Influence of gamma irradiation of aflatoxin B1 production by Aspergillus flavus growing on some Nigerian foodstuffs.

Spores of Aspergillus flavus (UI, 81) inoculated into some local food materials were irradiated at 62.5, 125.0, 250.0 and 500.0 krad, and the effect on aflatoxin B1 production on subsequent incubation was measured. The results show that aflatoxin B1 production decreased with increasing gamma irradiation dose in soya bean, groundnut, palm juice, while paw paw mash showed a relatively high yield of aflatoxin at 125.0 krad as compared to other irradiation levels tested except for the control. Irradiation of soya bean and groundnut inoculated with spores of Aspergillus flavus at 500.0 krad (pre-irradiation incubation period of 2 h) inhibited aflatoxin B1 production. Analysis of variance showed that media, pre-irradiation incubation periods and irradiation levels affected the total amounts of aflatoxin produced.