FREEZING INJURY OF FRUITS AND VEGETABLES 



29 



maintained for several days. Under such extreme treatment, 

 fruits and vegetables may become frozen to death and do not re- 

 turn to normal appearance or condition when they thaw. Repeated 

 freezing and thawing are injurious to products, such as apples, 

 sprouting broccoli, brussels sprouts, cabbage, cauliflower, and 

 onions, that are injured very little if at all by only one light freez-. 

 ing unless they are handled while frozen. 



Certain fruits and vegetables are susceptible to chilling injury 

 by temperatures that are not low enough to cause them to freeze. 

 The relative susceptibility of these products to such injury is 

 shown in tables 2 and 3. 



Table 2. — Commodities susceptible to chilling injury at only moderately low 

 temperatures (45° to 55° F.) 1 



Commodity 



Freezing 

 point 



Dangerous 

 temperature 



Limit of safe 

 exposure 



Character of injury 



Avocados 



0^ 



27 

 30 

 28 

 29 



(3) 



F. 

 Below 42 X. 



Below 55 

 or 56 



4 weeks to 2 months, 

 depending on variety... 



Internal browning. 

 Dull color when rip- 









Below 50 



Below 45 



do 



Pitting, membranous 

 stain, and red blotch. 



Rind spotting. 



Dull green color when 

 ripened. 

















i Temperatures lower than these cause more serious injury. 



2 For commercially important varieties. 



3 Mature green, 29.1° ; ripe, 29.9°. 



Table 3. — i 



Commodities susceptible to chilling 

 close to 32° F. 



injury at temperatures 



Commodity 



Freezing 

 point 



Dangerous 

 temperature 



Limit of safe 

 exposure 



Character of injury 



Cranberries 



°F. 



27 



30 

 30 

 29 

 29 



30 



°F. 

 Below 34.... 



Below 40 



do 



About a month.. 



About 2 weeks.. 

 About 10 days.. 



About 1 week.. 



About 2 to 3 1 

 weeks. [ 



6 weeks to 2 | 

 months. J 



About 8 days ] 



2' to '8 weeks J 



Rubbery consistency and 

 diffusion of red color 

 through the flesh. 1' 



Water-soaked spots on sur- 

 face. 



Internal browning and 

 dried-out surface spots. 



Eggplant 



Potatoes, white.. 



do 





f 40 





Sweetpotatoes.... 



] 50 to 55... 

 f 32 



Decay. 



Susceptibility to decay ; fruit 

 of poor quality and color 



Tomatoes 



\ 40 









From the results of experiments, the observation of produce 

 under commercial conditions, and the experience of commercial 

 operators various fruits and vegetables can be grouped as follows 

 on the basis of their susceptibility to freezing injury. 



