In Situ Fusarium Mycotoxin Mitigation During Wholegrain Wheat Flour Fermentation with Sourdough Lactic Acid Bacteria and Further Insights into Reduction Mechanisms

Fusarium mycotoxins are major contaminants of cereal-based products, yet effective clean-label mitigation strategies are still limited. Although lactic acid bacteria (LAB) have been extensively investigated as biological tools for mycotoxin reduction, evidence is largely based on in vitro studies. Here, nineteen LAB strains representative of sourdough microbiota were screened for their ability to reduce deoxynivalenol (DON) in wholegrain wheat dough. Pronounced strain-dependent differences were observed, leading to the selection of Lactiplantibacillus plantarum 1A7, Limosilactobacillus fermentum 10B, and Pediococcus pentosaceus I76 for further evaluation against a broader panel of Fusarium regulated and emerging mycotoxins, including modified DON derivatives, moniliformin, and enniatins. After 48 h of fermentation, with LAB populations reaching approximately 9 log CFU g−1, the selected strains achieved comparable reduction efficiencies across multiple analytes, decreasing mycotoxin levels by approximately 50% and lowering DON concentrations from 1270 µg kg−1 to below the European regulatory limit of 600 µg kg−1 for cereal milling products. To gain insight into the mechanisms involved, fermentations were performed using both viable and heat-inactivated cells. The lower reduction efficiency observed with inactivated cells was consistent with a contribution of cell wall-mediated adsorption, although additional contributions from LAB metabolic activity cannot be excluded. Overall, sourdough LAB effectively reduced multiple mycotoxins in a complex cereal matrix, with the observed effects indicating a reduction in extractable mycotoxin levels without providing conclusive evidence of detoxification. These findings provide new insights into LAB–mycotoxin interactions and support fermentation-based strategies for mycotoxin mitigation in wheat-based foods.