Migration of organic and inorganic antimicrobials from antimicrobial-labeled food packaging and probabilistic risk assessment implications

Antimicrobial-labeled food contact materials may pose potential health risks due to the migration of antimicrobial substances. Most previous studies examined fewer than ten samples, investigated only a limited number of antimicrobial agents, and rarely considered both organic and inorganic antimicrobials. This study assessed the migration and health risks of 47 organic and 3 inorganic antimicrobials from 171 polymer-based food contact materials. Tested materials included polyethylene (PE), polypropylene (PP), thermoplastic polyurethane (TPU), melamine-formaldehyde resin, polyethylene terephthalate (PET), and polylactide (PLA). Representative antimicrobial-labeled food packaging films were characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), oxygen transmission rate (OTR), and water vapor transmission rate (WVTR). Among organic antimicrobials, zinc pyrithione was detected in three PE cutting boards and one PLA cutting board, with migration levels up to 1091 μg/L. Triclosan appeared only in one TPU cutting board under fatty food conditions, at 225 μg/L. Inorganic antimicrobials were detected more frequently, with migration of about 1 μg/L for silver, 43 μg/L for zinc, and 35 μg/L for copper under acidic conditions. Zinc pyrithione raised concern in the Tier 1 screening-level risk assessment due to its high migration level. However, a refined Tier 2 probabilistic risk assessment indicated no significant risk, even under upper-limit exposures. Triclosan and all three inorganic antimicrobials were determined to be safe. Overall, no significant health risks were identified from the tested food contact materials.