Residue levels, household processing evolution, and risk assessment of chlorothalonil, SDS-3701, metalaxyl, and dimethomorph in Dendrobium officinale Kimura et Migo.

Dendrobium officinale, a minor crop with medicinal and edible value, is increasingly consumed by people, but the pesticide residues on it have received little attention. In this work, field trials were conducted under good agricultural practice conditions to investigate the residues of chlorothalonil, SDS-3701, metalaxyl, and dimethomorph in D. officinale; then the evolution of these pesticides after household processing was studied. The results indicated that chlorothalonil, SDS-3701, metalaxyl, and dimethomorph were 2.41-30.12, 0.20-1.23, 0.07-0.80, and 0.19-7.90 mg kg , respectively, in stems at recommended preharvest interval (30 days). Washing and soaking removed the pesticides in fresh stems with processing factors 0.41-1.14 and 0.12-1.13, respectively. In the brewing test, the transfer rates of pesticides in dry stems decreased from the first time (4.27-95.40%) to the third time (3.89-15.57%). Intake risk assessments were also conducted, and the risk quotients were no more than 27.02% for all compounds in different samples, which indicated acceptable risks for consumers. As effective risk-reducing home-processing methods, washing, soaking, and multiple brewing were suggested in this work, hoping to help consumers with diet safety.