Mycotoxin Occurrence and the Influence of Fermentation and Storage Practices in Traditional Nigerian Fermented Foods: A Systematic Review

<ns5:p>Globally, mycotoxins have been identified as emerging toxins of concern and have a major impact on agriculture, humans, and animals. In Nigeria, mycotoxin occurrence in traditional fermented foods is a significant food safety concern since many staple foods are subjected to several fermentation and preservation processes. This systematic review aims to synthesize existing evidence on the occurrence of mycotoxins in traditional fermented foods and to evaluate the influence of fermentation processes and storage conditions on mycotoxin dynamics and food safety. The systematic review was carried out using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The inclusion criteria for the review were full length original research manuscripts published in peer-reviewed journals/conferences or postgraduate thesis/dissertations between 2010–2025 and conducted in Nigeria. Also, for inclusion, studies must report climatic impacts on fermented food storage, mycotoxin occurrence during fermented food production and storage. Findings from the systematic review revealed widespread occurrence of mycotoxins in traditional Nigerian fermented foods. The review also revealed the modulatory effects of fermentation and storage practices on mycotoxin levels. Evidence from studies reveals the potential of controlled fermentation with probiotic microorganisms in mycotoxin reduction. The study further revealed that although controlled fermentation can greatly reduce the levels of certain mycotoxins with probiotic strains, it could also facilitate co-occurrence of multiple mycotoxins due to fungal survival under nutrient-rich fermentation substrates. Apart from fermentation process, some other factors (fermentation substrates, storage practices, post-processing activities, open-market distribution, unhygienic handling) were also implicated to significantly increase mycotoxin levels. Overall, the reviewed studies showed although traditional fermentation can reduce mycotoxin levels, that reduction is not sufficient for total degradation, especially under suboptimal storage or high contamination scenarios.</ns5:p>