Unveiling the metabolic mechanism of pesticide in food fermentation through metagenomics and metabolomics: A case study of β-cypermethrin in Pixian broad-bean paste.

Fermented foods contain less chemical pollutants, such as pesticide residues, than raw materials. In this study, using Pixian broad-bean paste as a model system, the pesticide degradation during food fermentation was comprehensively elucidated through metagenomic and metabolomics analyses. As a result, β-cypermethrin (β-CY) at 5 mg/kg was almost completely degraded, with a half-life of 6.1 d. β-CY caused flavor changes in fermented products, reducing esters and increasing ketones. Metagenomic analysis revealed that β-CY promoted bacteria phyla Bacteroidota, Pseudomonadota, and enriched the genes of xenobiotic degradation pathways, which is beneficial to its degradation. Microbial-metabolite correlation analysis identified Cyclobacteriaceae, Sulfurovaceae, FEN-1099 and Rhodocyclaceae as key drivers in the synthesis and metabolism of aromatic compounds following β-CY degradation during PBP fermentation. This dual mechanism offers a crucial theoretical foundation for understanding microbial community adaptability and β-CY detoxification in the process.