Chilling Injury of Tropical Horticultural Commodities

Most tropical horticultural commodities are sensitive to chilling temperatures. Therefore, chilling injury (CI) is a serious problem in the postharvest handling of tropical horticultural commodities. From the standpoint of CI, we can classify all horticultural crops into three categories: A) chilling resistant; B) chilling sensitive; and C) slightly chilling sensitive. The storage life of commodities in group A is inversely related to storage temperature. The lower the storage temperature, the longer the storage life, as long as the temperature is not below the freezing point. The storage life of commodities in group B increases with decreasing storage temperature down to a certain point; then, storage life decreases with any further temperature decrease. This point is called the critical chilling temperature. It usually occurs at ≈10 to 13C. Most crops of tropical or subtropical origin are chilling sensitive and belong to group B. The critical chilling temperature in group C plants is lower than that in group B plants. It usually occurs at ≈3 or 4C. Some temperate crops are in this group, such as ‘McIntosh’ apples (Malus domestica Borkh.). About one-third of all fruits and vegetables in U.S. markets are susceptible to CI. Most of the susceptible crops are of tropical or subtropical origin.