Processing factors of several pesticides and degradation products in carrots by household and industrial processing

To quantify the effect of household and industrial processing on the pesticide residues, carrots (Daucus carota) were sprayed during cultivation with three fungicides (boscalid, difenoconazole and tebuconazole), two insecticides (chlorpyrifos and dimethoate) and one herbicide (linuron). The most concentrated formulations were applied pursuant to Good Agricultural Practices, to ensure sufficiently high levels of residues, The subsequent processing conditions were established to correspond as close as possible to the actual conditions that are normally used in industrial practice. The effects of household and industrial processing on the levels of the six pesticide residues and eight associated degradation products were quantified. The washing step allowed decreasing the concentration of residues for all pesticides up to ~ 90%. It was the most effective step to remove pesticide residues from carrots. The second process, peeling, results in a reduction comparable to washing. The blanching step, combining heat with a large quantity of water, enhanced the elimination of residues (maximum 50%). After cutting and washing, the residual concentrations were below 5 ppb. However it was observed that the level of pesticide residues was not reduced by microwave cooking. The pesticide residues remaining after previous processing, except difenoconazole, were decreased by sterilization. The cumulative processes allowed the elimination of minimum 90% of pesticide residues. Degradation products, investigated in this study, were not detected.