Cold storage effects on fresh market peaches, nectarines & plums estimating freezing points using low temperatures to delay internal breakdown

Fruits for fresh market distribution commonly are stored under refrigeration in or near areas where they are grown. Cold storage delays ripening. The effective marketing season is expanded, and the advantages of greater shelf life potential for the product can be passed on to the consumer. However, many varieties of California peaches, nectarines, and plums are subject to a low-temperature internal breakdown that may (1) limit the time fruit can be held and still ripened normally; or may (2) produce internal browning, (3) mealiness, or (4) combinations of the above.

The two articles presented here report research to determine the critical temperature levels at which fruit can be held with least danger of either freezing or internal breakdown. These levels are correlated with soluble solids, or fruit sugar levels. Generally, breakdown is most severe under storage between 2.2 to 5° C (36 to 41° F), and least severe at or near 0° C (32° F). Temperatures above 5° C (41° F) result in rapid tissue softening and quicker ripening. There are indications, however, that periodic exposure of low temperature fruit to temperatures in the 20 to 40° C range (68 to 104° F) delays onset of breakdown, but this requires further study.