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IS IT WORTHWIILE TO REFRIGERATE BLUEBERRIES? 



William J. Bramlage 

 Department o£ Plant and Soil Sciences 



Blueberries are not stored for prolonged periods of time 

 because their relatively short postharvest life, even at low 

 temperatures, does not make this practical. In fact, many are 

 not stored at all, being sold directly to the consumer at 

 harvest. Yet, some do pass through marketing channels and 

 their short postharvest life can lead to substantial losses, 

 usually due to berry rotting. 



As with all plant materials, blueberry postharvest life 

 can be extended considerably by refrigeration. Most plant 

 materials change as much in 1 day at 85°F as they do in about 

 2 weeks at 32of. Still, many blueberries are sent to the mar- 

 ket without refrigeration, and it is reasonable to ask whether 

 or not it would be worthwhile to refrigerate them first. 



Two recent reports from New Jersey are enlightening. One 

 by Cappellini, Ceponis , and Koslow (HortScience 17: In press) 

 of Rutgers University assessed the extent of defects in blue- 

 berries on the counter in New York City supermarkets. They found 

 that an average of IS-o of the berries were defective, with rots 

 accounting for two-thirds of these defects. Shriveling, 

 mechanical damage, and overrjpeness accounted for the other 

 one- third of the defects. As would be expected, the percent 

 of fruit that were defective was higher for late harvests than 

 for early harvests (about 20% vs. 10^). These results show 

 clearly that thereis a problem with quality of blueberries in 

 the supermarkets. 



The second report, by Hudson and Tietjen (HortScience 16: 

 656-7) of the USDA Lab in New Brunswick, N J , shows the impact 

 that refrigeration can have on blueberry losses. They obtained 

 commercial Bluetta and Bluecrop berries, which at the packing- 

 house had temperatures ranging from 72 to 850F. 



In 1 test, some of these berries were cooled to 35^F in 2 

 hours while others were cooled to only 50°F over the course of 

 24 hours . Both batches of berries were then put in a 50 F room 

 for 3 days, after which they were put at 70°F for 1 or 2 days. 

 This test examined the value of rapid cooling to a low temperature 

 before marketing with limited refrigeration. 



After the 3 days at 50°F, all of the samples had 2-3% rotted 

 berries. However, after an additional day without refrigeration 

 (as is often the case in the market) the berries that were rap- 

 idly cooled to 350F still had about 3% rot while those not cooled 



