Traditional Fermentation Amplifies PFAS Bioaccessibility: Defining Fermented Fish Products as an Unrecognized Source of Dietary Exposure

Per- and polyfluoroalkyl substances (PFAS), as a class of persistent organic pollutants, are well-characterized environmental and human health threats; however, their behavior in food systems, particularly during fermentation, remains poorly understood. Here, we show that traditional fermentation significantly enhances the PFAS bioaccessibility. Through a 300 day model fermentation system, we observed near-complete release of several major PFAS congeners. While microbial transformation of the PFAS precursor of N-ethyl perfluorooctane sulfonamide (N-EtFOSA) was observed, persistent congeners of perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) remained unaffected during microbiome restructuring. We demonstrate that matrix degradation and microbial activity synergistically modify the PFAS binding states. In silico modeling reveals a shift in bioaccessibility determinants from specific binding to partitioning behavior, establishing that fermentation liberates PFAS via two key pathways: microbial degradation of structural components, releasing bound contaminants and altered PFAS partitioning during digestion. Our findings establish fermentation as a previously unrecognized amplifier of dietary PFAS exposure, with substantial implications for food safety and public health, especially in populations with high consumption of traditionally fermented products.