Effects of60Co Gamma Irradiation on Aflatoxin B1and B2Production byAspergillus Flavus

SUMMARYGermination of spores of the toxinogenic organism Aspergillus flavus NRRL-3145, previously exposed to specific gamma radiation levels, resulted in a greater production of aflatoxins B1 and B2 following inoculation onto a cracked wheat medium or into a synthetic liquid medium than did similarly treated nonirradiated controls. The most notable increases in aflatoxin production occurred from cultures developing from spores having been irradiated with 50, 100, 150, or 200 krad of gamma radiation. Exposure to 400 krad resulted in complete inhibition of spore germination and consequently negative toxin production. Of the two aflatoxins studied (B1 and B2), the quantities of B2 toxin produced were significantly lower than that of B1 toxin except in synthetic medium where B2 production was comparable to that of B1.Analysis of variance revealed that substrate, time of incubation following the respective irradiation doses, as well as radiation levels, all affected the quantities of aflatoxin produced by this organism.