INFLUENCE OF GAMMA-RAYS AND SODIUM-CHLORIDE ON AFLATOXIN PRODUCTION BY ASPERGILLUS-FLAVUS

The rate of Aspergillus flavus growth and production of aflatoxin in y east extract sucrose medium generally decreased as the concentrations of NaCl increased from 2 to 12%. Maximum production and accumulation o f aflatoxin at 28 degrees C occurred after 7 days in the presence of N aCl concentrations;. The number of colony forming units of A. flavus a fter 1.0 or 2.0 kGy irradiation was lower than in the unirradiated con trols and the mould was eliminated at 3.0 kGy. Aflatoxin B-1 decreased from the control level of 46 mu g kg(-1) to 10 mu g kg(-1) at an irra diation dose level of 2.0 kGy. Viable gamma irradiated conidia (2.0 kG y) of A. flavus showed increased sensitivity to NaCl concentrations, i ndicating gamma-ray injury. The levels of aflatoxin produced by 2.0 kG y irradiated conidia of A. flavus decreased in the presence of 2, 4 or 6% NaCl, and the detoxification rate was 94.1, 100 and 100%, respecti vely, after 21 days of incubation at 28 degrees C compared with the ef fect of gamma-rays or sodium chloride alone.