Mycoflora and occurrence of aflatoxin B-1 and fumonisin B-1 during storageof Brazilian sorghum

The present study is a 1-year follow up of the mycoflora of 140 samples of Brazilian freshly harvested (10) and stored (130) sorghum, the levels of af latoxin and fumonisin contamination detected in the grains, and the prevail ing abiotic factors (grain moisture content, water activity, temperature, r elative humidity, and mean rainfall) at the time of sampling. The results s how a predominance of the genera Phoma (57.1%), Aspergillus (42.7%), Fusari um (25.0%), and Rhizopus (21.4%) and the presence of nine other filamentous fungi. Fusarium, Aspergillus, and Penicillium, the three most important ge nera in terms of toxicity, presented numbers of colony forming units per gr am of sorghum (CFU/g) that varied from 1 x 10(3) to 36 x 10(3), from 1 x 10 (3) to 295 x 10(3), and from 1 x 10(3) to 20 x 10(3) CFU/g, respectively. T he species most frequently found were Aspergillus flavus and Fusarium monil iforme. Of the total samples analyzed, 12.8% were contaminated with aflatox in B-1 (concentration mean 7-33 mu g/kg) and 74.2% with fumonisin B-1 (conc entration mean 0.11-0.15 mu g/g). This paper is the first report of the nat ural occurrence of aflatoxins and fumonisins in sorghum grain from Brazil.