18 



CIRCULAR 2 7 8, U. S. DEPARTMENT OF AGRICULTURE 



Table 5. — Effect of storage of various avocado varieties at different 

 temperatures on their marketable life x 









Period 



• 







Opti- 



Period 



there- 



Period 



market- 

 able after 

 softening 



Gain in 





mum 



held at 



after at 



market- 



Variety 2 



tempera- 



optimum 



room 



able life 





ture for 



tempera- 



tempera- 



due to 





storage 



ture 



ture for 



storage 









softening 









o p 



Days 



Days 



Days 



Days 



Pollock (WI) 



42 



21 



3 



3 



17-19 



Trapp (WI) 



42 



21 



4-6 



2-5 



18-20 



Waldin (WI) 



( 3 ) 











Collinson (G X WI) 



42-48 



14 



4-6 



3-4 



7-8 



Booth 8 (G X WI) 



42 



14 



4-6 



1-4 



7-9 



Lula (G X M) 



37 



28 



3-6 



2-3 



20-24 



Tavlor (G) . . 



37 



28 



4-6 



2-3 



23-26 







1 Adapted from Wolfe, Toy, and Stahl {115). 



2 WI, West Indian; G, Guatemalan; M, Mexican; 



Mexican; G X WI, Guatemalan X 

 3 Cold injury noted even at 48 c 



West Indian, 

 storage. 



G X M, Guatemalan X 



At the higher temperatures mentioned, in the text, anthracnose, a 

 fungus disease of avocados, will probably be an important factor in the 

 storage of this fruit. At the lower temperatures decay is not likely to 

 be troublesome after long storage. 



Bananas 



(Temperature: ripening, 62° to 70° F. ; holding ripe fruit, 56° to 60°. Relative 

 humidity: green fruit, 90 to 95 percent; ripe fruit, somewhat reduced but 

 not below about 85 percent) 



The banana is one of the fruits that must be shipped to market 

 green, because in this condition it can be handled for a longer time 

 without becoming overripe and without serious injury from bruising 

 during the marketing process. Furthermore, bananas of the Gros 

 Michel variety, which make up the great bulk of banana shipments 

 into this country, if allowed to ripen on the plant become mealy, lack 

 flavor, and are subject to splitting, with subsequent decay. 



The bunches of green bananas as they are received from the Tropics 

 are usually ripened at a temperature of about 64° F., with a relative 

 humidity of 90 to 95 percent or higher. If it is desired to hasten the 

 ripening process, a higher temperature can be used (up to 70°) for the 

 first 18 to 24 hours, but temperatures should then be reduced to about 

 66°. In any case the relative humidity should be kept at 90 to 95 

 percent or higher until the fruit becomes thoroughly colored. After 

 this it should be reduced slightly, but not below about 85 percent. 

 Prolonged exposure to high temperatures will cause poor color and 

 flavor and weak necks and will hasten decay. 



The lowest temperature at which green bananas can safely be held 

 in order to delay ripening is about 56° F. ; below this they suffer an 

 injury known as chilling — a form of peel injury to which both green 

 and ripe bananas are susceptible, caused by low but not freezing tem- 

 peratures. Ripe fruit is slightly more susceptible to chilling injury 



