Mycoflora and aflatoxins in a west African corn-groundnut based convenience food

A total of 14 fungal species, mostly toxigenic, were isolated from 50 samples of 'donkwa' snack obtained from 16 producers. All of the isolates recorded substantial growth, though at varying rates, on the 2% snack agar provided. They also induced a reduction in the oil and an increase in free fatty acids of the substrate suggesting their participatory roles in deterioration. Most of the snack samples analysed contained initial amounts of aflatoxins above the 'safe' permissible level (30 ppb). The initial toxin levels increased substantially with storage time under 79.5, 89.5 and 100% ambient relative humidities but increased only slightly when samples were kept at 71% relative humidity. Almost constant toxin levels were recorded throughout the study period under 51% relative humidity. Accumulation of aflatoxin B1 in samples was most enhanced at 89.5% relative humidity. Comparatively, greater amounts of aflatoxin B1 accumulated under all conditions than the amounts recorded for aflatoxin G1.