COLD STORAGE FOR APPLES AND PEARS 5 



tures of some fruits are given in table 1 ; for more detailed informa- 

 tion on this subject see Circular 447 {26). 



Table 1. — Average freezing temperature of various fruits 





Fruit and variety 



Freezing 

 tempera- 

 ture 



° F. 

 29.0 

 28.4 

 28.3 

 28.2 

 28.0 



28.5 

 27.8 



26.9 

 27.2 



24.1 

 25.3 

 28.0 



Fruit and variety- 



Freezing 

 tempera- 

 ture 



Apples: 



Peaches: 



Elberta 



° F. 

 29.7 





J. H. Hale 



29.6 





Grapes: 



American, or labrusca, type: 

 Moore Early - ._ ._._. 











28.3 







26.7 





Concord . 



27.2 





Delaware . . . . _. 



24.6 



Soft ripe . ._. .-- 



European, or vinifera, type: 



Ohanez (Almeria)__ - 





Anjou: 



Hard ripe 



25.6 



Alphonse Lavallee (Ribier) 



24.8 

 24.6 



Cherries: 

 Bing: 



Sultanina (Thompson Seedless) . 



23.6 







Sour .- -. - - 









Humidity 



The loss of moisture from apples and pears in storage, resulting in 

 shriveling or wilting, is directly related to moisture in the form of 

 water vapor in the storage atmosphere. When the humidity is main- 

 tained at above 90 percent, the development of fruit rots is encour- 

 aged as well as surface-mold growth on the fruit, on the walls, ceil- 

 ings, and floors of the storage room, and on the packages. Under 

 ideal conditions of humidity, with active air movement, apples and 

 pears may be kept in cold-storage rooms without risk of excessive mois- 

 ture loss, but when the relative humidity is low, shriveling is aggra- 

 vated by moving air, particularly when the fruit is stored without 

 wraps. A relative humidity of 85 percent is considered ideal for 

 most fruits. 



Air Circulation and Ventilation 



Apples and pears should be stored in an atmosphere free from 

 pronounced odors. They acquire off-flavors when stored with pota- 

 toes, onions, cabbage, and certain other products. If stored by them- 

 selves, most fruits do not require a change of the air other than that 

 occasioned by the opening of doors or ports under normal operation, 

 provided the fruit is not overripe when received and is quickly cooled 

 to an optimum storage temperature. 



In most parts of the United States it has not proved practical to 

 substitute natural cold air for mechanical refrigeration during winter 

 months, so that it is seldom advisable to make any special provisions 

 in the storage designs for bringing in outside air. 



In the storage of apples there is an advantage in having active 

 air movement about the packages, particularly with varieties sus- 

 ceptible to apple scald. Less scald develops when they are stored in 

 moving air. A heavy odor in an apple storage means that some of 



