Residual Characteristics and Processing Factors of Flubendiamide and Tebufenozide in Rice and Its Processed Products

This study aimed to evaluate residue changes in flubendiamide and tebufenozide during the processing of whole grain into milled rice, cooked rice, and rice cake, and to calculate their processing factors (PFs). For the processing study, pesticides were applied at three times the recommended rate based on Korea's good agricultural practice (GAP), and processed products were prepared using conventional methods. Residual pesticide analysis was performed using a modified QuEChERS method and LC-MS/MS. The residue analysis method was validated based on parameters including LOQ, linearity, and accuracy at the LOQ, 10LOQ, and MRL levels, with the LOQ set at 0.01 mg/kg for all samples. During milling, which removes the hull, more than 90% of the pesticide residues were eliminated. Additional reductions exceeding 50% were observed during cooking and rice cake processing. All PFs, except for those in the hulls, were less than 1, indicating that processing reduces pesticide levels. Despite the use of threefold the GAP rate, the %ADI values for all processed products remained below 1%, suggesting negligible dietary risk. These findings provide scientific evidence supporting the safety of processed rice products regarding pesticide residues and highlight the importance of considering processing effects in dietary exposure assessments.