Abstract
Various practices of cooling citrus to mitigate disorders such as peel pitting and to extend the fruit storage life are now being adopted in Florida's fresh citrus industry. However, refrigeration systems, temperature recommendations, and post-packing handling logistics vary widely and the corresponding engineering economics have not been established. Facilities range from elaborate forced-air pre-cooling units to minimal natural convection air-conditioned room cooling. In this study, the range of temperature and relative humidity conditions found in commercial citrus storage facilities was established. Average temperature and relative humidity varied from 6.1 to 12.5°C and 80.0 to 91.7%, respectively. A small forced-air cooler was evaluated by which cooling time, represented by 50% mass average position temperature reduction, was reduced by a factor of 3 or greater dependent upon depth of cartons and venting patterns. Weight loss and peel injury were assessed for Fallglo' tangerine, 'Marsh' grapefruit, and 'Valencia' orange as a function of cooling and wax treatments. Pitting and weight loss were highest for unwaxed fruit or fruit treated with shellac wax and subsequently stored at 20°C, as compared to carnauba or polyethlene waxed fruit held at 5°C.
