Contamination of fermented foods in Nigeria with fungi

This study assessed the safety and quality of some fermented foods in Nigeria. Cluster sampling was used to obtain different fermented foods: maize gruel (ogi), locust beans (iru), sorghum meal (ogi baba), dried locust beans (dried iru), African oil bean seed (ugba) and melon (ogiri) from Southwest Nigeria. Moisture content, Total Titratable Acidity, pH, and fungal diversity within each sample were determined. The identity of the isolates was established through macroscopic, microscopic and molecular biology means. The moisture content and pH of analysed samples ranged from 12 to 56% and 3.60 to 8.08, respectively. The overall data on the mycobiota of the fermented foods revealed that total fungal loads of ugba and ogiri were 1.05 × 10⁵ and 7.9 × 10⁵ cfu/g, respectively. Generally, fungal isolates belonged to 17 genera including Aspergillus, Fusarium, Candida, Saccharomyces and Penicillium. The dominant fungi detected were A. flavus and all analysed samples were contaminated with F. verticillioides except for ogi baba. The study led to the discovery of new fungal strains and previously unreported fungal species in the selected fermented foods. The analysed fermented foods were highly contaminated with different fungal species that could potentially be toxigenic in producing various types of mycotoxins.