Impact of washing and cooking on the dietary exposure risk of chlorfenapyr and beta-cypermethrin residues in mustard green and non-heading Chinese cabbage

To clarify the impact of different washing and cooking approaches on the dietary exposure risks of two fat-soluble pesticides (chlorfenapyr and beta-cypermethrin) in mustard green (Brassica juncea (L.) Czern.) and non-heading Chinese cabbage (Brassica chinensis L.), five common cleaning approaches (edible salt water, edible baking soda water, rice-washing water, tap water, edible vinegar aqueous solution) were used to clean the mustard green and non-heading Chinese cabbage in a simulated Chinese kitchen, and four cooking approaches (boiling, steaming, frying, and pickling) were used to process the samples. The residues of chlorfenapyr and beta-cypermethrin in samples before and after kitchen processing were determined using QuEChERS sample preparation and GC-MS/MS and UPLC-MS/MS detection. By estimating the processing factors (PF) and the changes in exposure doses and the contributions to long-term dietary exposure risk (ADI_i%) and short-term dietary exposure risk (%ARfD) to three representative Chinese populations (children, women of childbearing age, and the general population), the role of washing and cooking in reducing dietary exposure risk and in reducing uncertainty in dietary exposure risk assessment were estimated. The results showed that, edible baking soda water and the edible salt water had the best removal rates for mustard green and non-heading Chinese cabbage, and it was significantly better than the washing with tap water. After washing and cooking, the processing factors (PF_Total) in mustard green were 0.06-0.24 for chlorfenapyr and 0.04-0.11 for beta-cypermethrin, and those in non-heading Chinese cabbage were 0.05-0.21 for chlorfenapyr and 0.06-0.11 for beta-cypermethrin. The estimated exposure doses of these 2 pesticide residues were reduced by 76%-96% using washing and cooking processing. The study showed that routine kitchen processing can differentially reduce the risk of long-term and short-term dietary exposure of both chlorfenapyr and beta-cypermethrin residues to representative populations in China. Specifically for mustard green and non-heading Chinese cabbage, kitchen processing resulted in %ARfD < 100% for the residue of beta-cypermethrin, but not for the residue of chlorfenapyr.