Beyond direct contact: Chemical migration from external printed components of tea packaging into infusions assessed by UPLC-IM-QTOF analysis

The safety of food packaging has traditionally focused on materials in direct contact with food, often neglecting the potential contribution of printed external components. This study investigates the migration of chemical substances from non-food-contact elements of tea bag packaging—such as printed labels and external wrappers—into tea infusions prepared under realistic conditions. Migration was simulated by immersing both tea bags and their associated printed materials in boiling water. Extracts were analyzed using ultra-performance liquid chromatography coupled with ion mobility–quadrupole time-of-flight mass spectrometry (UPLC-IM-QTOF), enabling sensitive and multidimensional profiling of known and unknown migrants. Concentrations of identified substances ranged from 5.7 to 369 ng/g, with compound-specific detection limits spanning 1.1–12.3 ng/g. Principal Component Analysis (PCA) revealed that ink and varnish formulations contributed significantly to the variation in migration profiles among brands, despite identical tea compositions. Compounds such as hexadecyl methacrylate and benzophenone were uniquely associated with specific packaging types, while ubiquitous substances like acetyl tributyl citrate and erucamide indicated common ink usage. Notably, several potential endocrine disruptors were detected, although all migration levels remained below current regulatory limits. These results emphasize the importance of including all packaging layers in safety assessments and demonstrate the utility of UPLC-IM-QTOF for comprehensive non-targeted migration analysis. • Chemical migration occurs from printed tea packaging into infusions. • UPLC-IM-QTOF enables detection of both known and unknown migrants. • Inks and varnishes drive migration variability among similar tea brands. • Endocrine disruptors detected, though below regulatory migration limits. • Study highlights the need to assess all packaging layers, not just contact.