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CIRCULAR NO. 447 e;flr[ of file* OCTOBER 1937 



UNITED STATES DEPARTMENT OF AGRICULTURE 

 WASHINGTON D. C 



THE FREEZING TEMPERATURES OF SOME FRUITS, 

 VEGETABLES, AND FLORISTS' STOCKS' 



B}- R. C. Wright, physiologist, Division of Fruit and Vegetable Crops and Diseases, 

 Bureau of Plant Industry . ~ q i 



Page 



Introduction 1 



Freezing points of fruits 3 



Apples 3 



Cherries 5 



Grapes 6 



Oranges 6 



Peaches 6 



Pears 6 



Plums 6 



Strawberries 6 



Blackberries, raspberries, and cranberries 6 



Page 



Freezing points of fruits— Continued. 



Miscellaneous fruits.- 7 



Freezing points of vegetables 7 



Potatoes 8 



Sweetpotatoes 8 



Tomatoes 8 



Sweet corn 8 



Miscellaneous vegetables 8 



Freezing points of florists' stocks 8 



Summary 10 



INTRODUCTION 



There is an ever-increasing demand from persons interested in the 

 growing, shipping, and handling of produce for exact data on the 

 freezing points, or the temperatures at which actual ice formation 

 takes place in various products. 



The extent of damage due to the freezing of produce in transit 

 naturally varies from year to year, but it is usually very heavy, 

 aggregating frequently several hundred thousand dollars during a year. 

 This in general applies not only to such products as apples and pota- 

 toes, most of which are grown in the North and harvested and shipped 

 in the late fall and winter, but to products that are grown in the South 

 and Southwest during the winter and shipped to northern markets. 

 This latter group includes citrus fruits, strawberries, tomatoes, lettuce, 

 string beans, cabbage, cauliflower, eggplant, etc. Cars of these food 

 products often leave the shipping point under refrigeration and in 24 

 to 36 hours may pass into a zone of freezing temperatures. As they 

 approach the more northern markets they may be exposed to tempera- 

 tures ranging several degrees below their freezing point. Under 

 certain conditions when harvested in warm weather some of these 

 products are precooled — that is, rapidly cooled to a refrigerating 

 temperature, either immediately before or directly after they are 

 placed in the car for shipment, in order to delay maturity and conse- 

 quent deterioration. Where precooling is practiced, it is, of course, 

 essential to know the temperatures to which the product can be 

 lowered with absolute safety. 



1 This circular is a revision of and supersedes Department Bulletin 1133, The Freezing Temperatures of 

 Some Fruits, Vegetables, and Cut Flowers. 



1221° — 37 1 



