The potencies of three microorganisms to dissipate four organophosphorus pesticides in three food materials during traditional fermentation

Edible yeast, Lactobacillus plantarum and Mucor were used in traditional fermentation of three food materials wheat dough, pickled Chinese cabbage and Mao-tofu, respectively. The potencies of yeast, lactic acid bacteria and Mucor to promote the degradation of four organophosphorus pesticides (OPPs) including chlorpyrifos, dichlorvos, phorate and trichlorphon were studied, via detection of OPP residues by gas chromatography and calculation of OPPs degradation rate constants by a first-order reaction model. Analysis results showed that about 16.6-31.8, 96.2-99.7 and 79.7-99.5 % of the OPPs were removed from these food materials after fermentation times of 5 h, 42 and 6 days, respectively. Dichlorvos and phorate in all cases were the most labile and stable pesticides, as they gave the highest and lowest degradation rate constants, respectively. Inoculation of yeast, L. plantarum and Mucor resulted in the investigated samples enhanced OPPs rate constants by 82-270, 115-219 and 115-224 %, respectively. The OPPs in wheat dough and Mao-tofu showed 4-12 folds greater rate constants than those OPPs in pickled Chinese cabbage. It is concluded that these microorganisms are able to enhance OPPs dissipation in these fermented food materials, and yeast and Mucor are more potent than L. plantarum to degrade OPPs.