HEAT STERILIZATION OF MANGOES AND GUAVAS FOR FRUIT FLIES

Abstract

1. Mango fruits infested with fruit fly maggots have no commercial value and could not profitably be shipped to the United States. 2. Sterilization at a temperature of 43°C for eight hours in a circulating atmosphere saturated with moisture kills the eggs, maggots and pupae of the fruit flies that infest mangoes and guavas in Puerto Rico without unfavorably affecting the flavor, appearance or keeping qualities of the fruit if it is afterwards placed in refrigeration. 3. Sterilization does not render marketable mangoes which have already been injured by fruit fly maggots. Such fruit shows the injury and the dead maggots on being cut open, and decays rapidly. 4. Sterilized mangoes from Puerto Rico could safely be allowed into the United States under permit because (1st) only varieties that are not infested would be shipped and (2nd) the fruits would in addition have been submitted to a treatment which renders them free from the pest if they contained it. 5. The varieties that could be sterilized are the Mayagüez mango, the Girón, the Colombo kidney and some of the better ones from Vieques. 6. Since the period of sterilization of eight hours can be reduced to four hours without rendering the treatment less effective in destroying the insect, the margin of safety is very large. 7. Mangoes can be rendered free from fruit fly infestation by sterilization for 8 hours at 43°C piled on trays, crated or wrapped in paper and crated.