HANDLING APPLES FROM TREE TO TABLE 



9 



age, cooling is accomplished by transferring heat from the fruit to the 

 outside air. A good ventilating system intelligently operated is neces- 

 sary to make this method efficient ; the vents should be opened when the 

 outside air temperature is lower than that of the fruit and closed when 

 conditions are reversed. In cold storage the heat is transferred from 

 the air surrounding the fruit to refrigerated pipes or other artificially 

 cooled surfaces and eventually is transferred to the outside air by the 

 refrigeration system. 



The cooling of the fruit ordinarily is not a rapid process, nor is its 

 ripening checked instantaneously when it is placed in cold storage. 

 Time is needed to remove the heat from the fruit because the rate of 

 cooling is affected not only by the temperature but also by the type 

 of package, the method of packing, the quantity of warm fruit placed 

 in the room, the manner in which the packages are stacked, and the 

 rate of air circulation around the fruit. Table 1 presents results of 

 tests conducted at the cold-storage laboratory, United States Horticul- 

 tural Station, Beltsville, Md., to determine the influence of the type 

 of package on the rate of cooling. In this series of tests the temperature 

 records were taken at the core of an apple at the center of each of the 

 various packages. The packages were not stacked and, being freely 

 exposed on all sides, cooled faster than they would under commercial 

 storage. 



Table 1.— Influence of method of packing and storing apples in unstacked 

 individual packages on their rate of cooling at 32° F. in still air 



Package 



Packing material 



Temperature at core of apple in center of 

 package — 



When 

 stored 



After 

 12 hours 



After 



18 hours 



After 

 72 hours 



After 

 7 days 



After 

 10 days 



Bushel basket __ 



None . - _ _. __ 



°F. 

 63 

 70 



66 

 71 

 66 



°F. 

 42 

 59 



64 

 67 

 63 



°F. 

 32 

 44.5 



59 

 60 



61 



°F. 



°F. 



°F. 



Do 



Liner, cushion, shredded oiled 



paper. 

 None 



Liner, cushion, oiled wraps 



Liner, cushion, shredded oiled 

 paper. 



41 



55 

 54 

 59 



33.5 



41 



41.5 



54 



32.5 

 36 



Standard box 



Hi-bushel eastern 

 crate. 



37 

 44 



The results show that the use of liners, cushions, and paper for 

 packing slows up the rate of cooling. Apples in an open bushel basket 

 just as they came from the orchard, without liners, wraps, or shredded 

 oiled paper, cooled from 63° F. to 32° in 18 hours, whereas fruit- 

 packed in lined baskets with a pad under the lid and shredded oiled 

 paper well distributed throughout required about 10 days to cool from 

 70° to 32.5°. The relative thickness of the containers doubtless had 

 an effect on the rate of cooling, but the size of the package or the 

 mass of fruit enclosed and the tightness of closure apparently were 

 important factors also as can be noted by comparing the results for 

 apples packed in the barrel with those in the open bushel basket; it 

 took only 18 hours to cool the fruit in the middle of the bushel basket 

 from 63° to 32°, but it required 10 days to cool that in the middle 

 of the 3-bushel barrel from 66° to 36°. Similar results can also be 



467795°- 



