PFAS in Fast Foods with Hot-Contact to Food-Contact Materials: Occurrence, Packaging Influence, and Risk Priority

Despite growing concern over per- and polyfluoroalkyl substances (PFAS), evidence for packaging-driven dietary exposure under hot-contact scenarios remains limited, especially in China's rapidly expanding takeout market. Here, we conducted a survey of fast foods (n = 150) and corresponding food-contact materials (FCMs, n = 150) across Chinese markets, quantifying 32 legacy and emerging PFAS. PFAS were detected in all foods (range: 0.01-79.4 ng/g; median: 3.45 ng/g) and FCMs (0.01-205 ng/g; 3.88 ng/g). Paper-FCMs showed the highest PFAS levels among different FCM categories and exhibited industry-specific patterns. Food PFAS profiles mirrored those of paired FCMs, with significant correlations for several dominant congeners (p < 0.05), indicating migration contributions. Moreover, migration patterns were jointly influenced by PFAS physicochemical properties (e.g., log K_OW, functional moieties), FCM texture, and food composition. Clear differences between leading and smaller brands were observed, with smaller brands exhibiting higher PFAS burdens in fast foods (p < 0.05). Notably higher PFAS concentrations were identified in soup-based instant foods. A controlled experiment demonstrated 3.1-26-fold higher PFAS concentrations in instant foods prepared in original paper packaging than in glass containers, largely driven by 6:2 FTS, which accounted for 88.3% of the total ∑₃₂PFAS increment. Integrated multifactor prioritization revealed several emerging PFAS of particular concern, especially given their expanding use in FCMs. These findings highlight hot-contact packaging as a non-negligible exposure source and call for enhanced surveillance of emerging PFAS in fast-food supply chains.