Control of Fusarium moulds and fumonisin B1 in seeds by gamma-irradiation

The distribution of naturally occurring Fusarium moulds producing fumonisin B1 in seeds was determined. Fusarium infection of seed samples ranged from 10% to 60%, Fusarium moniliforme was the predominant species. Fusarium counts in wheat seeds were 8.1 × 104 CFU/g, 6.3 × 106 CFU/g in maize and 4.8 × 103 CFU/g in barley. Wheat, maize and barley seeds naturally contaminated with varying levels of fumonisin B1 1.4–5.8, 8.0–13.8 and 0.1–0.5 μg/g, respectively. F. moniliforme and Fusarium proliferatum were major Fusarium contaminants producing fumonisin B1. The effect of gamma irradiation on Fusarium moulds and levels of fumonisin B1 was also determined. The viable counts of Fusarium in seeds decreased by increasing the radiation dose levels and the growth of Fusarium spp. was inhibited at 4.0 kGy for barley and 6.0 kGy for wheat and maize. Application of radiation dose at 5 kGy inactivated fumonisin B1 by 96.6%, 87.1% and 100% for wheat, maize and barley, respectively, and a dose of 7 kGy was sufficient for complete destruction of fumonisin B1 in wheat and maize.