Risk of Salmonella Spp. for Fresh Market Tomatoes during Pre- and Post-Harvest Practices

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Material Information

Title:
Risk of Salmonella Spp. for Fresh Market Tomatoes during Pre- and Post-Harvest Practices
Physical Description:
1 online resource (249 p.)
Language:
english
Creator:
Valadez, Angela M
Publisher:
University of Florida
Place of Publication:
Gainesville, Fla.
Publication Date:

Thesis/Dissertation Information

Degree:
Doctorate ( Ph.D.)
Degree Grantor:
University of Florida
Degree Disciplines:
Food Science and Human Nutrition
Committee Chair:
DANYLUK,MICHELLE D
Committee Co-Chair:
SCHNEIDER,KEITH R
Committee Members:
GOODRICH,RENEE M
DEWDNEY,MEGAN M
HARDER,AMY MARIE

Subjects

Subjects / Keywords:
pesticides -- produce -- safety -- salmonella -- sanitation -- soil -- tomatoes
Food Science and Human Nutrition -- Dissertations, Academic -- UF
Genre:
Food Science and Human Nutrition thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract:
Three food safety objectives were investigated in pre- and post-harvest practices of fresh market tomato production. During tomato production in the field, the time between tomato harvest and field preparation for the next crop of tomatoes in Florida can range from two to five months, depending on the production district. The risks associated with Salmonella survival during the off-season of tomato production have not been investigated. A cocktail of Salmonella was inoculated into soils collected from four tomato-growing regions in Florida (Collier, Gadsden, Manatee, and Miami-Dade counties); tomatoes and tomato plant debris were added. Soils were stored at 15°C or 30°C for 6 months, prior to Salmonella enumeration.  In all cases but one, Salmonella populations declines were greatest in soil only, and survival was greatest when tomato and tomato plant debris was added to the soil. Salmonella persistence was increased by cooler temperatures and in the presence of tomato plant debris.  Salmonella can persist in Florida’s tomato field soils during the off-season and may be a source for pathogen contamination in tomato fields in subsequent seasons. During produce production, when contaminated water is used to mix foliar pesticides,the edible portions of fruits and vegetables may become contaminated following pesticide or fertilizer application.  The fate of Salmonella in tomato foliar fertilizer and pesticides simulating spray tanks, and on tomato fruits was evaluated. A cocktail and a single strain of Salmonella were inoculated in fertilizers and pesticides diluted in groundwater to the lowest recommended spray concentrations in Florida.  Fertilizers and pesticides were stored under refrigerated temperature (4°C) and temperatures that occur in the course of a normal growing season in Florida (15°C or 30°C) for 7 days, prior to Salmonella enumeration.  A cocktail and a single strain of Salmonella was spot- inoculated on locally purchased mature green round tomatoes and stored for 3 days at 21°C, prior to Salmonella enumeration. A crop of mature green round tomatoes were grown in a screenhouse and were treated with Salmonella-inoculated diluted pesticide solutions. Sprayed mature green tomato fruits were harvested after 3, 7 and 10 days post-pesticide application, prior to Salmonellae numeration. In all the fertilizers and pesticides at all temperatures, gradual population reductions were equal to or greater than that the groundwater control.  Salmonella populations did not increase under any condition. Some fertilizers and pesticides may support Salmonella survival over extended periods if left in spray tanks and may be a source for pathogen contamination in foliar application in produce fields. Postharvest water quality management represents one of the few unit operations that approach a true critical control point for fresh tomatoes.There is a lack of performance data for sanitizers currently in use that reflect conditions of commercial systems. An on-site assessment of ClO2treatment and microbiological water quality in dump tank and flume systems was conducted. Bacterial loads and pulp temperature of incoming and final washed round mature-green tomatoes were measured within commercial tomato packing operations. Results varied among trials, due to environmental and incoming fruit conditions.  This study provides in-plant data to develop data-based critical operating standards for ClO2 for the fresh-tomato industry.
General Note:
In the series University of Florida Digital Collections.
General Note:
Includes vita.
Bibliography:
Includes bibliographical references.
Source of Description:
Description based on online resource; title from PDF title page.
Source of Description:
This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility:
by Angela M Valadez.
Thesis:
Thesis (Ph.D.)--University of Florida, 2013.
Local:
Adviser: DANYLUK,MICHELLE D.
Local:
Co-adviser: SCHNEIDER,KEITH R.
Electronic Access:
RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2015-12-31

Record Information

Source Institution:
UFRGP
Rights Management:
Applicable rights reserved.
Classification:
lcc - LD1780 2013
System ID:
UFE0046241:00001