Screening, residue dissipation and risk assessment of 54 pesticides in winter jujube under different harvesting and storage conditions

The effects of different storage time, storage temperature and harvesting period on pesticide residues in different circulation stages of winter jujube were studied by using GC-MS-MS and LC-MS-MS. And the risk assessment for the safe application of 12 kinds of pesticides in winter jujube was conducted. The results showed that, among the 54 pesticides tested, 12 of them were detected in the winter jujube samples, and the overall detection rate was 22.6%. No banned or highly toxic pesticides were detected. At room temperature, the half-life of carbendazim was 4.8-6.0 days, the half-life of pentazolidol was 4.9-11.2 days, and the half-life of phenyleocycloazole, imidacloprid, and pyrizoyl ester were 10.0 days, 2.8 days, and 6.9 days, respectively. Under the condition of 0 ℃, the half-life of carbendazim was 5.5-9.4 days, the half-life of pentazolidol was 14.1-57.8 days, and the half-life of phenyleocycloazole and imidacloprid were 8.6 days and 10.5 days, respectively. The dissipation of 9 pesticides in winter jujube at different harvesting stages was obvious. The dissipation of fresh jujube at commercial harvesting stage was higher than 50%. Studies on the risk assessment of chronic and acute dietary exposure to pesticide residues in winter jujube after different harvest and market procurements showed that the risk of dietary intake was low and acceptable, except for carbendazem. The chronic ingestion risks of carbendazim in winter jujube in different circulation periods (market procurement) were unacceptable.