Front Cover
 Table of Contents

Group Title: Bulletin University of Florida. Agricultural Experiment Station
Title: Bulk handling of fresh citrus fruit
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00026799/00001
 Material Information
Title: Bulk handling of fresh citrus fruit
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 35 p. : ill., plan ; 23 cm.
Language: English
Creator: Prosser, David S
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1955
Copyright Date: 1955
Subject: Citrus fruits -- Handling   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
Statement of Responsibility: by D.S. Prosser, Jr. ... et al..
General Note: Cover title.
General Note: "In cooperation with Farmers Cooperative Service, United States Department of Agriculture."
 Record Information
Bibliographic ID: UF00026799
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: ltuf - AEN7463
oclc - 18279546
alephbibnum - 000926763

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Full Text

Bulletin 564 June 1955


(In cooperation with Farmers Cooperative Service, United States
Department of Agriculture)

Bulk Handling of Fresh Citrus Fruit




Single copies free to Florida residents upon request to


INTRODUCTION ................................. .... ... ....- 3

INITIAL EXPERIMENTS ....................................- ..-------..... 4

PILOT BULK ROOM CONSTRUCTION .--..-......---. -------................. 5

RESULTS IN PILOT ROOM --....-- ------................. -. --. .............-----.... 7

COMMERCIAL INSTALLATION AT WINDERMERE ...........-......-..................... 8

COMMERCIAL INSTALLATION AT SANFORD ......................... ................---..... 13

COMMERCIAL INSTALLATION AT VERO BEACH --...-.............--..--........-....... 17



FRUIT DAMAGE, DEGREENING AND DECAY STUDIES ........................................ 21

Results from Pilot Room Installation ..............-- .........---..-..---..... 21

Results of Trials at Commercial Packinghouses ..... ......-----................. 25

Windermere Method ..--.....--......-- ...----......---------- 25

Sanford Method .....---.........-----....................--- 27

COMPARISON OF COST OF VARIOUS METHODS ....--.............- ........ ..-------- ..- 28

SUMMARY ................-........----------------------------------...... ... -......... 34

ACKNOWLEDGMENTS .......-..........----.--------....... ---.......---------.. --- 35

Bulk Handling of Fresh Citrus Fruit

and J. K. SAMUELS1

Throughout preceding decades citrus growers and handlers
have looked for the day when the cost of moving citrus fruit
from tree to market could be substantially reduced. The custom-
ary practice of using the wooden field box as a handling unit
involves picking and hauling costs that amount to at least 2/
the cost of production. The loading, handling and repair of
the wooden field boxes make up a substantial portion of this
cost. In addition, box handling presents problems of labor,
morale and discipline in the field and packinghouse that can-
not be measured in economic terms.
Some years ago a number of processors and handlers of can-
nery fruit partially eliminated the wooden field box from their
operations. Fruit was picked and put into boxes in the grove
and these boxes were dumped directly into cannery bulk fruit
goats 2 in the grove middles. From there the goats usually
moved to a convenient roadside location near the grove where
the fruit would be dumped from the goat and loaded into a
bulk semitrailer truck by means of a paddle elevator. This
eliminated moving the boxes into the cannery. Variations of
this practice were found through the years and consisted of
attempts to pick directly into small carts or trucks which would
take the place of the box-goat system mentioned above. Some
of these methods have been adopted by various commercial or-
ganizations and may be found in use today.
The stimulus for handling fresh fruit in bulk from the field
through the packinghouse came during the 1947-48 citrus sea-
son when delivered fruit prices were exceptionally low. With
grapefruit widely quoted as low as 5 cents per box on the tree,
a tremendous amount of interest was generated in finding
SProsser, Asst. Engineer, and Grierson, Asst. Chemist, Citrus Experi-
ment Station, Lake Alfred; Thor, Assoc. Agr. Economist, Agricultural
Experiment Station, Gainesville; Newhall, Asst. Biochemist, Citrus Sta-
tion; and Samuels, Director, Marketing Division, Farmers Cooperative
Service, USDA.
"2 The term "goat" designates a stripped-down truck without cab, and
with narrow body floor for hauling fruit out of groves.

4 Florida Agricultural Experiment Stations

cheaper methods of handling. Several commercial concerns
experimented with various types of bulk handling of fresh
fruit by attempting, unsuccessfully, to adapt the cannery fruit
systems for this purpose.
Finally, industry groups in conjunction with the Citrus Ex-
periment Station of the University of Florida and the Research
and Marketing Division of the Farm Credit Administration,
U. S. Department of Agriculture, set up a cooperative project
at the Citrus Station, Lake Alfred, to determine if a feasible
method of bulk handling could be devised for fresh fruit.
The principal purpose of this bulletin is to present the results
of this project, together with a discussion of the merits of the
system developed and the evaluation of the economic savings
attendant upon bulk handling of fresh fruit.

In handling fresh fruit provision must be made for holding
the fruit in ethylene gassing chambers or degreening rooms for
one to three days to remove the green color. Thus, work was
begun in the fall of 1948 to develop a suitable degreening room
for handling the fresh fruit in bulk at the packinghouse. It
was thought that moving the fruit from field to degreening
room and from degreening room to packinghouse processing
lines could be handled by conventional methods in the initial
work. The major problem was mutually agreed to be the de-
velopment of a satisfactory room for degreening and storing
the fruit in bulk. Later such operations as presizing, pregrad-
ing, decay control and field handling would be added.
Consequently, several experimental degreening rooms were
constructed during the period 1949-1951, using various types
and configurations of internal baffle systems and external de-
signs. The wooden baffles used to support the fruit in some of
the bins were later discarded because they damaged the fruit
and limited the storage capacity. Experiments during the lat-
ter part of 1951 showed that baffles of softer material such as
cloth, foam rubber or belting tended to eliminate these diffi-
culties. Later experiments with various types of cloth showed
that untreated cotton press cloth known as S/8108 gave better
results than jute cloth or more expensive materials such as
nylon, orlon, canvas or treated canvas. By using this porous
cotton press cloth for supporting the fruit in the bins, the neces-
sity for other padding or "breaker" strips to slow or break the

Bulk Handling of Fresh Citrus Fruit 5

fall of fruit through the bin was eliminated. In addition, the
porous cloth allowed proper circulation of air and ethylene and
reduced damage from sand and scratching or bruising of the
fruit in the bins.
Model bins using this cloth to support the bulk fruit and
simple methods of belt loading and unloading from the bins
were experimentally successful. A pilot room was subsequently
constructed in the summer of 1952 with the cooperation of the
Haines City Citrus Growers Association at their packinghouse
in Haines City.

The bulk coloring rooms at Haines City were constructed of
exterior wooden walls with cotton press cloth baffles to support
the weight of the fruit while it was being degreened. The
cotton cloth was reinforced and supported in place by strips
of parachute webbing sewed to the cloth. Metal grommets
through the ends of this webbing and ropes tied through the
grommets held the cloth in its proper shape and slope. Wire
tent slides enabled the ropes to be quickly and easily tightened
whenever necessary.
Four separate bins were constructed, each capable of holding
150 boxes of fruit. Warm air and ethylene were supplied by an
external duct, radiator and fan system, warm air being sup-
plied through a duct under the room and being drawn off by a
duct at the top of the room. As shown in the accompanying
diagram (Fig. 1), the top and bottom baffles of the room were
of standard slatted wood construction. The fruit was carried
to the room by means of an elevator and belt system and en-
tered the room through doors at the top. The elevator con-
sisted of an endless belt with wooden paddles that carried the
fruit without dragging it. On entering the bin, the fruit rolled
down the wooden top baffles and dropped off onto the cloth
baffles at the rear at the point in the diagram labeled "A".
From there it dropped down to "B", "C", etc., until it reached
the lowermost baffle "D". From there it rolled to the front of
the room on the slanted wooden bottom baffle "E" and rested
against the padded doors in front "F".
As more fruit entered it covered the bottom baffle with a
layer of fruit and backed up through the cloth baffles "D", "C",
"B", "A", etc., until it filled the top wooden baffle up to a point
"X". Then the door "Y" was opened and fruit descended through

6 Florida Agricultural Experiment Stations

the second series of canvas baffles until it dropped off the lower
baffle "Z" onto the layer of fruit below. This arrangement made
certain that fruit never dropped onto the hard wood. After
this section was filled with fruit, door "Q" was opened and the
process repeated. When the room was completely filled the
flow of fruit was shut off and the upper doors were closed. The
warm air and ethylene were then circulated in proper propor-
tions until the fruit was degreened.

-- --- s--
Shau iing ond FeI Root

mn1 to-* i"oc
6"'s With f"Crookl, E" 6e So.R t
Lo gX All Ed-ge SorTdo. Co S ON..e
Cooo -- All

Floor Sealed With Felt

Fig. 1.-Diagram of pilot bulk coloring room at Haines City Citrus
AGrowers' Association

To unload the room after degreening, the padded doors "F"

were opened and the fruit was rolled out onto the unloading
belt which then delivered it to the packinghouse. It was found
that oranges unloaded much more easily than did grapefruit and
that it was sometimes necessary to shake the cloth slightly to
start the grapefruit moving. One advantage of the cloth is

or movement of fruit in the bin will cause movement of the
belt which then delivered it to the packinghouse. It was found

that it was sometimes necessary to shake the cloth slightly to
start the grapefruit moving. One advantage of the cloth is
that it is not rigid as is a wooden baffle and therefore vibration
or movement of fruit in the bin will cause movement of the

Bulk Handling of Fresh Citrus Fruit 7

cloth and help to prevent jamming of the fruit during unload-
ing. Preventing the ropes and canvas baffles from drooping or
bagging helped to prevent fruit from hanging up on the baffles
when unloading.
Because of the large dimensions of the room in relation to
the air flow from the duct it was found that the warm air
was traveling under the lower wooden floor to the highest point
and then rising through the rear of the room. This channeling
of the air tended to make the fruit heat and color unevenly;
consequently, canvas curtains were suspended under the wooden
bottom baffle and the duct system was arranged to give equal
amounts of warm air and ethylene to all parts of the room.
Insulation was employed on the north and west sides to protect
them from outside cold winds.

These rooms were completed in time to obtain satisfactory
fruit runs in the spring of 1952 on regreened Valencia oranges.
Degreening was good and damage was not significantly in-
creased as compared to regular field box handling.
During the summer of 1952 a presizer and a pregrader were
added ahead of the room so that effective capacity of the bins
could be increased by the amount of fruit rejected as off-size
or unsound. A Dowicide-hexamine 3 fungicide tank also was
installed. By washing and Dow-hex dipping the fruit, dirt
and twigs were removed which interfere with the proper load-
ing and unloading of the fruit on the baffles if allowed to ac-
The use of a Dow-hex pretreatment when conducted in ac-
cordance with specific recommendations is a satisfactory inhibi-
tor for damage caused by blue mold and stem-end rot. This
is particularly important here, since the bulk handling of fruit
allows Dow-hex applications many hours or even days earlier
than if the fruit were handled in boxes. However, results using
Dow-hex on the fruit without drying showed a definite retarding
of the degreening process. When the fruit was properly dried
there was still a retarding of degreening, although it was not
as pronounced.

Dowicide-hexamine refers to treatment with sodium orthophenylphenate
and hexamethylene-tetramine decay control solution. E. F. Hopkins and
K. W. Loucks. Preservation of Citrus Fruits. U. S. Pat. 2,674,537, April
6, 1954.

8 Florida Agricultural Experiment Stations

(Handling Fruit in Carts to Packinghouse)
After observing the experimental pilot room at Haines City,
the Chase Investment Company converted their packinghouse
at Windermere, Florida, to this system. The installation was
completed in the fall of 1952 and the house operated commerci-
ally through the 1952-53 season in a satisfactory manner. In
the opinion of observers and officials of the company, the de-
greening accomplished was as good as, or superior to, fruit
colored in boxes.
To facilitate the handling of the fruit and to obtain the most
economical packinghouse operation, their entire system was
revamped so as to handle fruit in bulk from the grove to the
final packing operation. Briefly, the fruit is picked and dumped
in the grove directly into two-wheel carts holding 20 boxes of

Fig. 2.-Pickers loading two-wheel carts in grove (Windermere).

~ kV.

-ir2 4. ,.~5 .

Bulk Handling of Fresh Citrus Fruit 9

fruit per cart (Fig. 2). To eliminate objections by the picking
crews as to picking wages or rates, the carts are divided into
equal sections and two pickers fill one side each. When four
carts are filled they are hitched together as a train and pulled
into the packinghouse by a light tractor.

Fig. 3.-Unloading bulk carts on packinghouse dump belt (Windermere).

At the packinghouse an especially designed ramp is built so
that when the carts are driven over it they are pitched slightly
on one side towards a dump belt conveyor. The tractor driver
then walks along the line of carts, opening doors on the sides
next to the belt to allow the fruit to roll out on the belt and

10 Florida Agricultural Experiment Stations

be carried into the packinghouse (Fig. 3). The processing ma-
chinery is so arranged that this fruit moves from the dump
belt to a presizer, where reject sizes are discarded to the can-
ney fruit bins. From the presizer the fruit moves to a Dow-hex
dip, washer, pregrader (where rotten, damaged or malformed
fruits are eliminated) and elevator dryer. After leaving the
dryer the fruit moves on distributor belts to loading doors (Fig.
4) at the top of the bulk coloring rooms, where it is placed for
storage or degreening (Fig. 5).
The labor necessary to accomplish the above operations con-
sists of a tractor driver, two pregraders and a man to supervise
the loading of the rooms. Except for the tractor driver, none
of these jobs require specialized skill.
After the fruit has been degreened, one man has the job of
releasing it from the bottom of the bulk coloring rooms onto a

Fig. 4.-Fruit entering loading doors at top of bulk coloring bin


Bulk Handling of Fresh Citrus Fruit 11

conveyor belt (Fig. 6) which carries it to the waxer, polisher,
color applicator, etc. Presizing and grading before coloring in-
creases the capacity of the coloring rooms substantially with
respect to marketable fruit, and eliminates the detrimental
effect of split, rotten or decayed fruit.


Fig. 5.-View inside bulk room showing fruit supported by open mesh
canvas baffle (Windermere).

Other advantages attendant upon the use of this system in-
clude benefits derived from elimination of early morning labor

12 Florida Agricultural Experiment Stations

crews to distribute boxes or the later afternoon crews to return
fruit loads left in the grove after the pickers have finished.
Normally the entire crew moves out together in the morning
and returns together at night. Also, some efficiency may be
derived from the use of oversized picking bags if they can be
used, since the size of the bags is not limited by the volume of
a wooden field box.

Fig. 6.-Degreened fruit from bulk room is discharged by gravity onto belt
for final packinghouse operations (Windermere).

The class of labor also is reduced from that required for the
usual "back breaking" loading, handling, etc., to that used to
merely guide the fruit on proper belts or to proper loading doors.

Bulk Handling of Fresh Citrus Fruit 13

This tends to raise the morale of the entire operation and to
reduce labor turnover, injuries and complaints. If desired,
handicapped workers or women may be used to handle the
bulk fruit and to perform the operations requisite with good
packinghouse procedure.
Other benefits include indirect savings in the packinghouse
operation due to less grade and size variation and a higher re-
turn obtained for the fruit presized out and sent to the can-
nery, since it is sold as "field-run" fruit instead of packinghouse
elimination. Also, packinghouse handling charges for this fruit
sent to the cannery are substantially reduced.
A disadvantage found in the system is that occasionally all
of the fruit will not unload by itself from a bulk coloring room,
particularly when handling grapefruit. This requires the man
in charge of unloading to shake the canvas in some fashion to
discharge any fruit that may be left behind. However, this
does not become an additional operation expense, since this man
must be present to control the flow of discharged fruit. A
limitation of the system in use at Windermere is that the use
of the tractor to pull a train of trailers is limited to a radius
of about six miles from the packinghouse. However, the intro-
duction of a newer commercial system of field handling during
1953 by Chase Investment Company at their house at Sanford
for hauling bulk fresh fruit over long distances extends this
operation radius to any distance normally in use for fresh fruit

(Handling Fruit in Wire Baskets to Semitrailer,
Semitrailer Hauling Fruit to Packinghouse)
The system in use today at Sanford includes the use of metal
baskets and tractors equipped with hydraulic lifting systems to
carry these baskets out of the grove and dump the fruit into
a semitrailer truck. The trailer body is equipped with cloth
baffles to break the fall of the fruit and to prevent scratching
and bruising during loading. The baskets hold the equivalent
of 10 boxes each and every picker has his individual basket
(Fig. 7). The basket frame is constructed of steel strap and
angle iron, with flattened expanded metal welded to the frame
to form the body. A solid steel sheet bottom reduces the effect
of sand entering when the baskets are placed in the grove. The

14 Florida Agricultural Experiment Stations

baskets are designed with sloping sides so that they will fit into
one another or "nest" for storage or carrying.


Fig. 7.-Pickers filling wire basket in grove (Sanford).

The tractor is designed to carry a filled basket on front and
rear (Fig. 8), but can lift and dump only with the hydraulic
arms in front. The usual method is for the tractor to bring out
two baskets from the grove to the semi. The driver dumps
the one held in front (Fig. 9) and picks up the filled basket left
at the dumping site from his previous dumping round and emp-
ties this into the semi. He then leaves the filled rear basket
near the dumping site and picks up the two empty baskets for
return to the pickers.

Fig. 8.-Tractor carrying filled baskets on front and rear (Sanford).

The semitrailer has a capacity when fully loaded of 420 boxes,
although the usual practice is to carry only 320 boxes when
handling fresh fruit in order to reduce damage due to sheer
weight of fruit. One side is equipped with small doors along
the length of the body so that the truck may be unloaded from
the side.

Fig. 9.-Tractor driver dumping basket into trailer (Sanford).

16 Florida Agricultural Experiment Stations

An arrangement of cloth baffles, constructed from several
layers of the same porous press cloth used in the coloring rooms,
is used to protect the falling fruit from damage during load-
ing. These baffles are placed at two points in the trucks, at 1/4
trailer length from each end, as shown in the accompanying
diagram (Fig. 10). The cloth baffles are supported indepen-
dently from the wooden, trailer sides by a steel framework that
enables them to be tightened and securely held. Padding is
placed on the trailer floor next to the baffles.
Fruit falls onto each baffle arrangement (Fig. 11) until it fills
with fruit. The overflow runs onto the padded trailer floor be-
tween the baffle systems until a height of approximately 18
inches from the top is reached. Then the baskets are emptied
directly on this protective layer of fruit between the baffle sec-
tions until the trailer is filled to capacity.
When the semi is filled, it is driven to the packinghouse where
a special ramp tilts it sideways and allows the fruit to roll out
of the truck side onto a belt which carries it to the presizer, etc.
(Fig. 12). From this point the fruit is handled exactly as in the
Windermere house.

Fig. 10.-Interior of semitrailer showing cloth baffle and padding
on floor (Sanford).


Bulk Handling of Fresh Citrus Fruit 17

Fig. 11.-Fruit falling from basket onto cloth baffle and padded
floor (Sanford).

(Handling Fruit in Field Boxes to Packinghouse)
Another variation of the bulk fruit system may be found at
the Vero Beach packinghouse of the Indian River Exchange
Packers. This house was converted to bulk handling in the
summer of 1953 and operated commercially during the 1953-54
season. In this system the fruit is picked into the wooden field

18 Florida Agricultural Experiment Stations

boxes and the goats move the filled boxes from the grove to the
packinghouse platform. At this point the boxes are dumped
automatically and the fruit goes to a presizer and thence to
the bulk degreening rooms. The fruit is not washed or treated
prior to entering the rooms. The boxes are immediately re-
turned to the grove. This reduces the number of boxes required
for packinghouse operation, since no boxes are tied up in color-
ing rooms.
Although the savings in labor and handling are not as large
in the Vero Beach system as in either the Windermere or the
Sanford system, it enabled the house to be converted at no addi-
tional capital outlay over usual seasonal expense, since the
bulk fruit rooms were built with funds that would normally
be used in buying new boxes. As the remaining field boxes
wear out they may be replaced by one of the field bulk handling
systems previously described. This step by step conversion

Fig. 12.-Semitrailer unloading on tilted ramp at packinghouse (Sanford).

B- .- S-^^p -

0 -.--' 1 I

Bulk Handling of Fresh Citrus Fruit 19

allows labor and management to become adjusted to one phase
of bulk handling before moving to the next.

In groves where the trees have grown into the middles it is
necessary to "hedge" or cut out these middles to predetermined
widths to facilitate the movement of tractors, trailers or other
equipment through the grove, as well as to reduce damage to
both trees and equipment. Advice on hedging and a descrip-
tion of machinery for accomplishing this work quickly and
economically may be found in recent publications.4

The bulk handling systems described above are those com-
mercially in use at present. No doubt other efficient methods
will be devised that will bring as many or more advantages
to the fresh fruit handler and packer. Several modifications
of these systems have been experimented with by the authors,
but it is believed that the three systems presented will cover
almost any situation where fresh fruit is handled. Two other
variations that have been tried should be mentioned at this
time. One of these-moving the wire baskets from the grove
to the packinghouse and placing them directly in a standard
degreening room-is unsatisfactory, due to the large number of
baskets needed, the large amount of labor or equipment neces-
sary for handling the baskets, the lowered capacity of the de-
greening rooms, and the damage to the fruit by prolonged
pressure against the expanded metal basket sides.
The second variation includes the use of carts in the grove,
as is done in the Windermere system; but, instead of moving
them directly to the packinghouse, they are moved to the side
of the road next to the grove. Here they are dumped onto a
platform and discharged into a special elevator which carries
the fruit into a semi equipped with canvas baffles and suited for
moving fruit long distances. This modification has merit over
the wire basket and tractor lift system. Less sand gets into
Prosser, D. S., Jr. Hedging machine for citrus groves. Fla. Agr. Exp.
Sta. Bul. 519. 1953.
Norris, R. E. Hedging of Florida citrus. Fla. Agr. Ext. Ser. Cir. 115.

20 Florida Agricultural Experiment Stations

the carts than into the baskets and there is less disturbance of
the trees, soil and roots by simply pulling carts. In addition,
less complex tractor equipment can be used, tractor mainte-
nance is lower and less experienced drivers can be employed.

Fig. 13.-Experimental use of carts in grove to load semitrailer. In newer
method carts dump directly into special elevator that fills trailer.

Disadvantages of the cart-to-semi system include the neces-
sity for a cart-tilting device, a dump belt and a special fruit
elevator that will not damage the fruit in loading the semi-
trailer. In addition, the carts take up more space than wire
baskets in hauling to the grove and therefore present a hand-
ling problem. An experimental setup for using the carts to
load a semi is shown in Fig. 13. It can be noted that the lack

Bulk Handling of Fresh Citrus Fruit 21

of a proper ramp for tilting the carts requires that the workers
push the fruit from the carts to the loading belt. Newer
methods being tried by industry groups include dumping the
carts directly into the fruit loader, which will eliminate the
need for the additional ramp and belt system. Others are de-
signing carts that will disassemble and can be stacked or nested
for easy hauling and distribution.
All of these variations tend to show that the disadvantages
mentioned may be overcome or reduced and that this system of
grove carts-to loader-to semitrailer may actually become the
most feasible bulk handling method when groves are more than
six miles from packinghouse, and hence gain extensive com-
mercial acceptance.

Since the success of bulk handling obviously depends upon
whether the system can be installed without materially increas-
ing damage to the fruit, experiments were carried out in the
pilot room installation (at Haines City C.G.A.) to determine
the effect of bulk handling on fruit damage and subsequent
In all the experiments reported here, the following method
was used. Samples from the various handling methods were
stored at 70 F. until three weeks from picking date. Thus,
time at 700 F. was three weeks, less the degreening period which
varied from 12 to 72 hours depending on the season, variety
and needs of the commercial packinghouse. These samples
were examined at weekly intervals and all nonsalable fruit
recorded. Separate records were kept of losses from stem-end
rot and blue and green molds. Cut and bruised fruit were not
recorded separately, as such damaged fruit held under these
conditions rapidly succumbed to some form of decay and were
so noted.
In these experiments treatments usually involved approxi-
mately 150 boxes each. From these, two box samples were
taken at random as the fruit was run into the commercial
packinghouse. It was these samples that were held for decay
studies. Precise experimental designs were, unfortunately, not
possible, since these experiments were often dependent on the

22 Florida Agricultural Experiment Stations

fruit being available in sufficient quantity, the operating sched-
ule of the commercial packinghouse and the fact that opera-
tions often had to be divided between the experimental pack-
inghouse at the Citrus Experiment Station and the pilot plant
at Haines City.
Table 1 shows a condensation of the results from six experi-
ments with early and late Duncan grapefruit and nine ex-
periments with Valencia oranges carried out in the season of
1952-53. In these 15 experiments the overall average of all
types of loss at three weeks from picking was 23 percent for
bulk-handled fruit and 24 percent for box-handled fruit. Sta-
tistical analysis showed no significant difference between the
two treatments for either Duncan grapefruit or Valencia

OCTOBER 1952-JUNE 1953.
Duncan Grapefruit Valencia Orange
Type of Avg. of 6 Runs Avg. of 9 Runs, 3/17
Decay 10/29, 11/4, 11/10 3/30, 4/8, 4/14, 4/27
3/19, 3/25, 5/4 [ 5/12, 5/19, 5/28, 6/2

S.E.R.* .......... 19.2 Percent 18.7 Percent
Mold** .......... 5.1 Percent 3.0 Percent
Total t .......... 24.3 Percent 21.7 Percent


S.E.R. .......... 18.5 Percent 23.5 Percent
Mold ............. 3.2 Percent 2.8 Percent
Total .............. 21.7 Percent 26.3 Percent

S.E.R. = Stem-end rot.
** Mold = All decay other than stem-end rot, largely blue and green mold.
"? Total loss = At 3 weeks from picking (weighted average all runs, all types of fruit).

Further experiments were carried out in the fall of 1953.
Results of these are shown in Table 2. In some of these ex-
periments the fruit was washed prior to entering the degreen-
ing bins and some lots were treated with Dow-hex fungicide,
since such practices are well suited to bulk handling.



Duncan Grapefruit Hamlin Orange Pineapple Orange t
Treatment (Avg. of 3 Runs 9/23, 9/29 (Avg. of 2 Runs 11/17 and (Single Run 12/14)
and 10/5) 12/1)
1 Week* 2 Weeks 3 Weeks I 1 Week I 2 Weeks I 3 Weeks I 1 Week 2 Weeks 3 Weeks
Percent losses: BULK

Unwashed ........................ 3.0 13.0 21.25 2.6 16.6 19.0 4.5 23.75 39.25
W ashed ........................... 1.3 10.25 17.2 .... ....... ...........
Washed and Dow-hex...... 0.1 6.6 11.5 .... .... .... ....

Percent losses: BOXED

Unwashed (in bins)** .... .... ........ 0.5 17.5 26.5 .....
W ashed (in bins)** ........ 1.0 10.25 14.9 ....... ... ..........
Unwashed reg. handling (sample lost) 2.1 16.8 29.75 4.0 27.5 39.0

Time from picking. Fruit held at 70 F. following degreening at 850 F.
"** "In bins" indicates that check lots were degreened in boxes placed in the bulk bins, rather than in a commercial degreening room.

24 Florida Agricultural Experiment Stations

With the early grapefruit there was an indication that both
the washing and Dow-hex treatments were clearly beneficial in
terms of reduced decay. Whether bulk handling or box handling
resulted in smaller loss depended on whether or not the bulk
handling was combined with Dow-hex. However, both wash-
ing and Dow-hex slowed up the degreening process. The ex-
tent of this effect varied with variety and season, but an
extension of 8 hours in 48 was about average. An exception
was early grapefruit, for which degreening was considerably
slowed by prior washing. Polishing the fruit after washing it
drastically slowed the degreening process; thus, polishing should
not be done prior to degreening.
In general the rate of degreening was better in bulk-handled
samples than in the control samples handled in a commercial
boxed fruit degreening room. During the fall of 1952 represen-
tative samples were checked with a visual colorimeter as well
as by the experienced eye of the packinghouse foreman. In
every case, color in the bulk-handled samples was as good as,
or better than, that in the samples from the commercially-run
box degreening rooms. In view of this, further studies on rate
of color change in bulk handled fruit were discontinued.
Further results from Dow-hex experiments are shown in
Table 3. This table includes runs with Hamlin and Parson
Brown oranges in the season of 1952-53 and Duncan grapefruit
in 1953-54. As will be seen in this table, the effect of the Dow-
hex treatment was to hold down decay very markedly, especially
during the first two weeks after picking. During this period,
the higher the amount of decay in the untreated fruit the larger
was the percentage reduction in decay due to the treatment.


Variety and Treatment Percent Total Losses from Decay
Picking Dates I 1 Week | 2 Weeks I 3 Weeks
Hamlin oranges Untreated 7.3 24.2 34.3
Dec. 1/52 Dow-hex 0.4 5.6 24.4
Parson Brown oranges Untreated 11.6 41.4 64.0
Dec. 11/12 Dow-hex 1.4 6.7 19.4
Duncan grapefruit Untreated 3.0 13.0 21.25
Average of 3 runs Dow-hex 0.1 6.6 11.5
9/23/53, 9/29/53 and

Bulk Handling of Fresh Citrus Fruit 25

All fruit in the experiments discussed above was picked in
boxes and hand dumped prior to degreening in bulk. Thus all
the decay results shown include whatever loss was due to dam-
age from the field boxes during transportation from the grove
to the packinghouse.
Considering the above experiments and others not detailed
here, it can be stated that bulk handling can be successful with
early, mid-season and late varieties of oranges and with grape-
fruit throughout the season. Valencia oranges are particularly
well adapted to bulk handling; also very little trouble is likely
to occur with grapefruit. If Dow-hex is not used, early oranges
have to be handled with particular care, especially the Parson
Brown variety. When hauled in dry, washed lightly and/or
dipped in Dow-hex and not held wet in the bins, Parson Brown
oranges can be successfully degreened in bulk. Thus, if the
recommended methods are followed, bulk handling is practical
for commercial varieties of oranges and grapefruit.


In the spring of 1954, experiments were carried out at two
commercial packinghouses using Valencia oranges. It was not
possible to maintain a standard experimental setup because
these two houses use two different versions of the bulk hand-
ling method and the experiments had to be fitted in with their
normal operating procedure. Hence, results from these houses
are presented separately.
Windermere Method (Carts to Packinghouse).-Four experi-
ments were carried out, all in duplicate. Since this packing-
house was degreening throughout this period, degreening was
possible for all replicates. A degreening room for boxed fruit
was available and hence the control fruit could be handled in
the regular manner.
The following treatments were used:
A. Picked into boxes, trucked into packinghouse and de-
greened in boxes.
B. Picked into trailers and delivered into the packinghouse.
Samples taken off the receiving belt prior to washing and Dow-
hex treatment.
C. Same as B but samples taken after washing and Dow-hex
treatment, prior to entering degreening bins.

26 Florida Agricultural Experiment Stations

D. Handled in bulk throughout, Dow-hex treated, degreened
and samples taken as fruit moved from bulk bin to packing-
All samples were stored at the packinghouse and examined
once a week for various types of decay.
Average total losses at three weeks from picking are shown
in Table 4. Since this house applied the Dow-hex treatment
to all fruit entering the degreening bins, it was not possible
to obtain a figure for fruit degreened in bulk without Dow-
hex. On all runs, the bulk-handled fruit (treatment D) showed
very much less loss than did the fruit handled in boxes and
without Dow-hex (treatment A).

Picked and De-
Picked, Trucked livered into Bulk Handled Bulk Handled
Date Degreened in Packinghouse Plus Dow-hex, Dow-hex and
Picked Boxes in Bulk Not Degreened Degreened in
Throughout Trailers Bulk
_(A) I (B) (C) (D)
Mar. 19 18.3 Percent 13.2 Percent 8.1 Percent 9.0 Percent
Mar. 26 35.5 Percent 25.2 Percent 10.2 Percent 7.2 Percent
Apr. 2 31.0 Percent 19.6 Percent 14.3 Percent 16.5 Percent
Apr. 9 16.5 Percent 14.5 Percent 14.0 Percent 4.0 Percent

Averages 25.3 Percent 18.1 Percent 11.7 Percent 9.2 Percent
L.S.D. (5% level) 7.9

Comparison of treatments B and C, both from the same bulk
lots, shows that on the average the Dow-hex treatment appar-
ently reduced total losses, although this just fails to be signifi-
cant at the 5 percent level. Comparison of treatments C and
D shows that there was no increase in decay due to bulk de-
greening of Dow-hex treated Valencia oranges. Comparison
of columns A and D shows that there was significantly less
total loss in the bulk handling and Dow-hex operation than in
box handling.
In these experiments, the percent reduction in decay due to
use of Dow-hex was approximately the same with losses from
both stem-end rot and penicillium (blue and green molds).

Bulk Handling of Fresh Citrus Fruit 27

To summarize the results of the Windermere experiments:
The combined bulk-handling and Dow-hex methods resulted in
63 percent less total loss than occurred with Valencia oranges
handled by the old box method without Dow-hex.
Sanford Method (Wire Baskets to Semi to Packinghouse).-
Performance trials at the Sanford packinghouse were limited
largely because the house closed for the season sooner than was
expected. A single trial was carried out, but this was in dupli-
cate throughout and both replicates are shown in Table 5.

S (C)
(B) Picked, Hauled,
Time (A) in Bulk.
from Picked, Hauled,j Washed,
Picking Sample [Picked, Hauled, in Bulk. No Dow-hex
(Weeks) Stored in Boxes Other Treated, Put
(Unwashed) Treatment I Through Bulk
____ Bins
1 Week Replicate A 0.0 Percent 0.6 Percent 0.0 Percent
Replicate B 0.0 Percent 0.0 Percent 0.0 Percent
Average 0.0 Percent 0.3 Percent 0.0 Percent

2 Weeks Replicate A 6.4 Percent 0.6 Percent 0.0 Percent
Replicate B 6.3 Percent 2.8 Percent 0.6 Percent
Average 6.35 Percent 1.7 Percent 0.3 Percent

3 Weeks Replicate A 12.0 Percent 8.0 Percent 2.3 Percent
Replicate B 17.7 Percent 9.1 Percent 2.9 Percent
Average 14.8 Percent 8.55 Percent 2.6 Percent

The following samples were taken:
A. Picked in boxes, trucked in as a normal "four-high" stack,
stored in same boxes until three weeks from picking.
B. Picked in bulk. Brought into the packinghouse in the
"baffled semi" and samples taken after discharging onto the
packinghouse receiving belt.
C. Same as B but put through the Dow-hex treatment,
washer, dried and then through the bulk bins.
Decay studies are shown in Table 5. Comparing samples A
and B, it will be noted that the samples picked in bulk and
hauled in the "baffled semi" suffered considerably less loss than

28 Florida Agricultural. Experiment Stations

those hauled in boxes. The most probable reason for this is
that in this bulk method one ninth as many fruits are in con-
tact with the container as in the case of box-handled fruit and
it is such contact that causes most of the mechanical damage.
Treatment C, the combination of the Dow-hex and bulk hand-
ling, resulted in losses of only 2.6 percent at three weeks from
picking, as compared with 14.8 percent for boxed fruit that
was not washed or otherwise treated. This represents an 82.5
percent reduction in total decay.

In this section the calculated costs of the various bulk meth-
ods discussed above are compared with standard field box pro-
cedures. Average total "cost per box picked" was determined
for each method by calculating the average fixed cost and the
average direct cost for the various weekly and seasonal vol-
umes. Costs were obtained by detailed analysis of all factors
appearing in the various systems. Complete breakdown of
those figures may be obtained from the Agricultural Economics
Department, University of Florida, Gainesville, Florida.5
The Windermere method is compared with the standard
method of loading the goats in the grove with filled field boxes,
moving the goats into the packinghouse and hand dumping the
field boxes after they have left the degreening rooms. These
two methods are analyzed for a situation in which the citrus
groves are within a six mile radius of the packinghouse (see
Fig 14 and Table 6).
Average total cost of the Windermere method is less than
that for the goat truck-field box method. Effect of volume per
week and volume per season on the average total cost per box
for picking, hauling, receiving and dumping oranges for the
Windermere and goat truck-field box methods is shown in Table
6 and illustrated graphically in Fig. 14. Differences in average
total cost can be estimated from Table 6 for various weekly
and seasonal volumes. Figure 14 illustrates the effect of in-
creasing volume per season for weekly average volumes of 5,000,
10,000 and 15,000 boxes.
The chart shows that the Windermere method resulted in
substantially lower costs than the standard method throughout

Thor, Eric. Cost Analysis of Bulk Handling Methods for Fresh Citrus.
Agr. Econ., Mimeo Report 55-1. 1954.

Bulk Handling of Fresh Citrus Fruit 29

the range of observed data. For a weekly volume of 5,000
boxes, the difference in average total cost per box for the two
methods was approximately 73/4 cents per box for a seasonal
volume of 100,000 boxes.


Volume Cost per Box for Total Seasonal Volume*
per At I At At I At
Method IWeek 100,000 200,000 300,000 1 Boxes
SBoxes I Boxes Boxes | 400,000
boxes dollars per box
Tractor 5,000 $0.2674 **
Bulk Trailer- 10,000 .2993 0.2633 0.2513 t
Bulk Degreening 15,000 .3312 .2793 .2620 0.2533

Goat Truck, 5,000 0.3446 **
Field Box-Hand 10,000 .3937 0.3384 0.3199
Dump 15,000 .4415 .3615 .3348 0.3215
(Standard Method)______
*Average total per box cost was calculated by adding average per box fixed cost and
average per box direct cost.
** Maximum volume that can be handled per season when operating at this weekly volume
is slightly in excess of 100,000 boxes.
t Maximum volume that can be handled per season when operating at this weekly volume
is slightly in excess of 300,000 boxes.

For 10,000 boxes weekly rate of output, the bulk degreening
method had lower average total cost per box than the field box
method by approximately 91/2 cents per box for a seasonal vol-
ume of 100,000 boxes; 71/2 cents for 200,000 boxes; and 7 cents
per box for 300,000 boxes.
For 15,000 boxes per week, difference in cost between the
two methods is approximately 11 cents per box for a seasonal
volume of 100,000 boxes, 81/4 cents per box for 200,000 boxes,
71/4 cents per box for 300,000 boxes and 68/ cents per box for
400,000 boxes.
The cost of the Windermere method cannot be compared
directly with those from other circumstances in which groves
are more than six miles from the packinghouse. Hence the
Sanford and Vero Beach bulk methods are compared with the
standard methods of loading the goats with filled field boxes,
transferring these to semitrailers, and moving the semitrailers
into the packinghouse; then either hand dumping or automati-

----- Goat truck, field box- Tractor, bulk trailer-
hand dump. bulk degreening.

5 3I

x 50- %
S0 -

.400 10 20 30

o -
2- S0
5,000 Boxes per Week 10,000 Boxes per Week 15,000 Boxes per Week

Volume per Season (000 Omitted)

Fig. 14.-Effect of volume per season for various weekly volumes upon the average total cost per box for picking,
hauling, receiving and dumping oranges, Florida citrus packinghouses, 1954. All groves within six miles of packinghouse.

Bulk Handling of Fresh Citrus Fruit 31

cally dumping the field boxes after they leave the degreening
room (Fig. 15 and Table 7). The four methods are analyzed in
situations where the citrus groves are within a 30 mile radius
of the packinghouse. If the groves are farther away than 30
miles, the same relative differences in handling cost would be


Volume Cost per Box for Total Seasonal Volume*
per At At At At
Method Week 100,000 200,000 300,000 400,000
Boxes I Boxes Boxes Boxes
I boxes dollars per box

Tractor Basket, 5,000 $0.3102 **
Semitrailer Truck- 10,000 .3486 0.2983 0.2816 t
Bulk Degreening 15,000 .3895 .3181 .2944 0.2824
(Sanford Method)

Goat Truck, Semi- 5,000 0.3748 **
trailer Truck-Hand 10,000 .4303 0.3665 0.3452
Dump, Field Box 15,000 .4890 .3950 .3637 0.3480
(Standard Method I)

Goat Truck Semi- 5,000 0.3594 **
trailer Truck- 10,000 .4054 0.3494 0.3307 t
Automatic Dump, 15,000 .4515 .3724 .3460 0.3328
Bulk Degreening
(Vero Beach Method)

Goat Truck, Semi- 5,000 0.3800 **
trailer Truck- 10,000 .4355 0.3672 0.3444 t
Automatic Dump, 15,000 .4942 .3957 .3629 0.3465
Field Box I
(Standard Method II)

Average total cost per box was calculated by adding average per box fixed cost and
average per box direct cost.
** Maximum volume that can be handled per season when operating at this weekly volume
is slightly in excess of 100,000 boxes.
S Maximum volume that can be handled per season when operating at this weekly volume
is slightly in excess of 300,000 boxes.

The effect of volume per week and of volume per season upon
the average total cost per box for picking, hauling, receiving
and dumping oranges for all four methods is compared in Table
7 and illustrated graphically in Fig. 15. Part A of Fig. 15
illustrates the average cost relationship of the four methods for

C---- Tractor basket, semi-trailer E----- Goat truck, semi-trailer truck,
truck bulk degreening (San- automatic dump, bulk degreening
ford method). (Vero Beach method).
D Goat truck, semi-trailer trucK- F--- Goat truck, semi-trailer truck,
hand dump. automatic dump, field box.

\F F \ \D\F
-\ %%

Z 35 E'. 01 --

0 C

20- 5,000 Boxes per Week 10,000 Boxes per Week 15,000 Boxes per Week

15 L l Il I II
a 0 100 200 300 400 100 200 300 400 100 200 300 400
< Volume per Season (000 omitted)

Fig. 15.-Effect of volume per season for various weekly volumes upon the average total cost per box for picking.
hauling, receiving and dumping oranges, Florida citrus packinghouses, 1954. Majority of groves more than six miles
from packinghouse.

Bulk Handling of Fresh Citrus Fruit 33

a weekly operation of 5,000 boxes. It shows that the Sanford
method costs less than any of the other methods suited to a 30
mile haul. The estimated saving per box in the selection of the
Sanford method for a seasonal volume of 100,000 boxes would
be approximately 5 cents per box over the Vero Beach method,
6.5 cents per box over the field box-semitrailer truck-hand dump
method and approximately 7 cents per box over the semitrailer
truck-automatic dump-field box method.
Parts B and C of Fig. 15 show the cost relationship of the
four methods for 10,000 and 15,000 box-per-week operation.
With this weekly volume the cost relationship between the vari-
ous methods was similar to that found for a 5,000-box weekly
volume. The Sanford method had the lowest cost, the Vero
Beach method had the next lowest cost, and there was very
little difference in cost between the two "standard" methods.
This study includes those costs directly associated with the
picking, hauling, receiving and dumping of the citrus fruit. It
does not include the savings made possible by a more even flow
of fruit through the packinghouse when using the bulk degreen-
ing rooms rather than the conventional hand dumping or auto-
matic dumping methods. These savings were not included in
the calculated cost because, theoretically, hand dumping and
mechanical dumping could be so regulated that the volume of
fruit going over the grading table could be as uniform as when
the fruit is delivered from a bulk degreening room. However,
in the group of packinghouses in which detailed time studies
were made, it was found that neither hand dumping nor me-
chanical dumping kept the flow of fruit going over the grading
table as constant as did the bulk degreening method. An analy-
sis of the observed delays of the graders, lidders, hand truck-
ers, checkers and loaders indicated that there was a saving
of approximately 1 cent per box as a result of the reduction
of nonwork time in favor of the bulk degreening room over the
other methods of dumping citrus.
In addition to the savings made possible by a more uniform
flow of fruit, three other potential savings which are not in-
cluded in the calculated costs are: (1) the advantage of being
able to Dow-hex the fruit shortly after it has been picked, com-
pared to waiting until it has passed through the degreening
process, (2) the savings that may occur by sending fruit to the
cannery plant as "field run" fruit within a few hours after it has
been picked, as compared with sending it as low priced "pack-

34 Florida Agricultural Experiment Stations

inghouse eliminations"; and (3) a reduction in cost of handling
that portion of the fruit that enters the packinghouse but is
immediately presized, graded out and sent to the cannery.
In the course of obtaining the fixed costs of operating the
various systems, a complete analysis of the cost of the bulk
rooms was made. The estimated cost per 1,000 box capacity
was $7,721. This included $2,425 for labor, $1,936 for lumber,
$185 for concrete, and $2,075 for other materials such as press
cloth for baffles. Electrical work was estimated at $335 and
necessary conveyor belts at $765.

A system of bulk handling of fresh fruit for packinghouses
has been developed, three variations of which are being used
commercially. These various systems have been presented and
analyzed. In general they have the following advantages over
the standard system of using field boxes throughout the fresh
fruit operation:
1. Elimination of the field box either partially or entirely.
2. Reduction in labor necessary to handle fruit.
3. Oversized picking bags may used if desired.
4. Under favorable conditions, efficiency of picking crews is
greatly increased.
5. Increased morale and easier working conditions for work-
6. Most of the required labor can be performed by women
if necessary.
7. Increased "effective" capacity of degreening rooms by
prior elimination of rots, splits, over and undersized fruit.
8. Reduction in grade and size variations giving a high per-
centage of packout from degreening room.
9. More even flow of fruit through packinghouse.
10. Higher cannery returns for packinghouse eliminations.
11. Reduction of packinghouse handling charges on fruit
eliminated to cannery.
12. Washing and decay control treatments can be accom-
plished as the fruit enters the packinghouse.
13. Cost analysis shows direct savings of between 61/4 cents
and 11 cents per box over standard methods in addition to
other advantages mentioned.

Bulk Handling of Fresh Citrus Fruit 35

The bulk rooms cost approximately $7,700 per 1,000-box
capacity. For packinghouses where the fruit is received from
a radius of five or six miles the Windermere cart system is
suitable; for packinghouses where fruit is hauled from longer
distances a system employing carts or baskets in the field and
semitrailers to move the fruit into the packinghouse is recom-
Degreening done in bulk rooms is consistently as good as or
better than comparable degreening done in standard rooms.
Damage figures show that fruit handled correctly in bulk is
damaged less than comparable fruit handled in field boxes.

The authors are indebted to the management and personnel of the com-
mercial packinghouses mentioned for their valuable assistance and coopera-
tion. Credit is also due J. C. Bowers and A. H. Rouse, of the Experiment
Station staff, for their work in the early stages and to others assisting in the
various phases of the project. To all these the authors extend their thanks
and appreciation.

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