Occurrence of Fusarium species and mycotoxins in nepalese maize and wheat and the effect of traditional processing methods on mycotoxin levels

Maize (Zea mays) and wheat (Triticum aestivum) collected in the foothills o f the Nepal Himalaya Mountains were analyzed for Fusarium species and mycot oxins: fumonisins, nivalenol (NIV), and deoxynivalenol (DON). Predominant s pecies were Gibberella fujikuroi mating population A (F. moniliforme) in ma ize and F. graminearum in maize and wheat; G. fujikuroi mating population D (F. proliferatum), F. acuminatum, Ij: avenaceum, F. chlamydosporum, F. equ iseti, F. oxysporum, F. semitectum, and F. torulosum were also present. Str ains of G. fujikuroi mating population A produced fumonisins, and strains o f F. graminearum produced NIV or DON. By immunoassay or highperformance liq uid chromatography, fumonisins were > 1000 ng/g in 22% of 74 maize samples. By immunoassay or fluorometry, NIV and DON were,1000 ng/g in 16% of maize samples but were not detected in wheat. Fumonisins and DON were not elimina ted by traditional fermentation for producing maize beer, but Nepalese rura l and urban women were able to detoxify contaminated maize by hand-sorting visibly diseased kernels.