Mycoflora and aflatoxin/fumonisin production by fungal isolates from freshly harvested corn hybrids

The mycoflora of 3 hybrids of freshly harvested corn grains collected from three regions of the state of Sao Paulo, Brazil (Assis, Capao Bonito and Ri beirao Preto) was investigated. A total of 66 samples were analyzed focusin g on the influence of abiotic factors (moisture content, water activity, te mperature and rainfall) on both the prevalence of Aspergillus flavus and Fu sarium moniliforme, and the ability of these genera isolates to produce afl atoxins and fumonisins, respectively. In the three surveyed regions, the fu ngal population comprised mainly Fusarium spp., Penicillium spp., Aspergill us spp. and 2 others filamentous fungal genera, which were isolated from co rn kernels showing water activity of 0.30 to 0.99 and moisture content of 5 .0% to 20.2%. Among the genera Fusarium and Aspergillus, the most frequent species were F. moniliforme and A. flavus, respectively. Concerning the tox igenic potential of F. moniliforme, all isolated strains (40) produced fumo nisins at 20 mug/g to 2168 mug/g (FB1) and/or 10 mug/g to 380 mug/g (FB2). From the 10 A. flavus isolates, 6 strains (60.0%) produced aflatoxins at 61 5 mug/kg to 30.750 mug/kg (AFB(1)) and/or 11 mug/kg to 22 mug/kg (AFB(2)).