HANDLING APPLES FROM TREE TO TABLE 15 



flavors, sometimes in tissue breakdown. In apple waxing care must be 

 taken to see that the wax used, or the thickness of its application, will 

 not greatly interfere with normal respiration. If the apples are packed 

 in consumer units of Pliofilm or similar transparent film, provision for 

 gas exchange is necessary. If the package is sealed by heat or stapling, 

 perforation of the film is essential to allow sufficient oxygen to reach the 

 fruit. Such perforations are not necessary if incomplete closures, such 

 as the "snap sack," are used. Such openings do not seriously reduce the 

 effectiveness of the film in protecting the fruit against moisture loss. 



Storage With Other Products 



Apples absorb odors very readily; it is therefore undesirable to store 

 them with other products that have pronounced odors. This is particu- 

 larly true of potatoes and other root crops, which often give apples an 

 earthy flavor. As apples give off ethylene, a gas that stimulates respira- 

 tion and ripening, the potential keeping quality of other products stored 

 with apples may be adversely affected. This is particularly true of cut 

 flowers, which may be made to shed their petals or are otherwise injured 

 by ethylene {28). 



Air Purification 



Recirculation of storage air through activated coconut shell charcoal 

 has been suggested as a means of removing odors and the products of 

 fruit respiration from the atmosphere in apple storages {25). This is an 

 effective means of adsorbing odors until the adsorptive capacity of the 

 charcoal filters is reached, whereupon it is necessary to replace the char- 

 coal with a fresh charge. It has been found (6) that, although this ma- 

 terial removes odors, it is relatively ineffective in removing ethylene, a 

 product given off by ripening apples that stimulates the ripening proc- 

 esses in fruits. Air purification with activated charcoal removes volatile 

 products other than ethylene sufficiently to reduce the intensity of apple 

 scald, but it does not prevent scald as effectively as oiled paper. Ozone 

 in apple storage removes odors and controls surface molds on packages 

 and walls, but does not reduce decay or control scald (22a). 



Fungus Diseases 



Many fungus diseases of apples can cause serious losses under certain 

 conditions. Fortunately, however, most of them are primarily orchard 

 diseases and are controlled on the harvested fruit by the sprays that 

 growers apply to control them in the orchard. However, if they are 

 present on the stored fruit, they respond to storage temperatures about 

 the same as do the physiological processes of the fruit (p. 9). All 

 develop rapidly and are most destructive at higher temperatures; at 30° 

 to 32° F. many will not develop at all, or at the most very slowly, particu- 

 larly if the apples are not ripe. The spores of most rot organisms will 

 not germinate at 30° to 32°, but if infection is already present when 

 apples reach this temperature, most of the rots will persist during stor- 

 age and the causal organism will resume growth after the fruit is re- 

 moved to a warm place. Detailed information on the diseases of apples 

 in storage is given in other publications of the United States Department 



947960—51—3 



