COMMERCIAL STORAGE OF FRUITS AND VEGETABLES 31 



SPINACH 

 (Temperature, 32° F. ; relative humidity, 90 to 95 percent) 



Spinach is usually stored only for short periods. It should keep 

 fairly well for a week or two after cutting. If crushed ice is used 

 in the packages, this period can be extended somewhat. 



SQUASHES 



See pumpkins. 



SWEETPOTATOES 

 (Temperature, 50° to 55° F. ; relative humidity, 80 to 85 percent) 



The requirements for the successful storage of sweetpotatoes differ 

 from those recommended for most other vegetable crops. When 

 freshly dug sweetpotatoes are to be stored for any length of time 

 they should be given a preliminary curing treatment to permit 

 the healing of all wounds or abrasions incident to harvesting and 

 handling, in order to prevent the entrance of decay organisms. 



The curing and storing are done in the same house so that the 

 potatoes do not have to be moved after the curing treatment. When 

 commercial lots are handled the storage house is generally of 

 special construction with sufficient insulation to maintain a uniform 

 temperature, and some means of ventilation that will insure the 

 desired humidity. Provision should be made for heating the build- 

 ing during the curing process and for holding the proper storage 

 temperature afterward. The curing process ordinarily takes from 

 10 to 14 days, during which the house is kept at a temperature of 

 80° to 85° F., with a relative humidity of 80 to 90 percent. After 

 the curing period the storage temperature is allowed to drop to a 

 range of 50° to 55° with a humidity of 80 to 85 percent. Short 

 periods of a few hours at temperatures somewhat lower than 50° need 

 not cause alarm, but prolonged periods should be avoided because of 

 the danger from certain types of decay which are more likely to 

 develop at temperatures below the range given (10, 28). 



Only well-matured stock that is practically free from mechanical 

 injury or decay should be used for storage. Sweetpotatoes are 

 usually stored in slat crates of about a bushel capacity or in bushel 

 baskets. Shallow bins are sometimes used. 



TOMATOES 



(Temperature, ripe, 50° to 55° F. ; mature green, 55° to 70° F. ; relative humidity, 80 to 



85 percent) 



Ripe tomatoes are held in storage only temporarily and should 

 not be stored at temperatures lower than 50° F. At 50° to 55°, if 

 not already soft ripe, they will keep in good condition for a week 

 to 10 days ; at temperatures lower than this they sometimes show a 

 tendency to break down. 



Green tomatoes are best kept at a temperature not lower than 55°. 

 At this temperature, ripening progresses slowly but satisfactorily 

 and mature green tomatoes can be kept for 1 to 6 weeks before be- 

 coming overripe. At temperatures below 55° green tomatoes do 

 not ripen well, and if kept there more than 5 to 8 days and then 



