(195) Optimizing Storage Conditions for Fresh Cranberries
Extending the storage life of fresh cranberries (Vaccinium macrocarpon Ait.) requires an optimum storage environment to minimize decay and physiological breakdown (PB). To assess the effects of relative humidity (RH) and temperature on storage life, cranberry fruit from four bogs were stored over calcium nitrate, sodium chloride, or potassium nitrate salts, which maintained RH at 75%, 88%, and 98%, respectively. Containers at each RH were held at 0, 3, 5, 7, or 10 °C and fruit quality was evaluated monthly for 6 months. Both decay and PB increased with increasing RH in storage. After 6 months, 32%, 38%, and 54% of fruit were decayed and 28%, 31%, and 36% developed PB when stored in 75%, 88%, and 98% RH, respectively. The effects of RH continued to be apparent after fruit were removed from storage, graded, and held for 7 days at 20 °C. The decay of graded fruit after 4 months of storage in 75%, 88%, or 98% RH was 10%, 13%, and 31%, respectively, while PB was 12%, 12%, and 17%, respectively. Fresh weight loss decreased as RH increased averaging 1.9%, 1.4%, and 0.7% per month for storage in 75%, 88%, and 98% RH, respectively. Fruit firmness was not affected by RH. Storage temperature had little effect on decay. However, PB was greatest in fruit stored at 10 °C, encompassing 55% of fruit after 5 months of storage. When graded fruit were held an additional 7 days at 20 °C, decay and PB were greater in fruit previously stored at 0 or 3 °C than at 5, 7, or 10 °C. Fresh weight loss increased as storage temperature increased, averaging 0.8%, 1.0%, 1.3%, 1.7%, and 1.9% per month at 0, 3, 5, 7, and 10 °C, respectively. Fruit firmness decreased during storage, but was not affected by storage temperature. To maximize storage and shelf life, cranberry fruit should be stored in a RH of about 75% at 5 °C.