Introduction
Accurate estimation of human exposure to chemical residues, such as veterinary drugs, in food is essential for ensuring food safety. Current monitoring practices primarily focus on unprocessed foods, comparing residue levels with regulatory maximum residue limits (MRLs). However, comprehensive exposure assessment requires the inclusion of composite and processed foods that we normally eat. In this study, we developed a refined conceptual method incorporating a novel reverse-yield factor (RF) to disaggregate composite foods into representative raw primary commodities, along with processing factor (PF) to account for changes in residue concentrations during food processing.

Methods
We applied the refined method to data from nationwide dietary surveys conducted in Japan during fiscal years 2005–2007 (89,798 records) and 2016–2020 (76,863 records). Acute exposure to veterinary drug residues detected in raw agricultural commodities was assessed by comparing estimated intakes with the corresponding Acute Reference Dose (ARfD) values reported. For conservative estimation, we used the highest concentrations of residues detected in Atlantic salmon, including emamectin benzoate, oxytetracycline, sulfamonomethoxine, and hydrocortisone.

Results
The highest estimated acute exposure was 0.00220 mg/kg bw/day (7.3% of the ARfD value) for oxytetracycline among children aged 1–6 years who consumed imported Atlantic salmon. For domestically produced Atlantic salmon, the highest exposure was 0.000176 mg/kg bw/day (0.9% of the ARfD value) for emamectin benzoate in the same age group. Other age groups examined included adults (7–64 years old), women of childbearing age (15–50 years old), seniors (over 65 years old), and the general population (over 1 year old).

Conclusions
The estimated acute exposures from Atlantic salmon consumption were well below their respective ARfDs, suggesting minimal health risk from the detected residues for the Japanese population. This novel approach, integrating RF and PF, enhances the accuracy of dietary exposure assessments for chemical residues in foods.