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Full text of "Precooling rail shipments of Illinois peaches with special reference to the use of ventilated packages"

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I E> R.AR.Y 

OF THL 

U N I VLR.S ITY 
Of ILLINOIS 



6307 

I6b 

no 446-4-57 




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UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN 



L161 O-1096 




Precooliag Rail 
SKipmertts of 



NOIS 




w 



special reference 
to the use 
of ventilated packages 



by 
J.W.Lloyd 




Bulletin 455 

University of Illinois 
Agricultural Experiment Station 




CONTENTS 

PAGE 

PLAN OF THE TESTS 512 

EQUIPMENT USED AND METHOD OF MAKING 

TESTS 512 

RESULTS OF 1935 TESTS: LIMITED TO PRECOOLING 

PERIOD 517 

Ventilated vs. Standard Packages, Both With Standard 

Liners 517 

Ventilated Packages Without Liners vs. Standard Packages 

With Liners 519 

Fruit Loaded on a Cool Day 523 

Fruit Loaded on a Hot Day 523 

RESULTS OF 1937 TESTS: CARS FOLLOWED TO TER- 
MINAL MARKETS 526 

Ventilated vs. Standard Packages Under Standard 

Refrigeration 526 

Ventilated Leigh Tubs vs. Standard Tub Bushels 529 

Ventilated Packages and Liners vs. Standard Packages 

and Liners 532 

Standard vs. Ventilated Round-Bottom Baskets With 

Ventilated Liners 536 

GENERAL DISCUSSION OF RESULTS 540 

COMMERCIAL PRACTICES IN 1938 541 

SUMMARY 542 

CONCLUSIONS 544 

LITERATURE CITED.. .544 



Urbana, Illinois May, 1939 

Publications in the Bulletin series report the results of investigations made by or 
sponsored by the Experiment Station 



PRECOOLING RAIL SHIPMENTS 
OF ILLINOIS PEACHES 

With Special Reference to Use of Ventilated Packages 

J. W. LLOYD, Chief in Fruit and Vegetable Marketing 



TESTS concerned with the refrigeration of eight carloads of 
Illinois peaches four in 1935 and four in 1937 are reported 
in this bulletin. The rapid cooling of peaches in ventilated 
packages had been demonstrated by experiments in 1933 and 1934 
under controlled laboratory conditions, but it seemed advisable to make 
further tests in refrigerator cars in order to determine how well this 
type of package was adapted to carlot shipments. Furthermore it was 
considered desirable to observe the combined effect of forced air circu- 
lation, salt, and ventilated packages on the rapidity with which peaches 
can be cooled after they are loaded into refrigerator cars. 

Earlier experiments by this Station 4 * had shown that in a refrig- 
erator car handled under standard refrigeration the temperature of 
peaches packed in standard bushel baskets and having an initial 
temperature of about 72 F. was reduced about 24 degrees during the 
first 48 hours the car was in transit. In other tests, in which electric 
fans were used to increase the air circulation in refrigerator carloads 
of fruit, there was much greater uniformity of fruit temperatures 
thruout the load and more rapid cooling of the entire lading while 
the fans were in operation. 6 * The addition of salt to the ice in the 
bunkers also hastened refrigeration. 4 * 

In the laboratory tests 5 * referred to above, the most rapid cooling 
took place in ventilated bushel baskets with wide cracks between the 
staves. Peaches packed in this type of ventilated basket without any 
liner cooled down to 50 F. in less than 6 hours, or in less than half the 
time required for the contents of a standard lined tub bushel. Other 
workers 2 * have shown that for safe carriage the temperature of 
peaches should be reduced to 50 F. as quickly as possible. It is reason- 
able to assume that with rapid cooling, peaches could be allowed to 
become more mature and of better flavor before picking. 



The author acknowledges the assistance of S. W. DECKER, M. P. GEHLBACH, 
and V. A. EKSTROM in the procuring of data for this publication. 
*These figures refer to literature citations on page 544. 

511 



512 BULLETIN No. 455 [May, 

PLAN OF THE TESTS 

Plans for conducting the tests reported herein were started during 
the 1935 Illinois peach shipping season, and arrangements were made 
with one of the package manufacturers to make up a special order of 
ventilated packages for use in the tests, since baskets of this type were 
not carried in stock at that time. 

Before fans for this work had been procured, it was learned that 
two different companies operating precooling equipment were seeking 
business at Illinois peach shipping points. Contacts were made with 
shippers considering the use of this service, and arrangements were 
finally made to conduct tests with a number of carloads. In each test, 
one half (one end) of the car was loaded with peaches packed in 
ventilated baskets and the other half with peaches packed in standard 
tub bushel baskets or standard round-bottom bushel baskets. Previous 
tests had shown that refrigeration is practically the same at similar 
points in opposite ends of refrigerator cars, provided lading, package 
types, and loading system are similar in the two ends of the car. 4 * 

Tests were undertaken in a number of cars in 1935, but various 
contingencies arose which rendered the results in several of the cars 
unreliable, such as failure of the fans to work properly, unloading part 
of car to fill truck orders, exhaustion of a large part of the ice supply 
in bunkers before the precooling period was completed, and unusual 
delay in completing loading of car. Therefore only four cars included 
in the tests made in 1935 are reported herein. 

The Illinois peach crop in 1936 was too limited in volume to war- 
rant undertaking any commercial precooling tests. In 1937 tests were 
resumed. These included only four cars, but in each test the car was 
followed thru to the terminal market. Temperature readings were 
made enroute and the fruit was inspected upon arrival. Results of the 
tests on the four cars in 1935 and the four cars in 1937 are included in 
the present report. 

The Elberta variety was used in the 1935 tests. In 1937 three cars 
were loaded with Elberta and one with the Red Bird variety. 

EQUIPMENT USED AND METHOD OF MAKING TESTS 

Precooling Equipment. The equipment of the two companies fur- 
nishing the precooling service used in these tests was entirely different. 
One type consisted of electric fans approximately 18 inches in diameter 
mounted on motors to be connected with the power-and-light circuit at 
the packing shed. One fan was placed at each end of the car directly 



1939] 



PRECOOLINC. ILLINOIS PEACHES 



513 




FIG. 1. ELECTRIC FAN IN POSITION AT END OF CAR 

Precooling by means of this type of equipment involves the use of salt with 
the ice in the bunkers. 



opposite the center of the opening between the body of the car and 
the top of the ice bunker (Fig. 1). A baffle of fabricated wood covered 
with canvas closed all the opening at the top of the bunker except the 
portion occupied by the fan. 

The fans used in different tests with this first type of precooling 
equipment differed somewhat in type, some being multiple-bladed and 
others single-bladed. One of the most satisfactory was a single-bladed 
propeller fan with a half-horsepower motor, rated at 3450 r.p.m. This 
was operated on 220 volts, alternating current. Each fan was set so as 
to draw the cold air out of the top of the ice bunker and force it down 
upon the load and toward the center of the car. Thus air currents 
were set up which were directly opposite to those which normally occur 
in a refrigerator car loaded with fruit. 6 * Of course the velocity of the 
air currents generated by the fans was very much greater than the 
ordinary rate of air movement in a refrigerator car. 

When operating the above type of precooling equipment, salt was 
added to the ice in the bunkers after the loading of the car with fruit 
was completed and usually just before the fans were started. Some- 
times more salt was added later. 



514 



BULLETIN No. 455 



[May, 



The other type of precooling equipment employed was much more 
elaborate. Each precooling unit was self-contained and furnished its 
own power. It was mounted on a motor truck chassis and could be 
parked beside a refrigerator car on any team track and put into opera- 
tion, all power required being furnished by the truck motor (Fig. 2). 
When this machine was used, the ice in the bunkers had no relation to 
the cooling of the fruit. The portable refrigeration plant itself fur- 




* 



FIG. 2. PORTABLE PRECOOLING PLANT MOUNTED ON TRUCK CHASSIS 
The truck motor furnishes the power for operating this refrigeration plant, 
which can be parked beside a refrigerator car on any team track. 



nished the cold air which was forced into the car above the load thru 
the upper part of the doorway at one side of the car. After circu- 
lating thru the load it was drawn back into the machine thru an open- 
ing near the bottom of the false door that was fitted into the doorway 
of the car. A heavy canvas, perforated in certain areas, covered the 
center part of the load to aid in forcing the cold air toward the ends 
of the car. 

Types of Packages and Liners. The ventilated packages used in 
the 1935 tests were round-bottom bushel baskets each having 20 cracks 
approximately %-inch wide at the top and gradually tapering until at 
the bottom the basket was solid (Fig. 3). These were compared with 
standard tub bushels or with standard round-bottom bushel baskets in 
the different tests. Paper liners were used with both ventilated and 
standard packages in all except one of the tests made in 1935. Each 
liner used in 1935 had 21 round holes {Y\ inch) arranged in two rows 
located at one- fourth the distance from the top and from the bottom. 

In 1937 ventilated Leigh tubs (Fig. 4) were used as the ventilated 



1939] 



PRECOOLING ILLINOIS PEACHES 



515 




FIG. 3. VENTILATED ROUND-BOTTOM BASKET (left) AND 

STANDARD TUB BUSHEL (right) 

The three-hoop ventilated basket shown here is a more rigid package than 
the two-hoop ventilated basket, which was used in all but one of the tests in 
which round-bottom baskets were employed. 




FIG. 4. VENTILATED LEIGH TUB (left) AND VENTILATED TUB 

BUSHEL (right) USED IN TESTS 

These two packages were quite extensively used for shipping Illinois 
peaches in 1938. 




FIG. 5. Two TYPES OF LINERS USED IN 1937 TESTS 

The new type of ventilated liner (left), with 80 holes, was used in all of the 
1937 tests. It is a vast improvement over liners with 21 or 18 holes (right) which 
were in common use commercially in 1937 and were used in the 1935 tests. 



516 BULLETIN No. 455 [May, 

package in two of the tests, ventilated tub bushels in the third, and 
ventilated round-bottom baskets in the fourth. In 1937 a new type 
of liner was used which provided more thoro ventilation than any 
available in 1935. The new liner contained 80 holes, each H/^ inches 
long and 1/2 inch wide (Fig. 5). Some of the standard liners in general 
use in 1937 contained only 18 holes, and these were not very well 
distributed (Fig. 5). 

Equipment for Determining Temperatures. Sixteen thermocouples 
were used in each car in 1935. Four were placed in the air and 12 were 
inserted in the fruit. Positions of the thermocouples in cars precooled 
with the fan type of equipment are indicated in Fig. 6. When the 



THERMOCOUPLES 

T/ 




T* Aft A A K A A A * A A A A A JTl 



FIG. 6. POSITIONS OF THERMOCOUPLES IN TEST CARS PRECOOLED WITH 

FAN TYPE OF EQUIPMENT IN 1935 

Twelve thermocouples were inserted in the fruit, while 4 recorded air 
temperatures. 



T HER MOM E TERS 




FIG. 7. POSITIONS OF THERMOMETERS IN TEST CARS IN 1937 
Eight thermometers indicated temperatures of the fruit in different parts of 
the car, while 4 indicated air temperatures. 

truck type of precooler was used thermocouples were placed to record 
the temperature of the air as it entered the car and as it left, instead of 
recording the temperature at the bottom of the ice bunkers. 

In placing a thermocouple in a fruit, the point was inserted in such 
a way that it grazed the side of the fruit pit and then passed a short 
distance into the flesh. Under this arrangement the temperature read- 
ings were those of the flesh in the immediate vicinity of the pit. In each 
instance the thermocouple was inserted in a fruit as near the center of 



1939] PRECOOLING ILLINOIS PEACHES 517 

the package as was expedient ; usually the fruit selected was in the third 
layer from the top, and in the third ring or center fruit of that layer. 

For determining the temperatures in 1937, electrical resistance 
thermometers were employed except in one of the tests. Twelve 
thermometers were used in each car, 4 in the air and 8 in the fruit, at 
positions indicated in Fig. 7. The same method of inserting the 
thermometer points in the fruit was employed as with the thermo- 
couples, and the position of the selected fruit in the package was 
essentially the same. The baskets of fruit in which temperatures were 
taken were always in the third row from one side of the car. 

Arrangement of Packages in Car. All cars of peaches were loaded 
3 packages high, 6 wide, and 21 to 22 long, depending upon the length 
of the car. 

RESULTS OF 1935 TESTS: LIMITED TO 
PRECOOLING PERIOD 

Ventilated vs. Standard Packages, Both With Standard Liners 

In Car A, loaded at Ozark, Illinois, August 10, 1935, a comparison 
was made between the rate of cooling of peaches packed in standard 
tub bushels and in ventilated round-bottom baskets, both equipped 
with standard liners and facing pads. The fan type of precooler was 
used. Two hundred pounds of salt was added to the ice just before the 
fans were started. After the fans had been operating 1 14 hours, 2,000 
pounds of ice and 100 pounds more of salt were placed in the bunkers, 
which were not as well filled with ice as they should have been at the 
time precooling started. The fans were shut off for 15 minutes during 
this icing and salting. Operation was continued for 81/2 hours from the 
start, except for the 15 minute shut-off, mentioned above, and another 
shut-off of 30 minutes to allow a switch engine to move the car 6^i 
hours after the start. 

Rapidity of Cooling. Temperature readings were taken ten times 
during the test. The readings for the fruit in each type of package are 
given in Table 1, together with the total drop in temperature during the 
8y-hour period, and the air temperature at lower bunker openings and 
above the load. 

The 15-minute shut-off of the fans and opening of the bunkers for 
reicing after the precooling equipment had been operating for 1}4 hours 
seriously interfered with the progress of the precooling. Every ther- 
mometer in the car registered higher at the end of the second hour 
than at the end of the first hour. Shutting off the fans toward the 



518 



BULLETIN No. 455 



[May, 



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1939] 



PRECOOLING ILLINOIS PEACHES 



519 



end of the precooling period, while the car was being switched, did not 
affect the temperature so much. 

The cooling of the fruit was distinctly more rapid in the ventilated 
packages and in the top layer of packages of both types. The more 
rapid cooling of the top layer, compared with the bottom layer, was 
due to the reversal of the air currents in the car while the fans were 




50 



FIG. 8. PROGRESS OF COOLING OF PEACHES IN STANDARD AND IN 

VENTILATED PACKAGES IN CAR A 

Cooling was distinctly more rapid in the ventilated packages. Standard 
liners and facing pads were used in both types of packages, and the fan type 
of precooler was used. 



operating. If the temperature reductions in the baskets in both layers 
are averaged, the fruit in the ventilated packages shows a decline of 
25.8 degrees and that in the standard packages only 18.4 degrees. The 
progress of the cooling in the two types of packages is shown in Fig. 8. 

Ventilated Packages Without Liners vs. Standard 
Packages With Liners 

In Car B, tested at Kinmundy, Illinois, August 29, 1935, a com- 
parison was made between the rate of cooling of peaches packed in 
standard round-bottom baskets with standard liners and those packed 
in ventilated round-bottom baskets without any liners. The fan type of 
precooling equipment was used. Two hundred pounds of salt was 



520 



BULLETIN No. 455 



[May, 



added to the ice in the bunkers just before the fans were started. No 
additional salt was used. The fans were operated without interruption 
for 6 hours. 

Marked Differences in Rapidity of Cooling. Because of the cool 
weather prevailing when the peaches loaded in this car were harvested, 
the temperature of the fruit at the time precooling started was much 
lower than in Car A. Hence the rate of cooling was slower. 5 * However, 



70 




FIG. 9. RAPIDITY OF COOLING OF PEACHES IN UNLINED VENTILATED BASKETS 

AND IN LINED STANDARD BASKETS IN CAR B 

The difference in rate of cooling in the two types of packages was un- 
doubtedly accentuated by the absence of liners in the ventilated baskets. The fan 
type of precooler was used. 



the difference in rate of cooling in the standard baskets and the venti- 
lated baskets was extremely marked, the average drop in temperature 
of the fruit in the ventilated baskets being nearly three times as great 
as that of the fruit in the standard baskets (15.7 F. against 5.7). 
Here again the temperature of the fruit in the top layer of packages 
was reduced more rapidly than that of the fruit in the lower layer 
(Table 2). 

The difference in temperature drop in the two kinds of packages 
was undoubtedly accentuated by the absence of any liners in the 
ventilated packages, the circulating cold air thus having freer access 
to the fruit in those packages. 5 * The temperature of the fruit in both 
top and bottom layers of the ventilated packages was reduced to a safe 
carrying degree within the 6-hour precooling period. The relative 
rapidity of cooling of fruit in the two types of packages is indicated in 
Fig. 9. 



PRECOOLING ILLINOIS PEACHES 



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1939] 



PRECOOLING ILLINOIS PEACHES 



Fruit Loaded on a Cool Day 



523 



The portable type of precooling plant mounted on a truck chassis 
was used for precooling Car C, loaded at Cobden, Illinois, August 13, 
1935. The day the fruit was harvested and packed the weather was 
cloudy and fairly cool, so that the temperatures of the fruit at time of 
loading were not very high. The precooler was operated only 21/4 
hours, in accordance with the commercial practice of the company. 
Temperature readings were continued for an hour after the precooler 
was disconnected from the car. 

Portable Precooler Was Effective. During the hour after the pre- 
cooler was detached, the temperatures of the fruit near the center of 
the baskets continued to decrease rapidly on account of the transfer 




50 



FIG. 10. COOLING OF PEACHES LOADED ON A COOL DAY, CAR C 
The portable type of precooling plant used on this load rapidly reduced 
the temperature of the fruit in both types of packages, tho the fruit in the 
ventilated baskets cooled considerably faster than in the standard baskets. Both 
types of baskets were equipped with standard liners. 



of heat between the different rows of fruit in the package. 5 * During 
the 3}4-hour cooling period the average drop in temperature of the 
fruit in the standard tub bushel baskets was 11.9 degrees, while in the 
ventilated round-bottom baskets it was 16.1 degrees (Table 3 and 
Fig. 10). Standard liners were used in both types of package. 

Fruit Loaded on a Hot Day 

Car D, tested at Cobden, Illinois, August 16, 1935, was loaded 
with fruit packed during a day when the temperature was high, the 



524 



BULLETIN No. 455 





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1939] 



PRECOOLING ILLINOIS PEACHES 



525 



outside thermometer registering 94 F. at 4 p. m., the time at which the 
loading was completed. A temperature reading was made at this time, 
but the precooling machine, which was of the same type as that used 
for Car C, did not start operating until 4:45. The next reading was 
made at 5 p. m., after the machine had been operating for 15 minutes. 
No reading was made just before the machine started. 

After the loading had been completed and the car closed, and 
previous to the starting of the machine, the refrigerative effect of the 
ice in the bunkers was operative for y\ hour. The precooler was 
operated for 2i/4 hours. Thus a total of 3 hours elapsed from the time 
the first reading was made until just before the precooler was stopped. 
Temperature readings were continued for 1^4 hours after the pre- 
cooling machine was detached from the car, making a total period of 
hours during which temperature records were taken. 




60 



FIG. 11. COOLING OF PEACHES LOADED ON A HOT DAY, CAR D 
Fruit at high initial temperature was cooled very rapidly by the portable 
type of precooling plant, but this was especially true of the fruit in the venti- 
lated packages. Standard liners were used in both types of packages. 



Marked Differences Between Packages. Again, the fruit in the 
ventilated packages cooled much more rapidly than that in the standard 
packages, the difference in rate of cooling being somewhat more marked 
than in Car C. This greater difference may have been due to the higher 
initial temperature of the fruit in Car D. The average drop in the 
temperature of the fruit in the standard tub bushel baskets during the 
4^4 hours was 12.7 degrees, while that of the fruit in the ventilated 
round-bottom bushel baskets was 21.1 degrees (Table 4 and Fig. 11). 
Both types of packages were equipped with standard liners. 



526 BULLETIN No. 455 [May, 

RESULTS OF 1937 TESTS: CARS FOLLOWED TO 
TERMINAL MARKETS 

In the tests conducted in 1935 there was no opportunity for 
determining the ultimate effect of the precooling, either by temperature 
readings while the fruit was in transit or by inspection of the fruit upon 
arrival at destination. Plans for the tests in 1937 therefore provided 
for following each car, taking temperature readings at transfer and 
reicing stations, and inspecting the condition of the fruit when the 
car was opened in the terminal market to which it was shipped. Cars 
were purposely selected that were to be billed to points at considerable 
distance, so that the real effect of differences in temperature of fruit 
at the end of the precooling period might have a chance to manifest 
itself. 

In the 1937 tests fruit temperatures were determined at eight points 
in each car (Fig. 7). 

Since practically a week's time is required to prepare a test car, 
conduct the precooling operations, follow the car thru to market, await 
the unloading of the car so the temperature-recording equipment could 
be taken out, and drive back to the producing region, it was decided to 
make one test on Red Bird peaches before the opening of the Elberta 
shipping season, so as to run at least four tests while Illinois peaches 
were available. 

As a result of the favorable outcome of the tests of ventilated 
packages in 1935 (a preliminary report of which was presented at the 
meeting of the Illinois State Horticultural Society in December of that 
year 3 *), several peach growers in the state had provided themselves 
with ventilated packages for part of their shipments in 1937. Arrange- 
ments were made with certain of these growers for conducting tests on 
some of their cars. The orchardist with whom arrangements were 
made for testing the car of Red Bird peaches and one car of Elbertas 
had provided himself with a supply of ventilated Leigh tubs (Fig. 4), 
which he expected to use for shipping most of his fruit. Accordingly 
these Leigh tubs were used as the ventilated package for comparison 
with standard tub bushel baskets. A new type of ventilated liner, 
commercially available in 1937 (Fig. 5), was used in both types of 
package in the test with Red Bird peaches. 

Ventilated vs. Standard Packages Under Standard Refrigeration 

Car E, loaded with Red Bird peaches at Cobden, Illinois, on July 5, 
1937, was followed thru to Detroit, Michigan. Since no precooling 



1939] PRECOOLING ILLINOIS PEACHES 527 

TABLE 5. PROGRESS OF COOLING OF RED BIRD PEACHES IN STANDARD AND IN 

VENTILATED PACKAGES IN DIFFERENT LOCATIONS IN CAR E, 1937 

(Car was shipped from Cobden, Illinois, to Detroit, Michigan, under standard 

refrigeration without precooling. Eighty-hole liners were used in all packages) 



Time elapsed (hours) 


Start 


2X 


Chicago 
22 


Detroit Drop in 
44 K 2^ hrs. 


Drop in 
22 hrs. 


Standard tub 


(Temperature of fruit, F.) 


Lower layer 














Basket 2 


. 66.0 


65.4 


59.9 


54.0 


.6 


6.1 


Basket 8 


. . 75.4 


71.6 


61.8 




3.8 


13.6 


Average 


. . 70.7 


68.5 


60.8 




2.2 


9.8 


Top layer 














Basket 2 


. 65.7 


64.2 


57.1 


53.4 


1.5 


8.6 


Basket 8 


.. 72.9 


72.6 


59.9 


57.1 


.3 


13.0 


Average 


. . 69.3 


68.4 


58.5 


55.2 


.9 


10.8 


Average, both layers 


. . 70.0 


68.4 


59.7 


54.8 


1.5 


10.3 


Ventilated (Leigh) tub 














Lower layer 














Basket 2 


76.0 


58.3 


42.0 


40.1 


17.7 


34.0 


Basket 8 


. . 89.8 


77.8 


57.4 




12.0 


32.4 


Average 


. . 82.9 


68.0 


49.7 




14.9 


33.2 


Top layer 














Basket 2 


. 83.4 


81.6 


52.1 


49.7 


1.8 


31.3 


Basket 8 


. . 84.6 


81.6 


59.9 


56.5 


3.0 


24.7 


Average 


.. 84.0 


81.6 


56.0 


53.1 


2.4 


28.0 


Average, both layers 


. . 83.4 


74.8 


52.8 


48.8 


8.6 


30.6 


(Temperature of air) 


At bottom of bunker, standard .... 


. 52.8 


43.8 


35.7 


35.7 






At bottom of bunker, ventilated . . . 


.. 51.5 


42.0 


35.7 


36.0 






Above load, 1 standard 


.. 71.9 


68.0 


56.5 


55.6 


. . 




Above load, 1 ventilated 


71.3 


60.8 


51.2 


50.6 







Fifteen inches above load, 3 feet from bunker. 

equipment was available at Cobden before the beginning of the Elberta 
season, the car was shipped under standard refrigeration without pre- 
cooling. Both standard and ventilated packages were used. 

Temperature readings were made soon after the car was closed 
following the completion of the loading. Another reading was made 
2^2 hours later, shortly before the car left the shipping point. The 
next reading was made in Chicago 22 hours after the original reading; 
and the final reading was made in Detroit 44^ hours after the first 
reading (Table 5). 

Temperature Reductions Previous to Shipment. Owing to differ- 
ence in time of loading, the temperature of the fruit in the standard 
packages was much lower than of that in the ventilated packages at the 
time the first reading was made. During the first 2i/i hours of refriger- 
ation the drop in the temperature of the fruit in the standard packages 
was slightly more than 2 degrees in the lower layer of baskets and 
slightly less than 1 degree in the top layer. The drop in temperature 
of the fruit in the ventilated packages during this 2i/2-hour period was 
14.9 degrees in the lower layer and 2.4 degrees in the top layer. This 
shows the rapidity with which refrigeration may start in the ventilated 



528 



BULLETIN No. 455 



[May, 



packages in the lower layer directly accessible to the cold air emerging 
from the bottom of the bunker and drifting toward the center of 
the car. 

Temperature Reductions in Transit. The further influence of the 
two types of packages upon rate of refrigeration is well indicated by 
the reduction in temperature during the 22-hour period which elapsed 
by the time the car reached Chicago. The average drop in temperature 
of the fruit in the lower layer of standard packages during the period 
was 9.8 degrees, while that in the top layer was 10.8 degrees, or an 
average of 10.3 degrees for both layers. The drop in temperature of 
the fruit in the lower layer of ventilated packages during the same 
period was 33.2 degrees, while that in the top layer was 28.0 degrees, 
or an average of 30.6 degrees for both layers. Altho the average 
temperature of the fruit in the ventilated packages at the start was 
13.4 degrees higher than that of the fruit in the standard packages, it 
was 6.9 degrees lower at the end of the 22-hour period (Fig. 12). 
Even tho allowance is made for the differences in temperature at the 
start, there is a wide margin in favor of the ventilated packages in 
reference to rapidity of refrigeration of the fruit contained. 




40 



FIG. 12. COOLING OF PEACHES IN STANDARD AND IN VENTILATED 

PACKAGES UNDER STANDARD REFRIGERATION, CAR E 

This car was shipped from Cobden, Illinois, to Detroit, Michigan, without 
precooling. Refrigeration was much more rapid in the ventilated packages. 
Eighty-hole liners were used in both types of packages. 



1939] PRECOOLING ILLINOIS PEACHES 529 

Temperature and Condition of Fruit at Destination. By the time 
the car reached Detroit one thermometer had become displaced. Leav- 
ing out of consideration the corresponding thermometer in the other 
end of the car, the average temperature of the three baskets of fruit 
in the standard packages was 54.8 F., while that in the ventilated 
packages was 48.8 F., a difference of 6 degrees. 

Inspection in Detroit 44i/i hours after the car was loaded at Cobden 
showed the U. S. No. 1 peaches to be in good firm condition except 
for a trace (about 1 percent) of brown rot in the fruit in the standard 
packages. There was no decay apparent in the No. 1 peaches in the 
ventilated packages. A few baskets of Utility grade peaches in venti- 
lated packages, that had been put in to fill out the car, showed 7 per- 
cent brown rot. 

Ventilated Leigh Tubs vs. Standard Tub Bushels 

Car F, loaded with Elberta peaches at Cobden, Illinois, on August 
13, 1937, was precooled and billed thru to Bay City, Michigan. The 
precooling was done with the portable truck type of precooler. The 
peaches in one half of the car were packed in ventilated Leigh tubs 
while those in the other end were packed in standard bushel tubs. The 
new type of ventilated liner, with 80 holes, was used in both types of 
packages. The condition of the fruit in both types of containers was 
"hard" to "firm" at the time of loading. Loading was completed and 
the car closed at 11:40 a. m. The bunkers were practically full of ice 
at this time. A temperature reading was made at 1 p. m., and the car 
was opened for attaching the precooling equipment at 1:10. Actual 
precooling was started a few minutes later, and the machine was con- 
tinued in operation for 3 hours. 

Temperatures During Precooling. During the 3-hour precooling 
period the temperature of the peaches in the standard packages near 
the center of the car dropped very rapidly (18 degrees in the lower 
layer and 25 degrees in the top layer). The drop in temperature of 
the fruit in the same type of packages near the end of the car was 
very much less (7.8 degrees and 9.2 degrees in lower and top layers 
respectively). On the other hand there was much less variation in the 
amount of drop in temperature of the fruit in ventilated packages in 
different positions in the car. In the lower layer the difference in 
temperature of the fruit in the package near the end of the car and 
near the center was only 2i/2 degrees. In the top layer the difference 
was greater, the drop being 20 degrees in the basket near the center 
of the car and 12.2 degrees in the basket near the end of the car. 



530 



BULLETIN No. 455 



[May, 



There was thus much better distribution of the refrigeration in the 
ventilated packages, even tho the average drop in temperature was only 
slightly greater (Table 6). 

Temperatures in Transit. Half an hour after the above readings 
were made, the car was "pulled" by a switch engine and attached to the 
fast fruit train. The bunkers were seven-eighths full of ice at this 
time. The car was billed for Bay City, Michigan, with instructions 
not to reice. 

The next temperature reading was made in Chicago 22 hours after 
the initial reading. By this time the temperature of the fruit in the 
standard containers in different parts of the car was much more nearly 
equalized. 

Temperature readings were made at Grand Rapids, at Saginaw 
(two readings), and finally at Bay City 68 hours after the original 
reading at Cobden. The drop in the temperature of the fruit in the two 
types of packages during the first 48 hours is shown graphically in 
Fig. 13. 



90 




42 



FIG. 13. COOLING OF PEACHES IN STANDARD AND IN VENTILATED 

PACKAGES IN CAR F, PRECOOLED BUT Nor REICED 

This car was precooled and billed thru to Bay City, Michigan, without 
reicing. It was in transit for 68 hours. The temperatures during the first 48 
hours of the 68 in which the car was in transit are shown here. Temperatures 
of fruit in different parts of the car and in the two types of packages tended 
to become equalized as the end of the journey approached. Eighty-hole liners 
were used in both types of packages. 



PRECOOLING ILLINOIS PEACHES 



531 






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532 



BULLETIN No. 455 



[May, 



Temperatures at Destination. When the car arrived at its destina- 
tion, the bunkers were nearly half full of ice, and there was no apparent 
difference in the amount of ice in the two bunkers. The temperature 
of the fruit in the top layer of packages was nearly uniform thruout 
the length of the car, including both types of packages. The tempera- 
ture of the fruit in the lower layer of packages was, for each type of 
package distinctly lower than that in the top layer. The average 
temperature of the fruit in the ventilated packages was only slightly 
lower (1^/2 degrees) than that of the fruit in the standard containers. 

Condition of Fruit at Destination. Within a few minutes after the 
temperature reading in Bay City, the car was opened and about one- 
third of the peaches were unloaded. The peaches were firm and in good 
market condition at this time with the exception of a very small per- 
centage that showed rot. The fruits from one package of each type 
of container taken from corresponding positions in the car were 



TABLE 7. DEFECTIVE PEACHES IN STANDARD AND IN VENTILATED CONTAINERS 
ON ARRIVAL IN MARKET AT BAY CITY, MICHIGAN: CAR F 



Kind of package 


Number of 
fruit in 
package 


Brown rot 


Bruised peaches 


Standard tub bushel 


178 
198 


No. 
3 

1 


perct. 
1.68 

.50 


No. 
6 

4 


perct. 
3.37 

2.02 


Ventilated (Leigh) tub 





counted out and very carefully examined. Of the 178 peaches in the 
standard container 3 showed brown rot and 6 showed shipping bruises. 
Of the 198 peaches in the ventilated package only 1 showed brown rot 
while 4 showed shipping bruises (Table 7). Altho the percentage of 
damaged peaches was small, there appeared to be some advantage in 
favor of the fruit shipped in the ventilated packages. 

Ventilated Packages and Liners vs. Standard Packages and Liners 

Car G was loaded with Elberta peaches at Ozark, Illinois, on 
August 20, 1937, and precooled with the fan type of precooling equip- 
ment. One half of the car was loaded with peaches packed in venti- 
lated tub bushels and the other half with peaches packed in standard 
tub bushels. The new type of ventilated liner was used in the venti- 
lated containers, and the old type of liner (with much less ventilation) 
was used in the standard containers. 

Loading was started at 12 m. and was completed at 2:45 p. m. The 



1939] PRECOOLING ILLINOIS PEACHES 533 

car had been fully iced before it was received at the siding, but more 
ice was added at 12:30 p. m. to completely fill the bunkers. The car 
was closed at 2:50 p. m. and the precooling equipment was put into 
operation at 2:52. At 3:30 p. m. the ice bunkers were opened and 200 
pounds of salt was placed over the ice and chopped in. Precooling was 
continued until 7:50, a total period of 5 hours. The equipment was 
removed and the car sealed at 8 p. m. 

This car was billed out under standard refrigeration for Buffalo, 
New York. Temperature readings were made at Bluford and Neoga, 
Illinois; at Frankfort, Indiana; Bellevue, Ohio; and finally at the Food 
Terminal in Buffalo, New York. 

Reicing took place at Bluford, Frankfort, and Bellevue. The 
elapsed time from the start of precooling until delivery of the car at 
its destination was 63 hours. 

Drop in Temperatures During Precooling. At the time precooling 
started, the average temperature of the fruit in the ventilated tubs was 
3.3 degrees higher than that of the fruit in the standard tubs. At the 
end of the 5-hour precooling period the average temperature of the 
fruit in the ventilated tubs was 12.3 degrees lower than that of the 
fruit in the standard tubs. In the bottom layer cooling was more rapid 
in the package near the bunker than in that toward the center of the 
car in both types of package. In the top layer cooling was about equally 
rapid in the standard containers in both positions, but was more rapid 
in the ventilated package toward the center of the car (Table 8). 

Temperatures in Transit and at Destination. When the reading 
was made at Bluford 21 1/2 hours after the loading had been completed, 
the difference in temperature of the fruit in the two types of packages 
was less marked than at the close of the precooling period. At this 
time the average temperature of the fruit in the ventilated packages 
was 52.5 F., while that of the fruit in the standard packages was 56.7 
F. The temperature of the fruit in both types of packages continued 
to decline until the car was delivered at its destination, when the aver- 
age temperature of the fruit in the ventilated packages was 44.0 F. 
and that of the fruit in the standard packages was 46.0 F. 

The progress of cooling of the fruit in each type of package during 
the first 48 hours is graphically presented in Fig. 14. 

Condition of Fruit at Destination. The peaches were inspected 
upon arrival by two inspectors, one a representative of the consignee 
and the other a representative of the railway company. Fifty peaches 
were taken out of each basket inspected. All inspected baskets were 
from the top layer in the car. Results of the inspection are shown in 



534 



BULLETIN No. 455 



[May, 



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1939] 



PRECOOLING ILLINOIS PEACHES 



535 



Table 9. Both inspectors stated that the fruit seemed to be in a little 
better condition in the ventilated packages. The amount of brown rot 
or of "decay" was too small to warrant any definite comparisons on 
these points. Likewise, there was little difference in the percentage of 
"soft" peaches in the two types of packages. 




40 



42 



FIG. 14. COOLING OF PEACHES IN STANDARD AND IN VENTILATED 

PACKAGES IN CAR G DURING FIRST 48 HOURS 

This car was followed thru to Buffalo, New York, which was reached in 
63 hours. Undoubtedly the new type of liner was an important factor in the 
extremely rapid refrigeration of the fruit which took place in the ventilated 
packages during the precooling period. An 18-hole liner was used with the 
standard packages. 



TABLE 9. DEFECTIVE PEACHES IN STANDARD AND IN VENTILATED CONTAINERS 
ON ARRIVAL IN MARKET AT BUFFALO, NEW YORK: CAR G 



Kind of package 
and position 


Brown rot 


"Decay" 


Soft peaches 


Standard tub 
4th from end 


No. 
1 
None 
None 

1 

None 
None 
None 
None 
None 


pent. 
.66 

None 


No. 
None 
None 
None 
None 

None 
None 
2 
None 
2 


perct. 
None 

1.00 


No. 
2 
None 
2 
4 

1 

5 
None 
None 
6 


perct. 
2.66 

3.00 


At Quarter-length 


Near middle of car. . . . 


All 3 baskets 


Ventilated tub 
3d from end 


At quarter-length 


Near bunker 


Near middle of car . 


All 4 baskets 





536 BULLETIN No. 455 [May, 

Standard vs. Ventilated Round-Bottom Baskets 
With Ventilated Liners 

Car H, loaded with Elberta peaches at a siding near Irvington, 
Illinois, on August 27, 1937, was followed thru to its destination in 
Burlington, Vermont. Half the car was loaded with peaches packed in 
standard round-bottom bushel baskets and half with peaches packed 
in ventilated round-bottom baskets. The new type of ventilated liner 
was used in both types of packages. The bunkers were completely 
full of ice when loading of the car started at 2:30 p. m. The first 
reading was made at 5 p. m. after the thermometers had been in place 
about half an hour. The car was switched from the loading track to the 
Centralia ice yard, and arrived at the ice track at 9:45 p. m. A tempera- 
ture reading was made just before the car was opened at 10 p. m. to 
install the precooling equipment, which was of the fan type. Ice was 
added at 10: 15 p. m., in the amount of 3,200 pounds, to fill the bunkers ; 
and 200 pounds of salt was placed on top of the ice. 

The precooler was started into operation at 10:30 p. m. and was 
continued in operation until 4:30 a. m., a period of 6 hours, during 
which readings were made once an hour. 

Average Temperature Reduction Previous to Shipment.- During 
the 5 hours after the first temperature reading was made and before the 
salt was put in or the fans were started, the average drop in tempera- 
ture of the fruit in the standard baskets was 6.3 degrees while that of 
the fruit in the ventilated baskets was 9.3 degrees even tho the tempera- 
ture in the ventilated baskets at the start was 5.9 degrees lower than 
in the standard baskets. During the 6 hours the precooler was in 
operation the average temperature of the fruit in the standard baskets 
was reduced 13.7 degrees and that of the fruit in the ventilated baskets 
16.1 degrees. 

During the 11 hours after loading and previous to shipping, the 
average temperature of the fruit in the standard baskets was reduced 
20 degrees and that of the fruit in the ventilated baskets 25.5 degrees, 
thus increasing the difference in temperature between the two lots to 
11.4 degrees, and leaving the average temperature of the fruit in the 
standard baskets at 65.2 F. and that of the fruit in the ventilated 
packages at 53.8 F. at the close of the precooling period (Table 10). 

Temperature Reductions in Different Layers. During the first 5 
hours, while the normal cooling effect of the ice in the bunkers without 
forced air circulation or salt was operative, the fruit in the lower layer 
of packages cooled more rapidly than that in the top layer of the same 
type of package. As soon as the precooling equipment was put into 



1939] 



PRECOOLING ILLINOIS PEACHES 



537 



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I i 



BULLETIN No. 455 



[May, 




HOURS 

FIG. 15. COOLING OF PEACHES IN TOP AND BOTTOM LAYERS OF 

PACKAGES IN CAR H DURING FIRST 11 HOURS 

Cooling was much accelerated when the precooling equipment started opera- 
tion 5 hours after loading. Immediate change in rate of cooling of fruit in the 
top layer of packages was apparent. The new type of 80-hole liner was used in 
both types of packages. 



operation, the temperature of the fruit in the top layer began to drop 
more rapidly than that of the fruit in the lower layer, and the more 
rapid cooling of the top layer was maintained to the end of the pre- 
cooling period (Fig. 15). This illustrates the point that precooling by 
forcing a blast of cold air over the top of the load of fruit reduces the 
temperature of the fruit which is normally the hottest and least affected 
by the normal flow of cold air from the bottom of the ice bunkers. 
Thus more uniform refrigeration thruout the load of fruit is eventually 
effected. 

Treatment of Car in Transit. The precooling equipment was 
removed and the car sealed at 4:45 a. m., August 28. At 5:30 a. m. 
the bunkers were again filled with ice, 2,800 pounds being used. The 
car was billed out under standard refrigeration to Burlington, Vermont. 
It was reiced at Harvey, Illinois; Port Huron, Michigan; and St. 
Albans, Vermont. Temperature readings were made at Champaign 
and Harvey, Illinois; at Port Huron, Michigan; Mimico, Ontario; 
and upon arrival at Burlington, Vermont. 

Temperature Reductions in Transit. The reading in Champaign 
was made 28 hours after the initial reading at the loading point. At 



PRECOOLING ILLINOIS PEACHES 




40 



FIG. 16. COOLING OF PEACHES IN STANDARD AND IN VENTILATED 

PACKAGES IN CAR H DURING FIRST 48 HOURS 

Precooled and shipped under standard refrigeration to Burlington, Vermont, 
this car reached its destination 91 1/2 hours after the initial temperature reading. 
The fruit arrived in firm condition. The 80-hole ventilated type of liner was 
used in both types of packages. 



this time the average temperature of the fruit in the standard baskets 
had been reduced to 53.4 F. and that of the fruit in the ventilated 
baskets to 48.0 F. In the reading at Port Huron 48 hours after the 
original reading, the average temperature of the fruit in the standard 
baskets was found to be 47.4 F. and that of the fruit in the ventilated 
baskets 44.7 F. The progress of cooling of the fruit during the 
48-hour period is graphically presented in Fig. 16. 

The difference in temperature between the two lots of fruit became 
less and less as time went on until the final reading at its destination, 
when the fruit in the standard baskets had attained a temperature 
lower than that in the ventilated baskets. This was 91 1/2 hours after 
the initial reading. 

Condition of Fruit at Destination. One hour after the last reading 
was made, the car was opened and the condition of the peaches noted. 
Fifty peaches were taken from each of four packages examined. 
Inspection of these samples resulted in the data given in Table 11. The 
amount of brown rot and number of soft peaches were too small in 
both types of packages to warrant any comparison. In one of the 



540 



BULLETIN No. 455 



[May, 



TABLE 11. DEFECTIVE PEACHES IN STANDARD AND IN VENTILATED CONTAINERS 
ON ARRIVAL IN MARKET AT BURLINGTON, VERMONT: CAR H 



Kind of package 


Brown rot 


Bruised peaches 


Soft peaches 


Standard basket 
Basket 1 


No. 
None 
None 
None 

None 
1 
1 


percl. 
None 

1.00 


No. 
2 
2 
4 

6 

1 
7 


perct. 
4.00 

7.00 


No. 
2 

2 
None 


percl. 
2.00 

None 


Basket 2 




Ventilated basket 
Basket 3 


Basket 4 







ventilated baskets there were more and in the other less bruised 
peaches than in either of the standard baskets. The peaches in general 
were firmer and greener in the ventilated packages than in the standard 
packages. 

GENERAL DISCUSSION OF RESULTS 

The outstanding feature in nearly all the tests just reported was 
the much more rapid reduction in the temperature of the fruit in the 
ventilated packages than in the standard packages. As was to be 
expected, the initial temperature of the fruit in the different cars and in 
different parts of the same car had a decided influence upon the rate of 
cooling, which varied considerably in the different tests and in differ- 
ent parts of a load. 

When the fan type of precooler was used, there was usually a 
greater drop in the temperature of the fruit in the top layer of packages 
than in that of the lower layer, during the time the precooler was in 
operation. This was due to the forcing of the cold air directly upon 
the top layer, where, under normal conditions in a refrigerator car 
temperatures are likely to be highest. When the portable precooling 
plant was used, there usually was not much difference in the average 
drop in the temperature of the fruit in the top and bottom layers, but 
there was a tendency toward a greater drop near the center of the car, 
especially in the top layer. 

Vagaries in rates of cooling in the same parts of different cars were 
doubtless due to differences in the adjustment of the precooling equip- 
ment and in details of operation. 1 * 

In general, more thoro precooling could have been attained if the 
equipment had been operated for a longer time on each car, and if a 
lower air temperature had been maintained during the cooling period 
than was maintained in most of the cars included in the tests. 



1939] PRECOOLING ILLINOIS PEACHES 541 

After the close of the precooling period the temperature of the 
fruit continued to decline, but the differences between the temperatures 
in the different types of packages tended to diminish. However, the 
favorable effect of the more rapid early cooling of the fruit in the 
ventilated packages was shown in the firmer condition of the fruit 
upon arrival in the terminal markets. 

COMMERCIAL PRACTICES IN 1938 

No test shipments in the precooling of peaches were made by the 
Illinois Experiment Station in 1938; but an effort was made to ascer- 
tain to what extent precooling of peaches was practiced by Illinois 
shippers that season, and also the extent to which ventilated packages 
were used in marketing the peach crop. 

Precooling. Personal contacts with peach growers during the 1938 
crop movement and consultation with operators of commercial pre- 
cooling equipment revealed that a number of Illinois growers handling 
large volumes of peaches had nearly all their rail shipments precooled. 
The charge for precooling was $12.50 to $25 a car. 

Equipment for precooling had been further improved for the 1938 
season ; and this, together with the experience of previous years, made 
more efficient precooling possible. Some operators of precooling equip- 
ment tried to get the temperature of the fruit down to 40 F., as 
recorded by a thermometer inserted into a fruit near the center of a 
basket in the top layer of baskets near the car door. To attain this 
temperature, precooling practices were varied to meet specific condi- 
tions. For example, the quantity of salt was varied from 200 to 400 
pounds to the car, the amount depending upon: (1) the initial tem- 
perature of the fruit, (2) the outside air temperature, (3) the amount 
of ice in the bunkers, and (4) the time available for precooling before 
the fruit train would arrive to pick up the car. 

One of the companies operating the fan type of precooler pre- 
ferred to have at least 8 hours in which to precool a car, but because 
of late loading of the car or early movement of the train on which 
shipment was desired, they were sometimes obliged to do the work in 
4 hours. When this occurred, more salt had to be used, and even then 
the desired temperature was not always attained. In fact, unless all 
conditions were favorable, the temperature of the fruit at the end of 
the precooling period was more likely to be in the neighborhood of 
50 F. than 40 F. In the report to the shipper the precooling com- 
pany recorded the initial and final temperature of the fruit, the amount 
of salt used, and the length of time the precooler was operated. 



542 BULLETIN No. 455 [May, 

Ventilated Baskets. The use of ventilated baskets for shipping 
peaches had become an even more common practice in Illinois in 1938 
than the precooling of rail shipments of this product. An incomplete 
survey made in southern Illinois during and shortly after the peach 
movement showed that 22 shippers used 128,201 ventilated bushel 
containers in the marketing of their peaches. The survey covered the 
operations of 126 growers, who marketed 460,002 bushels of peaches 
in 1938. Thus the ventilated packages used represented 28 percent of 
the total packages used by the growers included in the survey. Three 
years previous the only Illinois peaches shipped in ventilated packages 
were those included in the tests by the Experiment Station. The cost 
of ventilated packages and the new type of liners was practically the 
same as that of standard packages and the old type of liners. 

SUMMARY 

Refrigeration tests with eight carloads of Illinois peaches in 1935 
and 1937 are reported herein. The effects of two different types of 
packages ventilated and standard on the rapidity with which the 
fruit cooled were studied, half of each car being loaded with ventilated 
packages of fruit and half with standard containers. A special type of 
ventilated liner, not available in 1935, was used in the 1937 tests. 

Four of these cars were observed only during the precooling period, 
and four were followed thru to their destinations. In the latter tests 
the condition of the fruit was observed when the cars were unloaded. 

The precooling equipment was of two types. One consisted of 
electric fans (with accessories) which forced cold air from the ice 
bunkers thru the load of fruit. With this type of cooler, salt was added 
to the ice in the bunkers to reduce the air temperature. The other 
type of cooler consisted of a portable refrigeration plant mounted on an 
auto-truck chassis. 

The results of the 1935 tests, which covered only the precooling 
period, may be summarized as follows: 

1. The temperature of the fruit in the ventilated packages 
equipped with standard liners was reduced 25.8 degrees in 81/2 hours, 
while that of the fruit in the standard packages with standard liners 
was reduced only 18.4 degrees. (Car A) 

2. The temperature of the fruit in ventilated baskets without any 
liners was reduced approximately three times as much during a 6-hour 
precooling period as that of the fruit in the standard baskets equipped 
with standard liners. (Car B) 



1939] PRECOOLING ILLINOIS PEACHES 543 

3. In a car precooled with a portable refrigeration plant, the 
temperature of the fruit in the ventilated packages dropped 16.1 de- 
grees in 3f4 hours, while that in the standard packages dropped only 
11.9 degrees. The day was fairly cool and the temperature of the fruit 
not very high at the start. Standard liners were used in both types of 
package. (Car C) 

4. In a car loaded on a hot day, when the outside temperature 
was 94 F., the drop in the temperature of the fruit in the ventilated 
packages during a 4^-hour refrigeration period was 21.1 degrees, 
while in the standard containers it was only 12.7 degrees. The pre- 
cooling equipment was of the same type as that used for Car C just 
mentioned. ( Car D) 

The results of the 1937 tests, in which each car was followed thru 
to the terminal market and temperature readings were made enroute, 
were briefly as follows: 

1. In a car loaded with Red Bird peaches, and shipped under 
standard refrigeration without precooling, the temperature of the fruit 
in the ventilated packages was reduced 30.6 degrees in 22 hours ; while 
that of the fruit in the standard packages was reduced only 10.3 
degrees. The new type of 80-hole liner was used in both types of 
packages. (Car E) 

2. In a car precooled with the portable truck type of cooler, the 
average reduction in fruit temperatures in 3 hours was nearly the 
same in both the ventilated and the standard containers, both of which 
were equipped with the new type of ventilated liner. However, the 
amount of temperature drop in the fruit in the ventilated packages in 
different parts of the car was much less varied than it was in the 
standard packages. ( Car F) 

3. In a car precooled with the fan type of precooling equipment, 
the temperature of the fruit in ventilated tub bushels equipped with 
the new type of ventilated liner dropped 26.1 degrees in a 5-hour pre- 
cooling period, while in the standard tub bushels equipped with the 
standard type of liner the drop was only 10.5 degrees. (Car G) 

4. In a car in which precooling equipment was not installed until 
5 hours after loading was completed, the temperature of the fruit in 
ventilated baskets equipped with the new type of ventilated liner was 
reduced 9.3 degrees by the effect of the ice in the bunkers ; while in the 
standard baskets with the same type of liners the temperature dropped 
only 6.3 degrees. During the next 6 hours, while the precooler (fan 
type) was in operation, the fruit in the ventilated packages showed 



544 BULLETIN No. 455 

a further temperature drop of 16.1 degrees and the fruit in the 
standard packages a drop of 13.7 degrees. (Car H) 

5. Variations in the rate at which the peaches in the different 
tests cooled (both in 1935 and in 1937) were attributable partly to 
differences in the initial temperature of the fruit and partly to differ- 
ences in the operation of the precooling equipment. 

6. The peaches in both types of containers in the 1937 tests 
carried thru to their destinations in excellent market condition, tho the 
fruit in the ventilated packages was usually slightly firmer. The 
amount of brown rot and other decay was too small to warrant 
comparison. 

That precooling of rail shipments of peaches and the use of venti- 
lated containers are coming into favor among Illinois growers was 
indicated in contacts made with 126 growers in 1938. A number of 
those handling large volumes of peaches were precooling nearly all their 
rail shipments; and ventilated packages were used for marketing 
approximately 28 percent of the Illinois peach crop, according to an 
estimate based on interviews with these 126 growers, who marketed 
nearly half a million bushels of peaches in 1938. 

CONCLUSIONS 

1. Precooling is worthy of adoption as a general practice for rail 
shipments of Illinois peaches. 

2. For rapid precooling, the fruit should be packed in ventilated 
containers equipped with the new type of ventilated liners. 

3. Even for rail shipments of peaches that are not precooled, the 
use of ventilated packages is warranted because of the more rapid 
refrigeration which these packages permit. 

LITERATURE CITED 

1. ALLEN, F. W., and McKiNNON, L. R. Precooling investigations with deciduous 

fruits. Calif. Agr. Exp. Sta. Bui. 590. 1935. 

2. BROOKS, CHARLES, and COOLEY, J. S. Temperature relations of stone fruit 

fungi. Jour. Agr. Res. 22, 451-465. 1921. 

3. LLOYD, J. W. Precooling in relation to the marketing of Illinois fruits. Trans. 

111. State Hort. Soc. 69, 225-235. 1935. 

4. - and NEWELL, H. M. Observations on the refrigeration of some 

Illinois fruits in transit. 111. Agr. Exp. Sta. Bui. 334. 1929. 

5. and DECKER, S. W. Factors influencing the refrigeration of pack- 

ages of peaches. 111. Agr. Exp. Sta. Bui. 418. 1935. 

6. NEWELL, H. M., and LLOYD, J. W. Air circulation and temperature conditions 

in refrigerated carloads of fruit. 111. Agr. Exp. Sta. Bui. 381. 1932. 

6050 6M 16623 



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