Chilling Injury of Grapefruit and its Control

Chilling injury (CI) is a physiological disorder that is occasionally reported on fresh citrus shipments from Florida. It is most often characterized by areas of the peel that collapse and darken to form pits (Figure 1). Pitting is not targeted to the oil glands. Less severe symptoms may show up as circular or arched areas of discoloration or scalding. Symptoms of CI are typically more pronounced after fruit are warmed to room temperature following exposure to the chilling temperature. CI symptoms generally require at least 3 to 6 weeks to develop at low (e.g. 40°F) shipping and storage temperatures. Chilled fruit are also more susceptible to decay than are non-chilled fruit. CI is often confused with another physiological disorder called postharvest pitting (PP) that is caused by low-oxygen concentrations (< 9%) within waxed fruit and is visible as collapsed oil glands. PP requires only 2 to 4 days for symptom development after waxing and appears in fruit held at warm (> 50°F) tempera