24- 



to 35°F had 7 to 9% rot. After a second day without refrigeration 

 the rapidly cooled berries now had about 151 rot and those not 

 cooled to 35°F before marketing had 301 rot. 



In a second test some of these berries were cooled to 35°F 

 in 2 hours, and others were cooled to 35°F over the course of 

 either 24 or 48 hours. They were all kept at 350F for 10 days 

 and then placed at 70OF for 1 or 2 more days. This test there- 

 fore examined the importance of the speed of cooling. 



Right out of storage, the berries cooled over the course of 

 1 or 2 days had about 4% rot while those cooled quickly had about 

 21 rot. After 1 day without refrigeration the amount of rot had 

 doubled, and after an additional day without refrigeration the 

 amount of decay tripled again, so that 2 days after removal from 

 storage over 201 of the slowly cooled berries were rotting while 

 about 10% of the quickly cooled berries were rotting. 



These tests showed that rapid and continual refrigeration can 

 control rotting of blueberries during the normal transit and 

 marketing periods. The best temperature for blueberries is about 

 320F. 



One cause for concern about refrigerating berries is the 

 moisture that condenses on their surface when they are removed 

 from the cold. Condensation might cause loss of bloom, and many 

 shippers and receivers believe that condensed moisture will 

 increase the amount of rotting. While it is true that moisture 

 on berries can help mold spores germinate and grow, there is no 

 clear evidence that it actually increases rot because the cooled 

 berries are in better condition and can resist infection better 

 than berries of the same age that were not properly cooled. 



Hudson and Tietjen concluded that by rapidly cooling blue- 

 berries to near 320F and keeping them at this temperature, they 

 should be suitable for shipment by boat to Europe. If they can 

 withstand this kind of transport, it should certainly be worth- 

 while to refrigerate blueberries thoroughly before they enter 

 the normal marketing channels. 



