Gamma Radiation of Fruits to Extend Market Life

Report Summary: Eleven kinds of fresh fruits were irradiated to determine possible extension of the market life. Irradiation of strawberries and two varieties of fig extended the market life by several days through reduction of decay, without apparent impairment of fruit quality. Brown rot, but not Rhizopus rot, of peaches and nectarines was controlled; the peaches softened during irradiation and subsequently developed more red color but less flavor than the controls. Radiation inhibited blue coloring of plums and increased softening of the fruits. Low doses inhibited ripening of pears by several days, but the resultant ripening was abnormal. Decay of grapes was controlled less effectively by radiation than by the customary sulfur dioxide fumigation. Radiation increased rind pitting of oranges without reducing decay during semicommercial tests. Irradiated apples were softer, more shriveled, and had less flavor than the controls following storage for 3 to 6 months. Avocados and olives were severely discolored both internally and externally by radiation. Individual varieties of peaches and figs responded quite differently to radiation. Water on the surface of peaches during irradiation caused spotting of the skin. The stage of development of fungal infections determined the effectiveness of radiation as a decay-control agent for oranges. Fruit maturity within the limits of these experiments did not affect the responses to radiation