Jonizing radiation can be effectively applied to fruits and vegetables for several purposes. The most feasible and potentially useful application is probably for d&infestation as a quarantine treatment. All stages of a fruit fly will become sterile upon being irradiated at a minimum dose of 0.15 kGy, the dose level approved by the USDA in January 1989 for treating Hawaiian papa i as as a quarantine procedure. Thts is also well below the dose level approved in April, 19 6 by the U.S. Food and Drug Administration for irradiating fresh foods for disinfestation and delaying maturation. Research on irradiation of several tropical fruits such as papayas, mangoes, lychees showed that the chemical, sensory and nutrient qualities of these fruits were well retained at 1 .O kGy, and the fruits would ripen normally or slightly delayed.
Since September, 1984, thermal methods used by the papaya industry after ethylene dibromide was banned require treatment time of up to 7 hrs and have caused quali problems.
1 Some of the fruits treated by the hot air or the double-dip hot water method lac flavor and had lumpy texture. The vapor heat method as now used is quite expensive. Irradiation studies have proved the efficacy of the process to disinfest tropical fruits of fruit flies. Market test of irradiated Hawaiian papayas in 1987 showed that consumers preferred irradiated papayas over hot water treated papayas by 11 to 1. Thus the only hurdle to overcome in using irradiation for tropical fruits is to convince the consumers that irradiated fruits are wholesome and safe for human consumption, which has been amply proven with scientific data obtained during the past three decades, and further proven with the marketing of irradiated fruits in the U.S.A. since early 1992.