Microbial Detoxification of Residual Pesticides in Fermented Foods: Current Status and Prospects

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TL;DR

This review examines how fermentation by lactic acid bacteria (LAB) and other microorganisms can degrade residual pesticides in foods such as milk, yogurt, pickled vegetables, grains, wine, and meat. Microbial enzymes—particularly organophosphate hydrolases, phosphatases, and esterases—hydrolyze pesticides into less toxic compounds, with LAB strains like Lactiplantibacillus plantarum achieving up to 99.7% degradation of organophosphates in fermented products. The findings support microbial detoxification as a cost-effective strategy to reduce dietary pesticide exposure, though the exact metabolic pathways in food matrices remain incompletely characterized.

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**Background:** Pesticides are widely used in agriculture to improve crop yields, but residual amounts persist in food and pose health risks including neurological damage, endocrine disruption, gastrointestinal disorders, cancer, and death. Approximately 3 billion kg of pesticides are applied annually worldwide, with over 500 registered compounds. The European Food Safety Authority (EFSA) monitors pesticide residues, and maximum residue levels (MRLs) are legally regulated, though enforcement is weak in many developing countries. Physical and chemical detoxification methods (washing, peeling, boiling, ozonation) are only partially effective or expensive. Microbial detoxification during fermentation has emerged as a cost-effective alternative, with lactic acid bacteria (LAB) being the most promising group.

**Methods:** This is a narrative review summarizing published studies on microbial degradation of pesticide residues in fermented foods. The authors synthesized data from studies investigating organochlorines (OCPs), organophosphates (OPPs), pyrethroids, carbamates, neonicotinoids, and urea pesticides in milk, yogurt, pickled vegetables (kimchi, sauerkraut, olives), grains, sourdough, wine, fruit juices, tea, and meat. They also reviewed molecular mechanisms including enzymatic hydrolysis by phosphoric monoester hydrolases (EC 3.1.3), phosphoric triester hydrolases (EC 3.1.8), and esterases, as well as adsorption and co-metabolic degradation pathways.

**Key Results:** In milk and yogurt, starter cultures containing Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus, and yeasts achieved maximum reduction of total DDT after 7–10 days. Latilactobacillus sakei strain pro7 reached 95.1% biodegradation of DDT at 20 mg/kg. A probiotic mixture of L. acidophilus LA-5 and Bifidobacterium animalis subsp. lactis BB-12 reduced heptachlor by 36.6% after 14 days. LAB in skimmed milk decreased OPP concentrations by 7.0–64.6%, with L. delbrueckii subsp. bulgaricus increasing degradation rate constants by 18.3–133.3%. In kimchi, chlorpyrifos was reduced by 83.3% by day 3 and completely degraded by day 9, mediated by Leuconostoc mesenteroides WCP907, Levilactobacillus brevis WCP902, Lp. plantarum WCP931, and La. sakei WCP904. In sauerkraut and Mao-tofu, Lp. plantarum degraded 96.2–99.7% of OPPs after 42 hours and 79.7–99.5% after 6 days. Lp. plantarum strains from olive brine degraded 90–96% of chlorpyrifos and 24–53% of deltamethrin in three days. In black olive fermentation over 60 days, Lp. plantarum removed 61% deltamethrin, 68% dimethoate, and 50% imidacloprid. In corn silage, Lp. plantarum combinations reduced phorate by 24.9–33.4% over 10 weeks. During wheat fermentation, Lp. plantarum achieved 81% total degradation of pirimiphos-methyl. Saccharomyces cerevisiae degraded 21% of glyphosate within 1 hour during bread fermentation, and 46–70% of various pesticides during dough fermentation. When pesticide levels were 15 times above MRL, degradation rate constants increased by 594% for pirimiphos-methyl with S. cerevisiae and 469% for chlorpyrifos with Lp. plantarum. In wine, Oenococcus oeni reduced chlorpyrifos by 70%, dicofol by 40%, chlorothalonil by 35%, and procymidone by 25%. Coupled fermentation with S. cerevisiae and O. oeni decreased tebuconazole by 86%. In meat, Lp. plantarum and Micrococcus varians reduced DDT by 10% and lindane by 18% after 72 hours. At the molecular level, five OP hydrolases (OpdB, OpdD, OpdA, OpdE, OpdC) from Lev. brevis, La. sakei, Leuc. mesenteroides, and Lp. plantarum have been characterized, all containing the Gly-X-Ser-X-Gly motif typical of serine hydrolases. Alkaline phosphatase from Lacticaseibacillus casei 355 degraded dimethoate by approximately 50% in four hours. Lp. plantarum subsp. plantarum CICC20261 achieved 50–87% degradation of dimethoate, chlorpyrifos, methylparathion, and trichlorphon at 24 hours.

**Clinical Implications:** Microbial detoxification during fermentation offers a practical, low-cost strategy to reduce dietary pesticide exposure, particularly in regions with weak regulatory enforcement. Probiotic LAB strains not only degrade pesticides in food but may also mitigate ingested pesticides in the gastrointestinal tract through enzymatic degradation, adsorption, antioxidant activity, and enhancement of gut barrier function. Lp. plantarum BJ0021 alleviated endosulfan toxicity in rats, and Lacticaseibacillus rhamnosus GG and GR-1 reduced absorption of parathion and chlorpyrifos in Caco-2 intestinal epithelium models. However, the authors caution that the antioxidant properties of LAB require further validation, and the metabolic fate of toxic intermediates such as TCP (3,5,6-trichloro-2-pyridinol) and DETP (diethylthiophosphoric acid) in probiotic strains remains poorly understood. Future research should focus on elucidating complete degradation pathways, expanding LAB application to organochlorines, carbamates, and neonicotinoids, and developing starter cultures with enhanced detoxification potential.