Toxicity evaluation and prioritization of recycled plastic food contact materials using in silico tools

This study assessed the toxicity of virgin and recycled plastic food contact materials (FCMs) at various recycling stages, migrated in four food simulants (water, 20 % ethanol, 4 % acetic acid, and n-heptane), using cytotoxicity and high-content screening (HCS) bioassays. Toxicity was correlated with migrating substances identified through chemical analyses, and samples were ranked by toxicity priority. Recycled polyethylene terephthalate (rPET) and 20 % ethanol exhibited the highest reduction in cell viability, whereas virgin PET (vPET) showed even lower viability. Pellets did not trigger oxidative responses in HepaRG and HK-2 cells; however, bales and flakes affected their cell morphology and mitochondrial function. rPET-flake migration in 4 % acetic acid was most toxic to HepaRG cells, while rPET-bale migration in 20 % ethanol and rPP-flake migration in water were most toxic to HK-2 cells. Nonetheless, the negative effects on cell viability and HCS parameters were mostly mitigated at the final pellet stage. In HepaRG cells exposed to 4 % acetic acid, antimony negatively correlated with cell viability and positively with cellular area, indicating its role in rPET-induced necrosis. ToxPi ranking identified vPET migration in n-heptane and water as top priorities given the nephrotoxic risks. This study emphasizes refining recycling methods and testing plastics to minimize FCM cytotoxicity.