Optimizing the Storage Temperature and Humidity for Fresh Cranberries: A Reassessment of Chilling Sensitivity

Abstract

Studies were conducted over three seasons to determine the relationship of temperature and humidity on the storage life of fresh cranberry (Vaccinium macrocarpon Aiton) fruit. Each year, cranberries harvested from four commercial bogs were stored at temperatures ranging from 0 to 10 °C in combination with relative humidities (RH) ranging from 75% to 98%. Fruit were stored under these conditions for up to 6 months and were evaluated monthly for marketability, decay, physiological breakdown, weight loss, and firmness immediately after removal and after an additional week at 20 °C. The percentage of marketable fruit declined substantially over time in all storage conditions with 41% to 57% becoming unmarketable after 2 months as a result of both decay and physiological breakdown. Relative humidity had a greater effect on fruit storage life than temperature and after 5 months, the amount of marketable fruit stored in high (98%) and medium (88%) RH was 71% and 31% less than that stored in low (75% to 82%) RH. Rates of fresh weight loss increased as RH in storage decreased and was 0.41%, 0.81%, and 0.86% per month in fruit stored in high, medium, and low RH, respectively. Fruit firmness was not significantly affected by RH. The effects of storage temperatures ranging from 0 to 7 °C on marketable fruit after 2 to 5 months of storage were not significant. Only fruit stored at 10 °C consistently had fewer marketable fruit when compared with fruit stored at lower temperatures. Storage temperature had no significant effect on decay incidence. However, physiological breakdown was greatest in fruit stored at 10 °C. Rates of fresh weight loss increased with storage temperature, ranging from 0.35% to 1.17% per month for fruit stored at 0 to 10 °C, respectively. Contrary to previous reports, no evidence of chilling injury was found in cranberry fruit stored at 0 °C. Results suggest that cranberry fruit should be stored at 0 to 7 °C and 75% to 82% RH to retain marketable fruit.