Mitigation of Field-Derived Pesticide Residues in Wheat Flour through Combined Partial Germination and Lactic Acid Bacteria Fermentation

The persistence of pesticide residues in cereal grains represents a critical issue for food safety. In this field study, wheat grains were treated with selected herbicide, fungicide, and insecticide active ingredients to assess residue occurrence under different application timings. No detectable residues were observed following conventional application schedules, whereas late and/or repeated applications resulted in measurable contamination by the herbicide clopyralid and the fungicides epoxiconazole, pydiflumetofen, and azoxystrobin. The potential of a combined germination–lactic acid fermentation strategy to mitigate pesticide residues in contaminated wheat was subsequently investigated. Germination alone induced partial reductions of clopyralid, epoxiconazole, pydiflumetofen, and azoxystrobin, likely through enzymatic activation and oxidative processes, as well as microbiota-mediated transformations. Subsequent controlled fermentation of germinated flours with selected lactic acid bacteria (Lactiplantibacillus plantarum, Levilactobacillus brevis, Pediococcus pentosaceus, Limosilactobacillus fermentum) resulted in substantial additional degradation, with complete removal of azoxystrobin and significant reductions of epoxiconazole (up to 55%) and pydiflumetofen (up to 34%). Non-germinated flours fermented under the same conditions did not exhibit significant pesticide degradation, highlighting the critical role of germination in preconditioning the grain matrix. Mechanistic insights suggest that enhanced hydrolytic and oxidative reactions, supported by microbial metabolism and cofactor availability, contribute to residue reduction. Beyond proper field management, the integrated germination–fermentation process represents a sustainable and food-compatible strategy to mitigate pesticide residues in wheat while preserving nutritional quality, thereby enhancing the safety of whole-grain products.