Unveiling the Residual Characteristic, Processing, and Dietary Risk of Flonicamid and Acetamiprid in Sichuan Pepper Production: A Multisite Field Trial Research

Sichuan pepper, a pungent culinary spice, as well as a traditional medicinal plant, is widely used in Asian countries. Currently, pesticide combinations are still the most important tools for controlling insect pests to ensure the production of Sichuan pepper. However, there are limited data regarding the potential hazards posed by residues of these substances in Sichuan pepper products. In this study, a QuEChERS technique via UPLC-MS/MS for multianalysis of flonicamid and acetamiprid in fresh and dried Sichuan pepper was established with mean recoveries of 96–104%, relative standard deviations of ≤11%, and limits of quantifications of 0.01 mg/kg. A multisite field trial research was conducted to evaluate the persistence, processing factor, and dietary risk of flonicamid and acetamiprid in Sichuan pepper collected from four representative cultivation areas in China by the validated technique. The dynamic experiment indicated that flonicamid and acetamiprid degraded easily in Sichuan pepper with half-lives of 3.7–6.5 and 6.2–28.9 days, respectively. The residue concentrations of flonicamid and acetamiprid increased after the processing step with a processing factor higher than 1. The long-term dietary risk caused by residues of flonicamid and acetamiprid in Sichuan pepper is negligible, indicating that the application of these pesticides in Sichuan pepper cultivation was unlikely to pose adverse effects. Ultimately, in order to ensure food security, the maximum residue limits (MRLs) of flonicamid and acetamiprid were recommended at 1 and 2 mg/kg for dried Sichuan pepper, respectively, based on residue chemistry data and dietary assessment results. This study offers insights into the appropriate scientific application of the new commercial formulation in Sichuan pepper and contributes valuable data for the establishment of MRLs for flonicamid and acetamiprid in the future.