.35 0.35 0.29 0.31 0.31 0.35 0.32 97 0.28 0.30 0.30 0.28 0.28 0.27 0.27 0.30 0.27 0.27 98 0.28 0.33 0.28 0.32 0.32 0.28 0.32 0.31 0.32 0.32 99 0.28 0.33 0.30 0.31 0.34 0.28 0.29 0.30 0.31 0.31 100 0.25 0.26 0.28 0.27 0.27 0.26 0.30 0.26 0.29 0.30 Mussel Measurement Table A-7. Mussel Weight M easurement in g (5/12/05) Mussel Overall Wt Meat Wt Shell Wt Top Shell wt Bottom Shell wt Shell/ Meat Top/ Bottom Top/ Meat Bottom/ Meat 1 22.9 13.4 9.5 5.0 4.5 0.71 1.11 0.37 0.34 2 19.6 10.7 8.9 4.45 4.45 0.83 1.00 0.42 0.42 3 17 9.2 7.8 3.8 4 0.85 0.95 0.41 0.43 4 10.7 6.6 4.1 2.05 2.05 0.62 1.00 0.31 0.31 5 18.6 12.1 6.5 3.3 3.2 0.54 1.03 0.27 0.26 6 14.2 6.4 7.8 3.7 4.1 1.22 0.90 0.58 0.64 7 10.9 5.0 5.9 3.1 2.8 1.18 1.11 0.62 0.56 8 14.4 8.2 6.2 3.3 2.9 0.76 1.14 0.40 0.35 9 11.7 6.8 4.9 2.5 2.4 0.72 1.04 0.37 0.35 10 15.9 10.0 5.9 3.1 2.8 0.59 1.11 0.31 0.28 11 14.3 7.0 7.3 3.65 3.65 1.04 1.00 0.52 0.52 12 15.3 8.2 7.1 3.4 3.7 0.87 0.92 0.41 0.45 13 23.8 14.5 9.3 4.4 4.9 0.64 0.90 0.30 0.34 14 18.8 10.9 7.9 3.8 4.1 0.72 0.93 0.35 0.38 15 17.2 10.4 6.8 3.6 3.2 0.65 1.13 0.35 0.31 16 15.6 9.1 6.5 3.25 3.25 0.71 1.00 0.36 0.36

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95 Table A-7. Continued Mussel Overall Wt Meat Wt Shell Wt Top Shell wt Bottom Shell wt Shell/ Meat Top/ Bottom Top/ Meat Bottom/ Meat 17 14.3 7.3 7.0 3.0 4 0.96 0.75 0.41 0.55 18 22.1 13.1 9.0 4.2 4.8 0.69 0.88 0.32 0.37 19 12.8 6.6 6.2 3 3.2 0.94 0.94 0.45 0.48 20 15.7 9.7 6.0 3.2 2.8 0.62 1.14 0.33 0.29 21 17.6 11.2 6.4 3.2 3.2 0.57 1.00 0.29 0.29 22 10.3 5.4 4.9 2.6 2.3 0.91 1.13 0.48 0.43 23 18.2 10.3 7.9 3.80 4.1 0.77 0.93 0.37 0.40 24 13.9 8.4 5.5 2.75 2.75 0.65 1.00 0.33 0.33 25 16.8 9.5 7.3 3.8 3.5 0.77 1.09 0.40 0.37 26 8.3 4.0 4.3 2.3 2 1.08 1.15 0.58 0.50 27 27.6 14.6 13.0 6.8 6.2 0.89 1.10 0.47 0.42 28 21.1 11.9 9.2 4.6 4.6 0.77 1.00 0.39 0.39 29 10.1 5.2 4.9 2.6 2.3 0.94 1.13 0.50 0.44 30 15.4 6.6 8.8 4.4 4.4 1.33 1.00 0.67 0.67 31 18.9 11.2 7.7 4.0 3.7 0.69 1.08 0.36 0.33 32 15.4 8.6 6.8 3.6 3.2 0.79 1.13 0.42 0.37 33 15.7 8.0 7.7 4.0 3.7 0.96 1.08 0.50 0.46 34 18.4 7.2 11.2 5.6 5.6 1.56 1.00 0.78 0.78 35 22.7 10.3 12.4 6.0 6.4 1.20 0.94 0.58 0.62 36 12.2 6.1 6.1 3.2 2.9 1.00 1.10 0.52 0.48 37 16.3 8.1 8.2 4.3 3.9 1.01 1.10 0.53 0.48 38 9.1 4.7 4.4 2.5 1.9 0.94 1.32 0.53 0.40 39 10.5 4.8 5.7 2.9 2.8 1.19 1.04 0.60 0.58 40 13.5 6.6 6.9 3.1 3.8 1.05 0.82 0.47 0.58 41 10.8 5.6 5.2 3.0 2.2 0.93 1.36 0.54 0.39 42 13.2 6.0 7.2 3.7 3.5 1.20 1.06 0.62 0.58 43 13.1 6.8 6.3 3.4 2.9 0.93 1.17 0.50 0.43 44 10.4 3.7 6.7 3.5 3.2 1.81 1.09 0.95 0.86 45 13.4 6.7 6.7 3.2 3.5 1.00 0.91 0.48 0.52 46 11.3 4.7 6.6 3.1 3.5 1.40 0.89 0.66 0.74 47 7.6 3.1 4.5 2.2 2.3 1.45 0.96 0.71 0.74 48 8.5 3.0 5.5 2.75 2.75 1.83 1.00 0.92 0.92 49 10.9 4.6 6.3 3.0 3.3 1.37 0.91 0.65 0.72 50 9.2 3.7 5.5 2.9 2.6 1.49 1.12 0.78 0.70 51 12.2 5.9 6.3 3.0 3.3 1.07 0.91 0.51 0.56 52 14.8 8.1 6.7 3.3 3.4 0.83 0.97 0.41 0.42 53 11.6 5.6 6.0 3.1 2.9 1.07 1.07 0.55 0.52 54 12.8 5.8 7.0 3.1 3.9 1.21 0.79 0.53 0.67 55 11.2 6.0 5.2 2.9 2.3 0.87 1.26 0.48 0.38 56 9.3 3.9 5.4 3.0 2.4 1.38 1.25 0.77 0.62 57 16.7 7.9 8.8 4.1 4.7 1.11 0.87 0.52 0.59 58 8.8 3.9 4.9 2.3 2.6 1.26 0.88 0.59 0.67 59 8.3 3.0 5.3 2.65 2.65 1.77 1.00 0.88 0.88 60 9.5 4.5 5.0 2.5 2.5 1.11 1.00 0.56 0.56 61 10.1 5.3 4.8 2.7 2.1 0.91 1.29 0.51 0.40 62 7.6 2.8 4.8 2.0 2.8 1.71 0.71 0.71 1.00 63 9.9 4.4 5.5 2.75 2.75 1.25 1.00 0.63 0.63 64 9.3 4.2 5.1 2.4 2.7 1.21 0.89 0.57 0.64 65 10.4 4.3 6.1 2.9 3.2 1.42 0.91 0.67 0.74 66 11.1 5.3 5.8 3.1 2.7 1.09 1.15 0.58 0.51

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96 Table A-7. Continued Mussel Overall Wt Meat Wt Shell Wt Top Shell wt Bottom Shell wt Shell/ Meat Top/ Bottom Top/ Meat Bottom/ Meat 68 11.3 4.0 7.3 3.6 3.7 1.83 0.97 0.90 0.93 69 8.7 3.5 5.2 2.4 2.8 1.49 0.86 0.69 0.80 70 11.7 4.9 6.8 3.6 3.2 1.39 1.13 0.73 0.65 71 10.8 3.9 6.9 3.3 3.6 1.77 0.92 0.85 0.92 72 8.8 4.2 4.6 2.3 2.3 1.10 1.00 0.55 0.55 73 8.5 3.7 4.8 2.4 2.4 1.30 1.00 0.65 0.65 74 8.2 3.4 4.8 2.5 2.3 1.41 1.09 0.74 0.68 75 11.1 4.6 6.5 3.3 3.2 1.41 1.03 0.72 0.70 76 7.7 3.4 4.3 2.3 2 1.26 1.15 0.68 0.59 77 18.6 9.8 8.8 4.1 4.7 0.90 0.87 0.42 0.48 78 10.4 4.4 6.0 3.2 2.8 1.36 1.14 0.73 0.64 79 9.1 3.0 6.1 3.0 3.1 2.03 0.97 1.00 1.03 80 14.3 8.1 6.2 2.8 3.4 0.77 0.82 0.35 0.42 81 11.4 5.0 6.4 3.2 3.2 1.28 1.00 0.64 0.64 82 9.1 4.3 4.8 2.4 2.4 1.12 1.00 0.56 0.56 83 6.3 2.0 4.3 2.15 2.15 2.15 1.00 1.08 1.08 84 6.7 2.6 4.1 2.2 1.9 1.58 1.16 0.85 0.73 85 7 2.3 4.7 2.2 2.5 2.04 0.88 0.96 1.09 86 8.4 3.5 4.9 2.3 2.6 1.40 0.88 0.66 0.74 87 9.2 3.6 5.6 2.6 3 1.56 0.87 0.72 0.83 88 10.5 4.7 5.8 2.7 3.1 1.23 0.87 0.57 0.66 89 12.3 5.5 6.8 3.1 3.7 1.24 0.84 0.56 0.67 90 10.4 4.1 6.3 3.25 3.05 1.54 1.07 0.79 0.74 91 9.6 4.9 4.7 2.1 2.6 0.96 0.81 0.43 0.53 92 6.3 1.9 4.4 2.0 2.4 2.32 0.83 1.05 1.26 93 13.9 5.4 8.5 4.1 4.4 1.57 0.93 0.76 0.81 94 8.2 2.5 5.7 2.9 2.8 2.28 1.04 1.16 1.12 95 11.6 4.0 7.6 4.0 3.6 1.90 1.11 1.00 0.90 96 12.3 4.0 8.3 4.3 4 2.08 1.08 1.08 1.00 97 8.9 3.8 5.1 2.60 2.5 1.34 1.04 0.68 0.66 98 10.9 4.3 6.6 3.3 3.3 1.53 1.00 0.77 0.77 99 8.8 3.8 5.0 2.8 2.2 1.32 1.27 0.74 0.58 100 12.8 6.7 6.1 3.2 2.9 0.91 1.10 0.48 0.43 Table A-8. Mussel Dimension Me asurement in cm (5/20/05) Mussel Top Length Top Height Top Width Bottom Length Bottom Height Bottom Width Total Length Total Height Total Width 1 6.10 2.40 2.80 6.05 2.45 2.85 6.10 4.85 2.85 2 5.50 1.15 2.75 5.50 1.15 2.70 5.50 2.30 2.75 3 6.20 1.10 2.50 6.15 1.05 2.45 6.20 2.15 2.50 4 5.95 1.20 3.45 6.00 1.00 3.45 6.00 2.20 3.45 5 4.90 1.35 3.95 4.90 1.25 3.90 4.90 2.60 3.95 6 6.70 0.95 2.95 6.80 0.95 2.90 6.80 1.90 2.95 7 5.30 1.20 3.50 5.35 1.20 3.50 5.35 2.40 3.50 8 5.25 1.00 3.75 5.25 1.00 3.80 5.25 2.00 3.80 9 5.25 1.15 3.25 5.25 1.20 3.30 5.25 2.35 3.30 10 6.05 1.10 3.15 6.15 1.15 3.15 6.15 2.25 3.15 11 6.30 1.35 2.95 6.35 1.35 2.95 6.35 2.70 2.95 12 5.50 1.45 3.65 5.50 1.45 3.65 5.50 2.90 3.65 13 4.95 1.00 3.00 5.00 1.00 3.05 5.00 2.00 3.05

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97 Table A-8 Continued Mussel Top Length Top Height Top Width Bottom Length Bottom Height Bottom Width Total Length Total Height Total Width 14 6.40 1.30 3.35 6.40 1.35 3.30 6.40 2.65 3.35 15 5.80 1.05 3.00 5.80 1.10 3.00 5.80 2.15 3.00 16 6.00 1.20 2.80 6.00 1.25 2.85 6.00 2.45 2.85 17 4.50 1.35 3.40 4.55 1.35 3.40 4.55 2.70 3.40 18 5.85 1.75 3.65 5.85 1.75 3.65 5.85 3.50 3.65 19 5.00 1.45 2.95 5.05 1.50 2.95 5.05 2.95 2.95 20 5.30 1.00 3.00 5.30 0.95 3.00 5.30 1.95 3.00 21 5.45 1.10 2.80 5.50 1.15 2.80 5.50 2.25 2.80 22 5.30 1.00 2.90 5.30 1.00 2.95 5.30 2.00 2.95 23 6.15 1.15 2.60 6.15 1.05 2.60 6.15 2.20 2.60 24 5.80 1.20 3.35 5.85 1.20 3.50 5.85 2.40 3.35 25 6.00 1.10 3.40 6.00 1.10 3.40 6.00 2.20 3.40 26 5.30 1.00 3.00 5.30 0.95 3.10 5.30 1.95 3.10 27 5.95 1.25 3.40 5.90 1.30 3.25 5.95 2.55 3.40 28 5.50 1.20 3.50 5.50 1.20 3.55 5.50 2.40 3.55 29 5.50 1.00 2.90 5.50 0.95 2.90 5.50 1.95 2.90 30 5.95 1.20 3.50 6.00 1.00 3.45 6.00 2.20 3.50 31 6.30 1.35 2.95 6.35 1.35 2.95 6.35 2.70 2.95 32 5.95 0.95 2.95 5.95 1.00 2.90 5.95 1.95 2.95 33 6.15 1.00 3.25 6.10 1.00 3.20 6.15 2.00 3.25 34 4.75 1.10 3.10 4.80 1.10 3.10 4.80 2.20 3.10 35 6.15 1.15 2.60 6.15 1.05 2.65 6.15 2.20 2.65 36 5.30 1.25 3.35 5.25 1.20 3.35 5.30 2.45 3.35 37 4.95 1.00 3.00 5.00 1.00 3.05 5.00 2.00 3.05 38 5.00 1.45 3.10 5.05 1.50 2.95 5.05 2.95 3.10 39 6.70 0.95 2.95 6.80 0.95 2.90 6.80 1.90 2.95 40 4.95 1.05 3.25 5.00 1.10 3.25 5.00 2.15 3.10 41 5.05 1.05 2.95 4.70 1.05 2.90 5.05 2.10 2.95 42 5.05 1.10 3.10 5.05 1.10 3.10 5.05 2.20 3.10 43 6.15 1.15 2.60 6.15 1.05 2.60 6.15 2.20 2.60 44 4.95 1.00 3.00 5.00 1.00 3.05 5.00 2.00 3.05 45 6.15 1.00 3.25 6.10 1.00 3.20 6.15 2.00 3.25 46 5.25 1.15 3.25 5.25 1.20 3.30 5.25 2.35 3.30 47 5.10 1.15 3.05 5.15 1.20 3.00 5.15 2.35 3.05 48 5.95 1.25 2.95 5.95 1.25 3.00 5.95 2.50 3.00 49 5.60 1.10 3.30 5.60 1.10 3.30 5.60 2.20 3.30 50 6.70 1.20 3.40 6.70 1.20 3.40 6.70 2.40 3.40 51 4.95 1.35 3.05 5.00 1.40 3.00 5.00 2.75 3.00 52 5.30 1.25 3.25 5.25 1.20 3.25 5.30 2.45 3.25 53 5.95 1.00 2.95 6.00 1.05 3.00 6.00 2.05 3.00 54 5.90 1.30 3.15 5.90 1.30 3.20 5.90 2.60 3.20 55 5.80 1.00 3.45 5.70 1.05 3.40 5.80 2.05 3.45 56 5.25 1.05 3.05 5.15 1.05 3.00 5.25 2.10 3.00 57 6.65 1.15 3.60 6.60 1.15 3.60 6.65 2.30 3.60 58 5.05 1.10 2.80 5.05 1.05 2.75 5.05 2.15 2.80 59 5.30 1.00 2.90 5.30 1.00 2.90 5.30 2.00 2.90 60 6.15 1.15 2.60 6.15 1.05 2.60 6.15 2.20 2.60 61 5.50 1.10 2.80 5.50 1.10 2.95 5.50 2.20 2.95 62 5.60 1.20 3.10 5.55 1.20 3.10 5.60 2.40 3.10 63 5.20 1.00 2.90 5.20 1.00 2.95 5.20 2.00 2.95

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98 Table A-8. Continued Mussel Top Length Top Height Top Width Bottom Length Bottom Height Bottom Width Total Length Total Height Total Width 64 6.15 1.15 2.60 6.15 1.05 2.60 6.15 2.20 2.60 65 5.85 0.95 2.50 5.80 0.95 2.35 5.85 1.90 2.50 66 6.25 1.25 3.20 6.20 1.15 3.15 6.25 2.40 3.20 67 5.80 1.00 3.45 5.70 1.05 3.40 5.80 2.05 3.45 68 6.70 1.10 3.40 6.70 1.00 3.40 6.70 2.10 3.40 69 5.30 1.00 3.10 5.25 0.95 3.15 5.30 1.95 3.15 70 4.95 0.90 2.75 4.95 0.95 2.75 4.95 1.85 2.75 71 5.05 1.40 3.20 5.00 1.45 3.20 5.05 2.85 3.20 72 6.15 1.25 3.05 6.20 1.25 3.00 6.20 2.50 3.05 73 4.95 1.40 3.00 4.90 1.45 2.80 4.95 2.85 3.00 74 5.10 1.00 2.75 5.10 1.00 2.75 5.10 2.00 2.75 75 5.85 1.05 2.65 5.90 1.10 2.70 5.90 2.15 2.70 76 6.00 1.15 2.60 6.00 1.10 2.55 6.00 2.25 2.60 77 5.05 0.95 2.35 5.10 0.90 2.30 5.10 1.85 2.53 78 4.95 1.05 3.40 5.00 1.10 3.25 5.00 2.15 3.40 79 5.40 1.30 2.50 5.45 1.35 2.50 5.45 2.65 2.50 80 5.50 1.05 3.10 5.55 1.00 3.15 5.55 2.05 3.15 81 5.55 1.45 3.35 5.50 1.40 3.30 5.55 2.85 3.35 82 5.20 1.25 2.90 5.15 1.25 2.90 5.20 2.50 2.90 83 4.90 0.95 3.10 4.90 0.95 2.90 4.90 1.90 3.10 84 5.25 1.10 3.25 5.25 1.10 3.25 5.25 2.20 3.25 85 6.40 1.05 2.90 6.40 1.05 2.90 6.40 2.10 2.90 86 6.20 1.10 3.10 6.20 1.10 3.10 6.20 2.20 3.10 87 6.70 1.10 3.40 6.70 1.00 3.40 6.70 2.10 3.40 88 6.60 1.20 3.40 6.50 1.15 3.30 6.60 2.35 3.40 89 5.00 1.40 3.05 4.95 1.35 3.00 5.00 2.75 3.05 90 5.00 1.45 2.75 5.05 1.50 2.95 5.05 2.95 2.95 91 6.70 0.95 3.00 6.80 0.95 2.90 6.80 1.90 3.00 92 4.95 1.05 3.25 5.00 1.10 3.35 5.00 2.15 3.35 93 5.05 1.05 2.95 4.70 1.05 2.90 5.05 2.10 2.95 94 5.05 1.10 3.10 5.05 1.10 3.10 5.05 2.20 3.10 95 5.10 1.50 3.20 5.15 1.55 3.25 5.15 3.05 3.25 96 6.20 1.20 3.90 6.15 1.15 3.85 6.20 2.35 3.90 97 6.30 1.00 3.50 6.35 1.05 3.55 6.35 2.05 3.55 98 6.05 1.10 3.10 6.00 1.05 3.05 6.05 2.15 3.10 99 5.60 0.95 2.80 5.60 1.00 2.75 5.60 1.95 2.80 100 5.90 1.35 3.15 5.95 1.30 3.15 5.95 2.65 3.15 Table A-9. Mussel Thickness M easurement in cm (5/22/05) Mussel 1Top 2Top 3Top 4Top 5Top 1Bottom 2Bottom 3Bottom 4Bottom 5Bottom 1 0.114 0.079 0.244 0.1500. 1270.1040.1070.211 0.102 0.112 2 0.094 0.124 0.229 0.1140. 1190.0660.1070.231 0.104 0.114 3 0.097 0.109 0.264 0.1300. 1370.0890.1350.284 0.132 0.124 4 0.117 0.124 0.358 0.0860. 0990.1090.1470.221 0.117 0.104 5 0.071 0.094 0.262 0.1270. 1300.1090.1240.236 0.127 0.127 6 0.091 0.109 0.267 0.1300. 1240.0790.1070.254 0.124 0.127 7 0.140 0.109 0.165 0.0810. 0940.1040.1320.170 0.112 0.122 8 0.084 0.132 0.221 0.1240. 1300.0970.1270.244 0.124 0.119 9 0.064 0.094 0.193 0.1020.109 0.0740.0990.201 0.104 0.099

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99 Table A-9 Continued Mussel 1Top 2Top 3Top 4Top 5Top 1Bottom 2Bottom 3Bottom 4Bottom 5Bottom 10 0.089 0.114 2.591 0.0790. 0910.1040.1092.921 0.107 0.099 11 0.104 0.130 0.231 0.1070. 1090.0990.1300.241 0.081 0.081 12 0.109 0.147 0.221 0.1170. 1040.1040.1070.211 0.102 0.112 13 0.107 0.104 0.241 0.1300. 1190.1220.1120.236 0.130 0.130 14 0.079 0.130 0.211 0.1220. 1120.0990.1040.206 0.130 0.132 15 0.079 0.107 0.206 0.0970. 0890.1350.1090.216 0.119 0.109 16 0.089 0.117 0.165 0.1190. 1300.0990.1170.160 0.127 0.124 17 0.102 0.104 0.241 0.1300. 1240.1040.1240.236 0.112 0.130 18 0.104 0.089 0.267 0.1070. 1120.1040.1092.692 0.107 0.099 19 0.109 0.147 0.221 0.1170. 1040.1090.1170.231 0.117 0.114 20 0.094 0.117 0.218 0.1020. 1320.1190.1140.208 0.104 0.127 21 0.079 0.124 0.196 0.0690. 0790.0910.1270.206 0.084 0.089 22 0.064 0.109 0.229 0.1140. 1190.0660.1090.234 0.130 0.122 23 0.089 0.132 0.231 0.1020. 1190.0940.1370.221 0.112 0.122 24 0.071 0.102 0.165 0.0660. 0760.0790.1070.170 0.079 0.107 25 0.074 0.109 0.218 0.1140. 1190.0840.1170.213 0.122 0.102 26 0.074 0.097 0.201 0.1190. 1350.0860.1040.193 0.127 0.137 27 0.097 0.109 0.264 0.1300. 1370.0890.1350.284 0.132 0.124 28 0.130 0.145 0.180 0.0740. 0940.1190.1300.079 0.104 0.114 29 0.071 0.094 0.193 0.1040. 0990.0740.1070.180 0.109 0.099 30 0.079 0.107 0.165 0.0990. 0940.0790.1070.257 0.107 0.117 31 0.079 0.130 0.231 0.1070. 1090.0840.1190.254 0.104 0.117 32 0.104 0.150 0.203 0.0810. 1300.0740.1300.246 0.099 0.094 33 0.064 0.114 0.231 0.1170. 1090.0970.1120.241 0.124 0.127 34 0.089 0.130 0.221 0.1300. 0910.0740.1040.211 0.104 0.117 35 0.104 0.147 0.241 0.1220. 1090.1040.1090.236 0.107 0.097 36 0.079 0.107 0.254 0.1240. 1270.0810.1090.259 0.127 0.127 37 0.104 0.132 0.170 0.1120. 1220.0990.1370.251 0.112 0.130 38 0.097 0.127 0.244 0.1240. 1190.1020.1240.277 0.109 0.124 39 0.089 0.114 2.591 0.0790. 0910.0940.1172.565 0.089 0.097 40 0.104 0.130 0.231 0.1070. 1090.1020.1240.257 0.114 0.117 41 0.117 0.124 0.358 0.0860. 0990.1090.1470.246 0.117 0.104 42 0.079 0.112 0.229 0.1140. 1220.0790.0910.206 0.104 0.107 43 0.089 0.104 0.241 0.1300. 1190.1140.1090.236 0.097 0.099 44 0.071 0.109 0.218 0.1140. 1190.0840.1170.213 0.124 0.102 45 0.104 0.109 2.667 0.1070. 0990.1020.1122.565 0.102 0.104 46 0.099 0.130 0.241 0.0810. 0810.1020.1320.254 0.084 0.099 47 0.117 0.081 0.107 0.1300. 1300.1190.1090.206 0.104 0.097 48 0.079 0.130 0.231 0.1070. 1090.0840.1190.254 0.104 0.117 49 0.064 0.094 0.193 0.1020. 1090.0740.0990.201 0.104 0.114 50 0.097 0.112 0.241 0.1240. 1270.0790.1020.254 0.114 0.124 51 0.102 0.130 0.279 0.0890. 1040.0990.1190.259 0.102 0.089 52 0.099 0.130 0.241 0.0810. 0810.1020.1240.251 0.099 0.104 53 0.104 0.107 0.211 0.1020. 1120.0940.0970.231 0.109 0.109 54 0.091 0.102 0.249 0.1070. 1300.0970.1300.244 0.124 0.119 55 0.079 0.155 0.279 0.1040. 1140.1120.1550.277 0.097 0.104 56 0.107 0.150 0.254 0.0890. 1020.1140.1450.292 0.107 0.117 57 0.096 0.109 0.264 0.1300. 1370.1020.1040.234 0.127 0.119 58 0.105 0.117 0.257 0.1240. 1270.1300.1320.254 0.104 0.132 59 0.097 0.112 0.241 0.1240.127 0.1020.1240.257 0.114 0.117

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100 Table A-9 Continued Mussel 1Top 2Top 3Top 4Top 5Top 1Bottom 2Bottom 3Bottom 4Bottom 5Bottom 60 0.074 0.104 0.211 0.1040. 1170.1090.1470.246 0.117 0.104 61 0.236 0.086 0.241 0.1170. 1040.0690.1020.231 0.099 0.112 62 0.107 0.132 0.221 0.1470. 1170.1090.1370.218 0.127 0.122 63 0.084 0.104 0.203 0.1240. 0970.1070.0890.201 0.099 0.109 64 0.079 0.094 0.231 0.1170. 1090.0790.1090.208 0.107 0.124 65 0.099 0.112 0.203 0.1020. 1300.0840.1370.206 0.104 0.114 66 0.102 0.130 0.231 0.0690. 1090.0860.1070.234 0.099 0.099 67 0.102 0.132 0.254 0.1140. 0910.0890.1170.221 0.124 0.117 68 0.094 0.104 0.198 0.0940. 1300.1240.1240.173 0.119 0.097 69 0.091 0.102 0.221 0.1400. 1420.1040.1220.130 0.086 0.107 70 0.087 0.104 0.218 0.1270. 1370.1040.1300.231 0.107 0.109 71 0.071 0.107 0.244 0.0790. 0890.0740.1070.236 0.109 0.084 72 0.102 0.124 0.251 0.0990. 1040.0990.1300.241 0.081 0.081 73 0.114 0.109 0.163 0.1320. 1300.1090.1240.160 0.124 0.135 74 0.089 0.097 0.262 0.1270. 1220.0910.1070.257 0.127 0.127 75 0.069 0.094 0.218 0.0860. 0840.0710.1040.089 0.097 0.107 76 0.094 0.097 0.231 0.1090. 1090.1040.0890.267 0.107 0.112 77 0.140 0.109 0.165 0.0810. 0940.1040.1320.170 0.102 0.099 78 0.066 0.107 0.231 0.1040. 1140.0910.1090.267 0.130 0.124 79 0.097 0.119 0.249 0.1170. 0990.1070.1270.244 0.112 0.122 80 0.124 0.124 0.173 0.1190. 0970.0740.1300.246 0.099 0.094 81 0.079 0.155 0.279 0.1040. 1140.0970.1120.241 0.124 0.127 82 0.107 0.150 0.254 0.0890. 1020.0860.1040.218 0.127 0.137 83 0.089 0.114 0.218 0.1190. 0990.1070.0790.213 0.097 0.104 84 0.107 0.104 0.241 0.1040. 0890.1020.0940.272 0.081 0.107 85 0.102 0.127 0.244 0.1300. 1190.1220.1120.236 0.130 0.130 86 0.086 0.114 0.180 0.0860. 1120.0660.1370.257 0.081 0.084 87 0.089 0.130 0.193 0.1270. 0890.0940.1070.218 0.124 0.124 88 0.119 0.107 0.165 0.1300. 1300.0790.1170.201 0.127 0.124 89 0.074 0.124 0.231 0.0810. 1240.0840.1040.208 0.094 0.102 90 0.091 0.102 0.221 0.1400. 1420.1040.1220.130 0.086 0.107 91 0.079 0.130 0.231 0.1070. 1090.0840.1190.254 0.104 0.117 92 0.109 0.081 0.262 0.1040. 1140.0860.1300.254 0.122 0.102 93 0.119 0.130 0.218 0.1300. 1020.0710.1070.170 0.127 0.137 94 0.091 0.094 0.231 0.0860. 0990.1020.1120.244 0.132 0.124 95 0.084 0.119 0.254 0.1040. 1170.0790.1550.279 0.104 0.114 96 0.086 0.107 0.234 0.0990. 0990.1140.1090.163 0.132 0.130 97 0.089 0.117 0.221 0.1240. 1170.0890.0970.262 0.127 0.122 98 0.097 0.102 0.241 0.0910. 0970.1040.0890.267 0.107 0.112 99 0.102 0.124 0.257 0.1140. 1170.1040.1500.231 0.081 0.130 100 0.107 0.150 0.254 0.0890.102 0.1140.1450.292 0.107 0.117 Oyster Irradiation Dose Measurements Table A-10. Electron Beam i rradiated oysters in kGy Oysters External Top Internal External Bottom Internal/Top 1 4.3 4.0 4.3 0.93 2 4.2 4.3 4.1 1.02 3 2.8 1.9 1.6 0.68 4 2.3 1.6 1.4 0.70

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101 Table A-10 Continued Oysters External Top Internal External Bottom Internal/Top 5 3.8 3.2 3.0 0.84 6 3.0 2.8 2.7 0.93 7 3.1 2.3 2.5 0.74 8 2.2 1.9 2.0 0.86 9 2.6 1.8 2.5 0.69 10 3.6 2.4 2.1 0.67 11 2.9 2.1 2.4 0.72 12 5.4 2.5 4.8 0.46 13 5.0 4.1 4.3 0.82 14 2.8 2.3 2.7 0.82 15 4.3 2.3 2.3 0.53 16 4.9 4.6 4.3 0.94 17 2.8 2.1 2.5 0.75 18 5.2 5.0 4.9 0.96 19 6.7 4.9 5.5 0.73 20 4.2 4.0 3.7 0.95 21 1.7 2.0 1.6 1.18 22 1.8 2.0 1.8 1.11 23 2.1 1.8 1.4 0.86 24 2.0 2.0 2.0 1.00 25 2.3 2.2 2.1 0.96 26 4.4 3.9 4.3 0.89 27 4.3 3.0 3.6 0.70 28 4.1 4.2 3.9 1.02 29 3.9 3.8 3.7 0.97 30 4.1 3.7 4.1 0.90 31 5.1 2.2 3.1 0.43 32 5.0 5.0 4.4 1.00 33 2.1 2.1 2.1 1.00 34 2.0 2.1 1.9 1.05 35 4.9 4.6 3.9 0.94 36 2.2 1.7 1.7 0.77 37 4.9 4.0 3.7 0.82 38 2.6 2.1 2.1 0.81 39 4.4 4.4 4.4 1.00 40 4.2 4.0 4.2 0.95 41 5.0 4.4 3.6 0.88 42 6.0 3.7 3.1 0.62 43 2.1 1.9 1.6 0.90 44 3.3 1.8 1.9 0.55 45 1.7 1.6 1.5 0.94 46 1.9 1.4 1.7 0.74 47 2.0 1.6 1.9 0.80 48 1.8 1.5 1.8 0.83 49 3.1 1.5 2.2 0.48 50 4.1 2.2 2.1 0.54 51 2.9 2.8 2.5 0.97 52 5.3 5.0 4.5 0.94 53 3.1 3.0 3.1 0.97 54 3.2 2.9 3.2 0.91 55 5.3 5.3 5.1 1.00

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102 Table A-10 Continued Oysters External Top Internal External Bottom Internal/Top 56 4.0 3.7 4.0 0.93 57 4.5 4.3 4.0 0.96 58 4.6 4.2 3.1 0.91 59 6.1 4.4 4.4 0.72 60 2.0 1.8 1.7 0.90 61 2.3 2.1 1.5 0.91 62 2.3 1.8 2.0 0.78 63 3.9 3.9 3.7 1.00 64 4.4 4.4 3.7 1.00 65 3.7 3.7 3.1 1.00 66 2.5 1.4 2.2 0.56 67 1.9 2.5 1.9 1.32 68 2.5 1.9 1.5 0.76 69 3.8 3.2 3.8 0.84 70 2.3 2.1 2.3 0.91 71 4.5 4.1 4.0 0.91 72 4.2 4.5 3.9 1.07 73 4.5 4.0 4.2 0.89 74 4.4 4.0 4.0 0.91 75 2.9 1.8 1.9 0.62 76 4.5 4.4 3.8 0.98 77 2.1 2.0 1.9 0.95 78 2.6 2.6 2.5 1.00 79 2.0 1.9 1.9 0.95 80 4.5 3.3 3.9 0.73 81 3.9 3.7 3.3 0.95 82 4.2 3.9 3.0 0.93 83 4.2 3.7 3.9 0.88 84 3.9 4.0 3.2 1.03 85 5.6 5.0 4.6 0.89 86 4.9 3.8 3.9 0.78 87 2.5 2.2 2.3 0.88 88 2.2 2.3 2.1 1.05 89 2.4 1.5 2.0 0.63 90 3.7 3.7 3.6 1.00 91 3.9 4.6 3.7 1.18 92 3.8 3.7 3.7 0.97 93 1.6 1.4 1.5 0.88 94 2.2 1.6 2.0 0.73 95 4.8 4.0 4.1 0.83 96 4.0 4.2 3.7 1.05 97 4.3 3.6 3.7 0.84 98 3.7 2.4 3.0 0.65 99 2.3 2.0 2.3 0.87 100 1.8 2.0 1.6 1.11 Table A-11. X-ray Irradiated Oysters in kGy Oysters External Top Internal External Bottom Internal/Top 1 3.7 4.2 3.4 1.14 2 4.2 4.1 4.1 0.98 3 2.0 1.4 1.9 0.70

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103 Table A-11 Continued Oysters External Top Internal External Bottom Internal/Top 4 1.8 1.5 1.8 0.83 5 5.1 5.6 5.1 1.10 6 4.9 3.7 3.9 0.76 7 3.1 2.3 2.5 0.74 8 1.9 1.4 1.6 0.74 9 1.5 1.7 1.3 1.13 10 1.7 1.2 1.5 0.71 11 1.8 1.6 1.5 0.89 12 4.1 4.3 3.6 1.05 13 3.8 3.6 3.7 0.95 14 1.6 1.8 1.5 1.13 15 4.3 2.3 2.3 0.53 16 4.4 4.2 4.2 0.95 17 2.2 1.5 1.5 0.68 18 4.6 3.6 3.7 0.78 19 4.2 3.8 3.8 0.90 20 6.9 5.1 5.0 0.74 21 1.5 1.7 1.5 1.13 22 1.9 1.6 1.8 0.84 23 2.1 1.8 1.4 0.86 24 1.9 1.8 1.8 0.95 25 3.0 1.5 1.4 0.50 26 4.1 4.0 3.6 0.98 27 4.8 4.2 3.8 0.88 28 3.8 3.8 3.6 1.00 29 5.0 6.5 3.7 1.30 30 4.9 4.8 4.6 0.98 31 4.1 3.7 4.1 0.90 32 4.2 4.0 4.0 0.95 33 1.3 1.2 1.3 0.92 34 2.8 1.5 1.5 0.54 35 3.7 3.4 3.7 0.92 36 1.9 1.5 1.2 0.79 37 4.4 4.0 3.9 0.91 38 2.6 2.1 2.1 0.81 39 6.0 6.9 5.2 1.15 40 4.0 3.4 4.0 0.85 41 4.3 3.7 4.2 0.86 42 6.3 5.6 5.7 0.89 43 2.0 1.3 2.0 0.65 44 1.7 2.4 1.5 1.41 45 1.7 1.7 1.5 1.00 46 2.0 1.6 1.9 0.80 47 1.5 1.4 1.5 0.93 48 2.0 2.4 1.4 1.20 49 2.5 1.5 1.8 0.60 50 1.5 1.4 1.3 0.93 51 1.7 1.5 1.5 0.88 52 4.2 4.5 4.1 1.07 53 1.6 1.3 1.2 0.81 54 1.8 1.7 1.7 0.94

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104 Table A-11 Continued Oysters External Top Internal External Bottom Internal/Top 55 4.3 4.0 4.3 0.93 56 4.8 4.1 4.6 0.85 57 4.5 3.8 3.7 0.84 58 5.1 6.4 5.0 1.25 59 4.8 3.4 3.4 0.71 60 2.3 1.2 1.5 0.52 61 1.4 1.2 1.3 0.86 62 1.6 1.6 1.3 1.00 63 4.1 4.1 3.6 1.00 64 3.8 4.0 3.2 1.05 65 4.9 3.9 3.8 0.80 66 2.1 1.5 1.5 0.71 67 1.5 1.2 1.4 0.80 68 2.5 1.9 1.5 0.76 69 4.6 4.8 4.4 1.04 70 2.2 1.4 2.0 0.64 71 3.6 3.4 3.2 0.94 72 4.1 3.4 3.9 0.83 73 4.1 4.0 4.0 0.98 74 5.2 4.1 4.0 0.79 75 1.5 1.5 1.4 1.00 76 4.2 3.7 4.0 0.88 77 2.1 2.0 1.9 0.95 78 2.6 2.6 2.5 1.00 79 3.7 4.0 3.6 1.08 80 4.3 3.8 3.8 0.88 81 3.3 3.6 3.1 1.09 82 4.5 4.5 4.4 1.00 83 4.4 4.8 3.4 1.09 84 3.9 3.4 3.3 0.87 85 5.6 5.5 5.5 0.98 86 4.1 3.8 4.0 0.93 87 2.5 2.2 2.3 0.88 88 1.8 1.3 1.6 0.72 89 1.5 2.6 1.5 1.73 90 4.0 3.6 3.6 0.90 91 3.7 3.7 3.6 1.00 92 3.8 3.7 3.4 0.97 93 2.2 1.5 2.0 0.68 94 1.8 2.2 1.2 1.22 95 6.4 4.3 3.7 0.67 96 3.7 3.2 3.6 0.86 97 3.4 3.4 3.4 1.00 98 1.6 1.4 1.4 0.88 99 1.8 1.5 1.4 0.83 100 1.6 1.9 1.5 1.19 Table A-12. Gamma Ray Irradiated Oysters in kGy Oysters External Top Internal External Bottom Internal/Top 1 3.9 3.8 3.7 0.97 2 4.3 4.3 4.2 1.00

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105 Table A-12 Continued Oysters External Top Internal External Bottom Internal/Top 3 1.6 1.3 1.5 0.81 4 1.5 1.4 1.4 0.93 5 4.5 4.1 3.9 0.91 6 3.7 3.7 3.4 1.00 7 3.1 3.0 2.9 0.97 8 2.0 1.6 1.6 0.80 9 2.7 2.3 2.1 0.85 10 2.2 1.8 1.7 0.82 11 1.7 1.6 1.3 0.94 12 5.0 4.6 4.6 0.92 13 4.0 3.8 3.7 0.95 14 1.8 1.5 1.4 0.83 15 3.3 2.8 2.5 0.85 16 4.3 4.2 3.9 0.98 17 3.1 2.3 2.1 0.74 18 4.9 4.6 4.5 0.94 19 4.4 4.0 4.0 0.91 20 3.9 3.7 3.7 0.95 21 2.0 1.8 1.7 0.90 22 1.9 1.8 1.7 0.95 23 3.1 2.7 2.7 0.87 24 1.8 1.6 1.4 0.89 25 2.3 2.0 1.8 0.87 26 3.8 3.7 3.7 0.97 27 4.5 4.4 4.4 0.98 28 4.4 4.2 4.1 0.95 29 4.0 3.9 3.8 0.98 30 4.1 3.9 3.8 0.95 31 2.9 2.8 2.8 0.97 32 3.9 3.9 3.8 1.00 33 2.1 1.8 1.8 0.86 34 2.0 2.0 2.0 1.00 35 4.6 4.1 4.0 0.89 36 2.4 1.9 1.7 0.79 37 3.9 3.8 3.3 0.97 38 3.1 2.9 2.8 0.94 39 3.8 3.7 3.4 0.97 40 4.0 3.8 3.4 0.95 41 3.7 3.6 3.4 0.97 42 4.2 3.9 3.7 0.93 43 2.1 2.1 2.0 1.00 44 2.0 1.8 1.7 0.90 45 2.0 2.0 1.8 1.00 46 4.4 4.4 3.4 1.00 47 2.1 1.9 1.7 0.90 48 2.0 1.5 1.5 0.75 49 2.2 2.0 2.0 0.91 50 2.2 2.1 1.9 0.95 51 1.8 1.8 1.7 1.00 52 4.5 4.5 4.2 1.00 53 2.5 2.2 2.1 0.88

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106 Table A-12 Continued Oysters External Top Internal External Bottom Internal/Top 54 2.0 1.9 1.8 0.95 55 4.6 4.2 4.1 0.91 56 4.6 4.4 4.4 0.96 57 4.4 4.3 4.2 0.98 58 4.0 3.9 3.7 0.98 59 4.6 4.5 4.0 0.98 60 1.9 1.8 1.6 0.95 61 1.8 1.8 1.8 1.00 62 1.4 1.2 1.3 0.86 63 4.0 3.9 3.7 0.98 64 4.4 4.3 4.2 0.98 65 4.3 3.8 3.8 0.88 66 2.3 1.9 1.9 0.83 67 1.3 1.2 1.2 0.92 68 4.2 4.1 3.9 0.98 69 5.1 4.9 4.9 0.96 70 1.3 1.2 1.2 0.92 71 5.1 4.9 4.9 0.96 72 5.0 4.6 4.9 0.92 73 4.2 4.2 4.1 1.00 74 4.8 4.2 4.2 0.88 75 2.5 2.1 1.9 0.84 76 4.0 3.8 3.6 0.95 77 3.3 2.9 2.7 0.88 78 2.8 2.8 2.7 1.00 79 4.2 4.2 4.1 1.00 80 3.8 3.7 3.7 0.97 81 5.5 5.2 5.1 0.95 82 3.8 3.7 3.7 0.97 83 4.6 4.6 4.5 1.00 84 4.8 4.6 4.6 0.96 85 3.8 3.8 3.7 1.00 86 4.9 4.6 4.5 0.94 87 3.2 2.8 2.8 0.88 88 1.8 1.6 1.5 0.89 89 1.8 1.7 1.6 0.94 90 4.6 4.6 4.3 1.00 91 4.8 4.6 4.0 0.96 92 4.4 4.1 4.0 0.93 93 2.3 2.1 2.0 0.91 94 2.0 1.7 1.5 0.85 95 4.1 3.9 3.7 0.95 96 3.9 3.8 3.7 0.97 97 4.3 4.2 4.1 0.98 98 1.3 1.3 1.2 1.00 99 1.8 1.8 1.7 1.00 100 1.5 1.5 1.3 1.00

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107 Clam Irradiated Dose Measurements Table A-13. Electron Beam Irradiated Clams in kGy Clams External Top Internal External Bottom Internal/Top 1 4.1 3.9 3.4 0.95 2 4.1 3.9 3.2 0.95 3 2.7 1.8 1.5 0.67 4 2.6 1.6 1.5 0.62 5 3.9 3.8 3.9 0.97 6 3.2 1.6 2.6 0.50 7 3.9 3.3 3.8 0.85 8 3.4 3.7 3.3 1.09 9 4.1 3.9 3.4 0.95 10 3.8 3.7 3.6 0.97 11 2.4 1.7 1.6 0.71 12 3.9 3.8 3.2 0.97 13 2.4 1.8 2.3 0.75 14 3.8 3.8 3.8 1.00 15 3.2 3.7 3.2 1.16 16 2.3 1.7 1.7 0.74 17 3.4 3.7 3.2 1.09 18 3.8 2.2 3.6 0.58 19 3.8 3.4 1.5 0.89 20 3.9 3.7 3.6 0.95 21 2.0 1.9 2 0.95 22 3.6 3.6 3.6 1.00 23 1.8 1.5 1.8 0.83 24 2.9 1.7 2.1 0.59 25 4.5 3.7 3.6 0.82 26 3.7 3.4 3.2 0.92 27 4.1 4.2 3.9 1.02 28 3.8 3.8 3.3 1.00 29 4.0 3.8 3.4 0.95 30 1.8 1.8 1.7 1.00 31 2.1 1.8 1.9 0.86 32 2.2 1.9 1.7 0.86 33 4.6 3.8 4.5 0.83 34 3.4 3.7 3.4 1.09 35 3.8 4.1 3.6 1.08 36 1.9 1.2 1.8 0.63 37 1.7 1.9 1.6 1.12 38 3.3 3.7 3.2 1.12 39 4.3 3.7 4 0.86 40 1.7 1.7 1.5 1.00 41 4.0 4.1 2.9 1.03 42 1.7 1.8 1.5 1.06 43 3.6 3.4 3.4 0.94 44 3.8 3.7 3.6 0.97 45 2.8 1.7 2.3 0.61 46 3.6 3.7 3.3 1.03 47 3.4 3.6 3.3 1.06 48 1.8 1.7 1.7 0.94 49 2.5 2.0 2 0.80

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108 Table A-13. Continued Clams External Top Internal External Bottom Internal/Top 50 1.8 1.7 1.7 0.94 51 2.4 1.5 2 0.63 52 2.2 1.8 1.8 0.82 53 2.3 1.7 1.8 0.74 54 1.8 1.7 1.3 0.94 55 3.8 3.6 3.6 0.95 56 4.5 3.3 3.8 0.73 57 1.8 1.7 1.8 0.94 58 3.9 3.2 3.6 0.82 59 2.0 1.8 1.9 0.90 60 4.1 3.4 2 0.83 61 3.8 4.0 3.2 1.05 62 4.0 3.7 2.6 0.93 63 3.7 4.0 3.4 1.08 64 3.6 3.8 3.3 1.06 65 1.7 1.5 1.6 0.88 66 2.3 1.4 1.6 0.61 67 3.8 3.8 3.4 1.00 68 2.4 1.5 1.6 0.63 69 2.3 1.9 1.9 0.83 70 3.8 3.6 3.4 0.95 71 2.2 1.6 1.6 0.73 72 4.1 4.1 3.9 1.00 73 4.2 3.1 3.7 0.74 74 2.0 1.4 1.3 0.70 75 2.1 1.5 1.4 0.71 76 1.8 1.7 1.7 0.94 77 1.7 1.8 1.6 1.06 78 3.1 1.7 1.6 0.55 79 4.2 3.2 2.9 0.76 80 2.1 1.6 1.7 0.76 81 3.7 3.7 3.2 1.00 82 3.9 2.9 3.9 0.74 83 1.9 1.7 1.8 0.89 84 3.8 3.8 3.8 1.00 85 2.3 1.9 2.1 0.83 86 1.9 1.8 1.8 0.95 87 3.8 3.4 3.4 0.89 88 4.0 3.9 3.8 0.98 89 1.6 2.0 1.3 1.25 90 2.6 1.4 1.7 0.54 91 4.5 4.0 3.7 0.89 92 4.5 3.2 3.8 0.71 93 1.8 1.7 1.6 0.94 94 1.5 1.4 1.5 0.93 95 2.7 1.9 1.8 0.70 96 2.3 1.7 1.8 0.74 97 2.3 2.0 1.7 0.87 98 2.3 1.7 1.6 0.74 99 3.7 3.6 3.3 0.97 100 2.1 1.3 2.1 0.62

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109 Table A-14. X-ray Irradiated Clams in kGy Clams External Top Internal External Bottom Internal/Top 1 4.3 4.3 3.1 1.00 2 4.0 4.0 2.9 1.00 3 2.7 1.8 1.5 0.67 4 2.6 2.0 2.4 0.77 5 4.2 4.9 3.8 1.17 6 4.3 4.3 4.0 1.00 7 4.4 3.8 3.8 0.86 8 4.0 3.8 4.0 0.95 9 4.4 3.7 3.8 0.84 10 6.3 4.4 6.0 0.70 11 2.4 2.4 2.2 1.00 12 4.5 5.1 4.4 1.13 13 1.7 1.7 1.6 1.00 14 4.2 4.0 4.1 0.95 15 4.1 3.9 3.7 0.95 16 2.5 2.1 2.4 0.84 17 5.4 5.4 4.9 1.00 18 4.0 4.0 3.9 1.00 19 4.3 4.2 4.2 0.98 20 3.8 3.7 3.7 0.97 21 1.5 1.7 1.5 1.13 22 4.0 4.2 4.0 1.05 23 2.4 2.3 2.3 0.96 24 3.1 2.4 2.1 0.77 25 4.0 3.9 3.8 0.98 26 3.8 3.8 3.8 1.00 27 4.9 4.5 3.8 0.92 28 4.2 3.8 3.9 0.90 29 4.3 4.0 4.1 0.93 30 1.9 1.6 1.6 0.84 31 3.9 2.7 2.5 0.69 32 1.7 1.4 1.6 0.82 33 4.5 4.2 4.2 0.93 34 4.9 4.1 4.4 0.84 35 4.2 3.9 4.0 0.93 36 2.3 1.8 1.9 0.78 37 1.6 1.6 1.3 1.00 38 4.2 4.2 3.8 1.00 39 3.9 4.0 3.3 1.03 40 2.4 2.2 2.2 0.92 41 5.0 4.5 4.6 0.90 42 1.4 1.6 1.2 1.14 43 4.8 4.4 3.9 0.92 44 4.6 3.8 4.0 0.83 45 1.7 1.8 1.5 1.06 46 5.1 4.2 4.2 0.82 47 4.6 4.8 4.0 1.04 48 2.5 3.0 1.7 1.20 49 2.1 1.6 1.7 0.76 50 4.2 2.4 2.4 0.57 51 2.1 2.1 2.1 1.00

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110 Table A-14 Continued Clams External Top Internal External Bottom Internal/Top 52 2.1 1.4 2.1 0.67 53 3.4 2.3 2.4 0.68 54 2.7 1.5 2.0 0.56 55 4.0 4.6 3.9 1.15 56 4.2 3.9 4.2 0.93 57 2.4 2.2 2.1 0.92 58 4.5 3.9 4.0 0.87 59 1.6 1.5 1.5 0.94 60 4.4 4.2 3.9 0.95 61 4.0 4.0 3.8 1.00 62 4.3 4.3 4.2 1.00 63 4.2 4.3 3.6 1.02 64 3.7 3.8 3.6 1.03 65 2.2 1.8 2.1 0.82 66 2.5 1.9 2.2 0.76 67 4.8 4.1 3.8 0.85 68 2.4 2.2 2.3 0.92 69 1.6 1.9 1.6 1.19 70 3.8 3.8 3.7 1.00 71 1.6 2.6 1.6 1.63 72 4.5 4.5 4.4 1.00 73 3.8 3.9 2.6 1.03 74 1.7 1.6 1.6 0.94 75 1.7 1.6 1.4 0.94 76 1.7 2.1 1.6 1.24 77 2.3 2.4 1.4 1.04 78 2.9 2.4 2.6 0.83 79 4.3 3.9 4.0 0.91 80 1.6 1.5 1.5 0.94 81 5.2 5.3 4.6 1.02 82 4.5 4.1 4.3 0.91 83 3.1 2.5 2.4 0.81 84 4.8 4.3 4.4 0.90 85 1.7 1.5 1.4 0.88 86 1.7 1.5 1.3 0.88 87 4.8 4.0 3.3 0.83 88 4.8 4.2 4.8 0.88 89 1.9 1.5 1.4 0.79 90 3.1 1.8 3.1 0.58 91 4.5 3.9 3.9 0.87 92 4.3 4.2 4.2 0.98 93 2.0 1.9 1.6 0.95 94 2.3 2.3 2.1 1.00 95 1.9 1.3 1.3 0.68 96 1.2 1.2 1.2 1.00 97 1.7 1.9 1.7 1.12 98 2.3 2.3 1.9 1.00 99 4.4 3.9 3.6 0.89 100 2.3 2.1 2.2 0.91

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111 Table A-15. Gamma Ray Irradiated Clams in kGy Clams External Top Internal External Bottom Internal/Top 1 4.8 4.2 4.0 0.88 2 4.4 4.4 4.0 1.00 3 3.3 3.1 2.9 0.94 4 1.6 1.5 1.2 0.94 5 4.5 4.3 4.3 0.96 6 4.5 4.5 4.3 1.00 7 4.9 4.4 4.4 0.90 8 5.1 5.1 4.9 1.00 9 5.0 4.2 4.2 0.84 10 4.6 4.5 4.4 0.98 11 1.6 1.6 1.3 1.00 12 4.5 4.4 4.4 0.98 13 2.2 2.0 1.9 0.91 14 4.2 4.1 3.9 0.98 15 4.3 3.8 4.3 0.88 16 2.4 1.9 2.2 0.79 17 4.9 4.2 4.1 0.86 18 4.2 4.2 3.7 1.00 19 4.6 4.1 4.0 0.89 20 5.2 4.9 5.1 0.94 21 2.1 1.9 1.9 0.90 22 5.1 4.6 4.5 0.90 23 1.9 1.8 1.3 0.95 24 1.9 1.9 1.8 1.00 25 4.6 4.5 4.0 0.98 26 4.6 4.6 4.4 1.00 27 4.6 4.5 4.3 0.98 28 4.3 4.3 4.1 1.00 29 5.1 4.9 5.1 0.96 30 1.7 1.7 1.5 1.00 31 2.3 2.2 2.1 0.96 32 2.1 1.8 1.4 0.86 33 4.5 4.1 4.0 0.91 34 5.1 5.0 4.6 0.98 35 5.0 4.9 4.8 0.98 36 2.9 2.6 2.6 0.90 37 1.6 1.5 1.5 0.94 38 4.7 4.7 4.3 1.00 39 4.5 3.8 4.4 0.84 40 2.0 1.6 1.4 0.80 41 4.4 4.4 4.2 1.00 42 2.0 1.9 1.9 0.95 43 4.6 4.6 4.5 1.00 44 4.4 4.2 4.0 0.95 45 2.3 2.2 2.2 0.96 46 4.8 4.4 4.1 0.92 47 4.3 4.2 3.8 0.98 48 1.8 1.7 1.7 0.94 49 2.0 2.0 1.9 1.00 50 1.7 1.7 1.6 1.00

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112 Table A-15 Continued Clams External Top Internal External Bottom Internal/Top 51 2.0 1.8 1.2 0.90 52 1.9 1.8 1.8 0.95 53 2.1 2.0 1.8 0.95 54 2.6 2.1 2.1 0.81 55 4.5 4.2 4.0 0.93 56 4.6 4.4 4.2 0.96 57 2.0 1.7 1.6 0.85 58 4.9 4.8 4.5 0.98 59 2.4 2.3 1.9 0.96 60 4.1 4.0 3.9 0.98 61 4.5 4.2 4.2 0.93 62 4.4 4.3 4.2 0.98 63 4.6 4.6 4.4 1.00 64 4.8 4.0 3.9 0.83 65 2.1 2.1 1.5 1.00 66 1.5 1.4 1.3 0.93 67 4.2 4.2 4.1 1.00 68 2.0 1.7 1.2 0.85 69 2.3 1.5 1.2 0.65 70 4.6 4.5 4.4 0.98 71 2.1 2.0 2.0 0.95 72 4.8 4.4 3.7 0.92 73 5.0 4.3 4.3 0.86 74 1.8 1.8 1.5 1.00 75 2.1 1.7 1.4 0.81 76 2.1 2.0 1.8 0.95 77 2.4 1.8 1.6 0.75 78 1.9 1.8 1.7 0.95 79 4.1 4.1 3.9 1.00 80 2.6 2.3 2.1 0.88 81 4.6 4.6 3.8 1.00 82 4.8 4.5 4.3 0.94 83 3.3 2.0 1.6 0.61 84 4.6 4.6 4.6 1.00 85 1.7 1.9 1.5 1.12 86 1.7 1.7 1.5 1.00 87 4.3 4.2 4.2 0.98 88 4.3 4.1 4.2 0.95 89 1.8 1.5 1.2 0.83 90 2.3 2.0 1.9 0.87 91 4.4 4.3 4.2 0.98 92 4.5 4.4 4.2 0.98 93 1.7 1.5 1.4 0.88 94 1.8 1.7 1.6 0.94 95 2.3 2.2 2.2 0.96 96 2.3 2.3 2.1 1.00 97 1.5 1.5 1.3 1.00 98 2.4 2.0 1.9 0.83 99 4.4 4.0 4.0 0.91 100 1.8 1.5 1.4 0.83

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113 Mussel Irradiation Dose Measurements Table A-16. Electron Beam irradiated mussels in kGy Mussels External Top Internal External Bottom Internal/Top 1 2.0 1.6 1.6 0.80 2 3.2 3.2 1.6 1.00 3 2.0 1.4 1.3 0.70 4 1.9 2.1 1.6 1.11 5 3.2 3.0 2.7 0.94 6 1.6 1.5 1.5 0.94 7 3.2 3.1 3.0 0.97 8 3.3 3.2 3.0 0.97 9 1.6 1.6 1.6 1.00 10 3.7 3.4 3.1 0.92 11 1.6 1.2 1.5 0.75 12 3.2 3.3 3.2 1.03 13 2.2 1.4 1.3 0.64 14 3.8 2.9 3.2 0.76 15 1.7 1.3 1.3 0.76 16 3.0 1.3 1.2 0.43 17 1.3 1.6 1.2 1.23 18 3.0 2.7 2.9 0.90 19 1.8 1.5 1.6 0.83 20 1.4 1.3 1.2 0.93 21 1.5 1.5 1.2 1.00 22 3.2 3.1 2.9 0.97 23 1.4 1.8 1.4 1.29 24 1.6 1.6 1.4 1.00 25 1.9 1.8 1.2 0.95 26 2.7 2.8 2.6 1.04 27 3.2 2.8 2.7 0.88 28 1.6 1.5 1.4 0.94 29 1.6 1.5 1.4 0.94 30 1.6 2.1 1.6 1.31 31 1.4 1.6 1.4 1.14 32 1.7 1.6 1.7 0.94 33 3.4 2.9 2.7 0.85 34 3.2 4.1 2.7 1.28 35 3.4 3.4 2.6 1.00 36 3.3 3.2 3.2 0.97 37 3.4 3.7 2.3 1.09 38 3.2 3.0 3.0 0.94 39 1.7 1.5 1.3 0.88 40 1.4 2.0 1.2 1.43 41 1.6 1.6 1.5 1.00 42 3.2 2.8 2.8 0.88 43 3.0 3.1 3.0 1.03 44 1.6 1.6 1.5 1.00 45 1.7 1.3 1.5 0.76 46 1.3 1.5 1.3 1.15 47 2.9 3.7 2.8 1.28 48 3.3 2.9 3.2 0.88 49 1.5 1.5 1.4 1.00

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114 Table A-16 Continued Mussels External Top Internal External Bottom Internal/Top 50 2.9 2.7 2.7 0.93 51 2.3 1.5 2.1 0.65 52 3.0 3.1 2.9 1.03 53 1.7 1.6 1.7 0.94 54 3.3 3.1 2.8 0.94 55 3.1 3.0 3.1 0.97 56 3.2 3.4 3.1 1.06 57 3.2 3.0 3.1 0.94 58 2.8 3.0 2.5 1.07 59 3.2 3.0 3.1 0.94 60 1.5 1.6 1.2 1.07 61 1.6 1.2 1.3 0.75 62 1.8 1.4 1.5 0.78 63 3.1 2.6 2.5 0.84 64 2.8 2.7 2.8 0.96 65 3.3 3.2 2.9 0.97 66 3.2 3.4 2.5 1.06 67 3.0 2.3 2.6 0.77 68 1.5 1.5 1.4 1.00 69 1.6 1.2 1.6 0.75 70 1.5 1.4 1.2 0.93 71 1.9 1.6 1.5 0.84 72 1.7 1.7 1.7 1.00 73 4.2 3.1 3.3 0.74 74 3.1 3.1 2.9 1.00 75 3.3 3.2 3.2 0.97 76 1.7 1.9 1.7 1.12 77 3.1 2.8 2.9 0.90 78 1.5 1.6 1.3 1.07 79 3.7 3.4 3.0 0.92 80 1.7 2.1 1.6 1.24 81 3.7 1.5 3.0 0.41 82 3.6 3.2 3.3 0.89 83 3.1 2.8 2.8 0.90 84 1.4 1.3 1.3 0.93 85 1.4 1.7 1.4 1.21 86 1.4 1.8 1.3 1.29 87 3.3 3.6 2.6 1.09 88 1.7 1.4 1.4 0.82 89 1.7 1.4 1.2 0.82 90 1.7 1.4 1.4 0.82 91 3.4 3.1 3.1 0.91 92 3.4 3.1 2.5 0.91 93 2.9 3.2 2.4 1.10 94 1.6 1.4 1.3 0.88 95 3.4 3.1 3.1 0.91 96 3.1 3.0 3.1 0.97 97 1.4 2.1 1.4 1.50 98 3.2 3.3 3.2 1.03 99 3.3 3.0 3.3 0.91 100 3.2 3.2 3.2 1.00

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115 Table A-17. X-ray Irradi ated Mussels in kGy Mussels External Top Internal External Bottom Internal/Top 1 1.7 1.6 1.7 0.94 2 3.9 3.8 3.7 0.97 3 2.0 1.6 1.6 0.80 4 1.9 2.0 1.9 1.05 5 4.5 4.1 4.0 0.91 6 1.6 1.9 1.5 1.19 7 3.9 3.8 3.8 0.97 8 4.0 4.2 3.8 1.05 9 2.0 1.7 1.7 0.85 10 5.0 5.0 4.9 1.00 11 2.0 1.9 1.7 0.95 12 4.6 4.5 4.1 0.98 13 1.8 2.2 1.8 1.22 14 4.8 5.0 4.4 1.04 15 1.7 1.9 1.6 1.12 16 4.4 4.3 4.2 0.98 17 1.9 1.7 1.6 0.89 18 4.6 4.9 4.5 1.07 19 1.9 2.2 1.7 1.16 20 1.7 1.6 1.6 0.94 21 1.8 1.9 1.7 1.06 22 4.4 4.3 4.2 0.98 23 1.9 1.6 1.6 0.84 24 1.8 1.8 1.7 1.00 25 1.8 1.8 1.6 1.00 26 4.9 4.6 4.3 0.94 27 4.6 4.6 4.6 1.00 28 1.6 1.6 1.6 1.00 29 1.8 1.8 1.8 1.00 30 1.8 1.7 1.7 0.94 31 1.9 1.9 1.8 1.00 32 1.7 2.0 1.6 1.18 33 4.5 4.6 4.3 1.02 34 3.7 4.0 3.6 1.08 35 3.9 3.8 3.6 0.97 36 4.6 4.6 4.6 1.00 37 4.6 4.4 4.5 0.96 38 4.4 4.4 4.3 1.00 39 1.9 2.1 1.8 1.11 40 1.7 1.7 1.7 1.00 41 1.8 1.6 1.6 0.89 42 4.3 4.3 4.2 1.00 43 4.0 4.1 4.0 1.03 44 1.7 1.6 1.6 0.94 45 1.6 1.9 1.5 1.19 46 1.8 1.8 1.7 1.00 47 4.1 4.4 3.9 1.07 48 3.6 3.8 3.6 1.06 49 1.6 1.6 1.6 1.00 50 4.2 4.6 4.2 1.10 51 2.0 2.0 1.8 1.00

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116 Table A-17 Continued Mussels External Top Internal External Bottom Internal/Top 52 4.5 4.5 4.3 1.00 53 2.1 1.9 1.7 0.90 54 4.0 4.0 3.9 1.00 55 4.6 4.4 4.3 0.96 56 4.8 4.5 0.0 0.94 57 4.4 4.4 4.2 1.00 58 4.6 4.3 4.1 0.93 59 4.2 4.2 4.2 1.00 60 1.8 1.9 1.7 1.06 61 1.6 1.9 1.6 1.19 62 1.7 2.0 1.6 1.18 63 4.8 5.0 4.8 1.04 64 4.6 4.5 4.5 0.98 65 4.3 4.5 4.1 1.05 66 4.5 4.4 4.3 0.98 67 4.1 4.2 3.9 1.02 68 2.0 1.8 1.6 0.90 69 2.0 1.9 1.7 0.95 70 1.9 1.8 1.9 0.95 71 1.9 1.8 1.9 0.95 72 1.8 1.8 1.6 1.00 73 5.0 4.9 4.9 0.98 74 3.9 3.8 3.6 0.97 75 3.8 3.8 3.4 1.00 76 1.7 1.9 1.6 1.12 77 3.7 3.9 3.4 1.05 78 1.7 1.6 1.5 0.94 79 4.0 4.2 3.9 1.05 80 2.0 1.7 1.6 0.85 81 4.6 4.9 4.5 1.07 82 4.2 4.4 0.0 1.05 83 4.6 4.4 4.4 0.96 84 1.7 2.0 1.6 1.18 85 1.9 1.5 1.7 0.79 86 1.9 1.7 1.6 0.89 87 5.2 4.5 5.2 0.87 88 1.9 1.7 1.7 0.89 89 1.6 1.8 1.6 1.13 90 1.7 1.9 1.6 1.12 91 4.5 4.5 4.5 1.00 92 3.8 3.4 3.6 0.89 93 3.7 3.8 3.6 1.03 94 1.6 1.9 1.6 1.19 95 4.3 4.4 4.3 1.02 96 4.6 4.5 4.1 0.98 97 1.8 1.7 1.6 0.94 98 4.2 4.3 4.1 1.02 99 4.8 4.9 4.5 1.02 100 4.1 4.0 4.1 0.98

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117 Table A-18. Gamma Ray Irradiated Mussels in kGy Mussels External Top Internal External Bottom Internal/Top 1 1.7 1.7 1.6 1.00 2 3.9 3.8 3.7 0.97 3 2.0 1.6 1.6 0.80 4 2.0 1.9 1.9 0.95 5 4.5 4.4 4.3 0.98 6 1.9 1.6 1.5 0.84 7 3.9 3.8 3.8 0.97 8 4.2 4.0 3.8 0.95 9 2.0 1.7 1.7 0.85 10 5.0 5.0 4.9 1.00 11 2.0 1.9 1.7 0.95 12 4.6 4.5 4.1 0.98 13 2.2 1.8 1.8 0.82 14 5.0 4.8 4.4 0.96 15 1.9 1.7 1.6 0.89 16 4.4 4.3 4.2 0.98 17 1.8 1.6 1.6 0.89 18 4.9 4.6 4.5 0.94 19 2.2 1.9 1.7 0.86 20 1.7 1.6 1.6 0.94 21 1.9 1.8 1.7 0.95 22 4.6 4.5 4.4 0.98 23 1.9 1.6 1.6 0.84 24 1.9 1.8 1.7 0.95 25 1.8 1.6 1.6 0.89 26 4.9 4.6 4.3 0.94 27 4.6 4.6 4.6 1.00 28 1.6 1.6 1.6 1.00 29 2.0 1.8 2.0 0.90 30 1.8 1.7 1.7 0.94 31 1.9 1.8 1.8 0.95 32 2.0 1.7 1.6 0.85 33 4.6 4.5 4.3 0.98 34 4.0 3.7 3.6 0.93 35 3.9 3.8 3.6 0.97 36 4.6 4.6 4.6 1.00 37 4.6 4.5 4.4 0.98 38 4.4 4.4 4.3 1.00 39 2.1 1.9 1.8 0.90 40 1.7 1.7 1.7 1.00 41 1.7 1.6 1.6 0.94 42 4.3 4.3 4.2 1.00 43 4.1 4.0 4.0 0.98 44 1.7 1.6 1.6 0.94 45 1.9 1.6 1.5 0.84 46 1.8 1.8 1.7 1.00 47 4.4 4.1 3.9 0.93 48 3.8 3.6 3.6 0.95 49 1.6 1.6 1.6 1.00 50 4.6 4.2 4.2 0.91 51 2.0 2.0 1.8 1.00

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118 Table A-18 Continued Mussels External Top Internal External Bottom Internal/Top 52 4.5 4.5 4.3 1.00 53 2.0 1.9 1.7 0.95 54 4.0 4.0 3.9 1.00 55 4.6 4.4 4.3 0.96 56 4.8 4.6 4.5 0.96 57 4.4 4.4 4.2 1.00 58 4.3 4.1 4.1 0.95 59 4.2 4.2 4.2 1.00 60 1.9 1.8 1.7 0.95 61 1.9 1.6 1.6 0.84 62 2.0 1.7 1.6 0.85 63 5.0 4.8 4.8 0.96 64 4.6 4.5 4.5 0.98 65 4.5 4.3 4.1 0.96 66 4.5 4.4 4.3 0.98 67 4.2 4.1 3.9 0.98 68 2.0 1.8 1.6 0.90 69 2.0 1.9 1.7 0.95 70 1.9 1.9 1.8 1.00 71 1.9 1.8 1.8 0.95 72 1.8 1.8 1.6 1.00 73 5.0 4.9 4.9 0.98 74 3.9 3.8 3.6 0.97 75 3.8 3.8 3.4 1.00 76 1.9 1.7 1.6 0.89 77 3.9 3.7 3.4 0.95 78 1.7 1.6 1.5 0.94 79 4.2 4.0 3.9 0.95 80 2.0 1.7 1.6 0.85 81 4.9 4.6 4.5 0.94 82 4.5 4.4 4.2 0.98 83 4.6 4.4 4.4 0.96 84 2.0 1.7 1.6 0.85 85 1.9 1.7 1.5 0.89 86 1.9 1.7 1.6 0.89 87 4.9 4.8 4.5 0.98 88 1.9 1.7 1.7 0.89 89 1.8 1.6 1.6 0.89 90 1.9 1.6 1.7 0.84 91 4.5 4.5 4.5 1.00 92 3.8 3.6 3.4 0.95 93 3.8 3.7 3.6 0.97 94 1.9 1.6 1.6 0.84 95 4.4 4.3 4.3 0.98 96 4.6 4.5 4.1 0.98 97 1.8 1.7 1.6 0.94 98 4.3 4.2 4.1 0.98 99 4.9 4.8 4.5 0.98 100 4.1 4.0 4.1 0.98

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119 APPENDIX B OYSTER, CLAM AND MUSSEL PICTURES Figure B-1. Picture of oysters with dosi meter envelopes placed on them (6/8/05)

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120 Figure B-2. Picture of clams with dosim eter envelopes placed on them (6/8/05)

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121 Figure B-3. Picture of musse ls with dosimeter envelopes placed on them (6/8/05)

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122 LIST OF REFERENCES Blake, P.A., R. E. Weaver, D. G. Hollis and P.C. Heublein. 1979. Disease caused by Vibrios. Annu. Rev. Microbiol. 34:341-367 Blake, P. A. 1983. Vibrios on the half shell: What the walrus and the carpenter didnt know. Ann. Intern. Med. 99:558-559. Blake, P. A., R. E. Weaver and D. G. Ho llis. 1980. Diseases of humans (other than cholera) caused by Vibrios N. E. Jour. Med., 300(1):1-5. Blogoslawski, W.J. and M. E. Stewart. 1983. Depuration and Public Health. J. World Maric. Soc. 14: 535-540. Berlin, D. L., D. S. Herson, D. T. Hicks and D. G. Hoover. 1996. Response of Pathogenic Vibrio Species to High Hydrostatic Pressu re. Appl. And Envir. Micro. 65:27762780. Carver, J. H., T. J. Connors, L. J. Ronsivalli, and J. A. Holston. 1967. Shipboard irradiator studies. Report to USAEC on Contact No. AT(49-11)-1889. Bur. Com. Fish. Tech. Lab., Gloucester, Miss. Centers for Disease Contro l and Prevention [CDC]. 2003. Vibrio vulnificus Technical Information. http://www.cdc.gov/ncidod/dbmd/dise aseinfo/vibriovulnificus_g.htm Accessed 2005 January 25. Code of Federal Regulations [CFR]. T itle 21, Part 179. April 1, 1994. Food and Drug Administration, Health and Hu man Services. Washington, DC. Connors, T. J. and M. A. Steinberg. 1964 Pr eservation of fresh unfrozen fishery products by low-level radiation. II. Or ganoleptic studies on radia tion pasteurized soft-shell clam meats. Food Technol. 18(7):113-116. Dixon D. W. 1992. The effect s of gamma radiation (60Co) upon shellstock oysters in terms of shelf life and ba cterial reduction, including Vibrio vulnificus levels. M. S. Thesis. University of Florida, Gainesville. Dixon, D. W. 1996. The influence of gamma radiation upon shellstock oysters and culturable and viable but nonculturable Vibrio vulnificus Ph.D. Dissertation. University of Florida, Gainesville.

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123 Dixon, D. W. and G. E. Rodrick. 1998. Effect of gamma radiation on shellstock oysters. In: Combination Processes for Food Irra diation. International Atomic Energy Agency. Vienna. 97-110. DuPont, H. L. 1986. Consumption of raw shellf ish: is the risk now unacceptable? N. E. Journ. Med. 314:707-708. Elias, P.S. and A. J. Cohen. 1983. Recent A dvances in Food Irradiation. Amsterdam and New York: Elsevier Biomedical Press. Farkas, J. 2001. Physical methods of food preservation. In : Food Microbiology Fundamentals and Frontiers. (Eds. M. P. Doyl e, L. R. Beuchat and T. J. Montville) Washington, DC: ASM Press. 580-581. Food and Drug Administration [FDA] and Inte rstate Shellfish Sa nitation Conference [ISSC]. 2003. Vibrio vulnificus risk management of oysters. FDA mandate. Gardner E. A. and Watts B. M. 1957. Effect of ionizing radiation on southern oysters Food Technology. 11:329-332. Grez, N., Rowley, D.B. and Matsuyama, A. 1983, The Action of Radiation on Bacteria and Viruses, in Preservation of Foods by Ionizing Radiation, Vol 2. CRC Press, Boca Raton, FL. Harewood, P., S. Rippey and M. Montesalvo. 1 994. Effect of gamma irradiation on shelf life and bacterial and viral loads in hard-shelled clams ( Mercenaria mercenaria ). Appl. Environ. Micro. 60(7):2666-2670. Henkel, J. 1998. Irradiation: A safe measur e for safer food. FDA Consumer MayJune Publication No (FDA) 98-2320 Howard, R. J., B. Brennaman, and S. Lieb. 1986. Soft-bacteria infections in Florida due to marine Vibrio bacteria. Fla. Med. J. 73:29-34. Kelly, M. T. 1982. Effect of temperature and salinity on Vibrio ( Beneckea ) vulnificus occurrence in a Gulf Coast environmen t. Appl. Environ. Microbiol. 44:820-824. Kelly, M. T., and E. M. Dan Stroh. 1988. O ccurrence of Vibrion aceae in natural and cultivated oyster populations in the Pacific Northwest. Diagn. Microbiol. Infect. Dis. 9:1-5. Kilgen, M. B., M. T. Cole and C. R. Hackney. 1988. Shellfish sanitation studies in Louisiana. J. Shellfish Res. 7(3):527-530. Klontz, K. C., S. Lieb, M.Schreiber, H. T. Janowski, L. M. Baldy and R. A. Gunn. 1988. Vibrio vulnificus infections in Florida, 1981-1987: clinical and epidemiological features. Ann. Intern. Med. 109:318-323.

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124 Liuzzo J. A., Novak A. F., Grodner R. M., Rao M. R. 1970. Radiation pasteurization of gulf shellfish, Louisiana State University for the U.S. Atomic Energy Commission, Technical Information Division, Re p. No. ORO-676, Baton Rouge, LA. 42. Lohaharanu, P., C. Prampubesara, K. Kraisorn, and K. Nouchpromool. 1972. Preservation of crabmeat by gamma irradi ation. Thai. AEC-58. Office of Atomic Energy for Peace, Bangkok.. Mallett, J. C., L. E. Beghian and T. Metcal f. 1991. Potential of irra diation technology for improved shellfish sanitation. In: Mollus can Shellfish Depuration. (Eds. W. S. Otwell, G. E. Rodrick, and R. E. Martin). Boca Raton, FL: CRC Press, Inc. 247258. Mestey, D., G. E. Rodrick. 2003. A Compar ison of cryogenic freezing techniques and their usefulness in reduction of Vibrio Vulnificus in retail oysters. In: Molluscan Shellfish Safety. (Eds. A. Villalba, B Reguera, J. L. Romalde and R. Beiras).Intergov. Oceanograph. Comm. Of UNESCO. 467-474. Metlitskii, L. V., V. N. Rogachev and V. G. Krushchev. 1968. Radiation Processing of Food Products. Oak Ridge, TN: Oak Ridge National Laboratory, U. S. Atomic Energy Comission. Morris, J. G. Jr. and R. E. Black. 1985. Chol era and other vibrioses in the United States. N. E. Journ. Med. 312:343-50. Motes, M. L. and A. DePaola. 1996. Offshor e suspension relaying to reduce levels of Vibrio vulnificus in oysters Crassostrea virginica Appl. And Envir. Micro. 62:3875-3877. Nickerson, J. T. R. 1963. The Storage life Ex tension of Refrigerat ed Marine Products by low Dose Radiation Treatment: Explorati on of Future Food Processing Techniques. Cambridge, MA: MIT Press. Novak, A. F., J. A. Liuzzo, R. M. Grodner and R. T. Lovell. 1966. Radiation pasteurization of Gulf Coas t oysters. Food Technol. 20:201. Oliver, J. D., R. A. Warner and D. R. Cleland. 1983. Distribution of Vibrio vulnificus and other lactose-fermenting vibrios in the marine environment. Appl. Environ. Microbiol. 44:1404-1414. Rodrick, G. E. and Dixon, D. W. 1994 Code of practices for the irradiation of seafoods. Prepared for the International Atomic Energy Agency. Slavin, J. W., J. T. R. Nickerson, S. A. Gol dblith, L. J. Ronsivalli, J. D. Kaylor, J. J. Licciardello. 1966. The quality and wholesom eness of radiation pasteurized marine products with particular reference to fish fillets. Isotopes and Radiation Technology. 2:365.

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125 Slavin, J. W., M. A. Steinberg, and T. J. Connors. 1963. Low level radiation preservation of fishery products. Report to U. S. Atomic Energy Commission on Contract No.AT(49-11)-1889. U.S. Fish and Wildlife Tech. Lab., Gloucester Mass. Stein, M. 1995. Historical perspectives, impor tance and definition of radiation terms. Proceedings from the 1st Annual IFT Short Course on the Practical Aspects of Food Irradiation. Section 4. Tampa, FL. October 16-17, 1995. Tacket, C. O., F. Brenner and P. A. Blake. 1984. Clinical features and an epidemiological study of Vibrio vulnificus infec tions. J. Infect. Dis. 149:558-561. Tamplin, M. L., G. E. Rodrick, N. J. Blake, and T. Cuba. 1982. Isolation and characterization of Vibrio vulnificus from two Florida estuaries. Appl. Environ. Microbiol. 44: 1466-1470. Urbain, W. M. 1986. Food Irradiation. Or lando, FL: Academic Press, Inc. Webb, T., T. Lang and K. Tucker. 1987. Food Irradiation: Who Wants It? London: Thorsons. Yamada, K., and K. Amano. 1965. Reduction of coliform numbers in shucked baby clam by gamma irradiation. Bull. Tokai Reg. fish. Res. Lab. No. 43:91-96.

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126 BIOGRAPHICAL SKETCH Arthur Grant Hurst Jr., the older of Art hur and Darlene Hursts two children, was born April 20, 1981, in Picayune, Mississippi. He graduated from Niceville High School in 1999. He was awarded the Bachelor of Scie nce degree from the University of Florida in May, 2003, from the Department of Food Science and Human Nutrition. He continued at the University of Florida for graduate study, in the Department of Food Science and Human Nutrition, in pursuit of the Master of Sc ience degree under the supervision of Dr. Gary E. Rodrick. He was awarded the Mast er of Science degree in December of 2005. Once graduated, Arthur plans to start a career working in th e food industry sp ecializing in food safety and quality assurance.