A Saliva-Based Migration Approach for Assessing Oral Exposure to Contaminants from Paper and Plastic Drinking Straws

Migration testing of food-contact articles relies mainly on content analysis or immersion in water or food simulants, which may not reflect exposure when articles are held in the mouth. A saliva-based immersion approach reflecting actual use was applied to drinking straws. Six paper and three plastic straws were cut into thirds and immersed in 5 mL of human saliva for 10, 30, and 60 min, with a straw-free blank for each of three saliva collections. Twenty metals, six phthalates, three bisphenols, and 20 per- and polyfluoroalkyl substances (PFAS) were quantified, increases relative to the same-set blank were classified, and single-use exposures were compared with health-based guidance values. The approach detected the release of matrix-derived elements (manganese, barium, and molybdenum from a pink straw) and small amounts of lead and antimony from paper straws, with exposures ≤0.02% of guidance values. Among PFAS, only perfluorodecanoic acid increased, whereas bisphenol A, undetected in all blanks, increased sporadically in both materials, reaching up to 120% of the tolerable daily intake of the European Food Safety Authority for a 20 kg child. Although standardized methods are lacking, saliva-based migration testing may provide a more realistic basis for exposure assessment of mouth-contact articles than conventional tests.