Fate Of Pesticide Residues In Edible Agricultural Products By Food Processing And Storage

People often care more about the risk posed by pesticide resiude in the Raw AgriculturalCommodities (RAC) during the agriculture commodities quality safety evaluation, while ingore theimpact caused by the processing and storage procedure, so it is important for us to study the dynamicvariation of the pesticide residue during the processing and storage procedure, otherwise the amount ofunit exposure of pesticide of people from their food may be unprecise and misleaded. This paperchooses the rice, tomato, apple and beer as the main object, to study the dynamic variation of thepesticide residues during their processing and storage procedure. The main study results are presented asfollow:1. The degradation of acephate and its metabolite methamidophos during different stages ofcommercial processing, homing processing, and storage was assessed. Acephate and methamidophosmostly remained in rice hull fractions, and hulling significantly reduced acephate and methamidophos inrice. Commercial processing and home processing caused significant reduction in brown rice. Extendingwashing time and adding a small amount of soda into the washing solution can efficiently eliminateacephate and methamidophos residues. The stability of acephate and methamidophos in polished ricewas studied at different storage intervals, and the methamidophos was found to be more persistent thanacephate.2. The effects of different steps in canned tomato paste production on difenoconazole levels wereinvestigated. Results showed that washing and peeling process reduced the amount of residue by99%,whereas homogenization, simmering, and sterilization process had little effects on the removal ofdifenoconazole residue. The tomato seeds were found free of difenoconazole after homogenization,which was mainly present in the tomato puree. The mean reduction of difenoconazole in tomato sampleafter sterilization is13.6%.3. The effect of home processing (washing, peeling, coring and juicing) on residue levels ofchlorpyrifos, beta-cypermethrin, tebuconazole, acetamiprid and carbendazim in apple segments wasinvestigated. The results indicated that the pesticide residue levels in the apple peel and core werehigher compared with in the apple flesh. Chlorpyrifos, beta-cypermethrin and tebuconazole wereconcentrated in the apple pomace during juicing process. However, residues of acetamiprid andCarbendazim were exceptions. The apple pomace was found free of acetamiprid, which was mainlypresent in the apple juice. The effect of commercial processing of apple juice concentrate on pesticideresidues was also investigated, sterilization could further reduce chlorpyrifos and beta-cypermethrinresidue levels, the reduction were66%and51%, the elimination of tebuconazole, acetamiprid andcarbendazim is in the range of19～29%after sterilization. Sterilization could reduce some unstablepesticides residues to a certain degree. The residue levels of five pesticide residues in apple juiceconcentrate were concentrated. 4. The fate and behaviour of two insecticides (dichlorvos and malathion) during different stages ofbeermaking (milling, mashing, filtrating and fermenting) was assessed. Milling had little effects on theremoval of dichlorvos and malathion residue, with the processing factor0.93. After mashing, asubstantial fraction was removed with the spent grains in all cases, the levels of dichlorvos were higherthan malathion in wort. Finally, The beer was found free of dichlorvos and malathion after fermenting.