Evaluation and simulation of silver and copper nanoparticle migration from polyethylene nanocomposites to food and an associated exposure assessment.

Silver nanoparticles (nanosilver) and copper nanoparticles (nanocopper) exhibit antimicrobial activity and have been incorporated into polymers to create antimicrobial packaging materials. Their use in conjunction with food has caused concerns regarding the potential risk of particle migration, resulting in human exposure to nanoparticles. A migration experiment was carried out to investigate the effect of time and temperature on the migration of nanosilver and nanocopper particles from polyethylene (PE) nanocomposites to boneless chicken breasts. Migration of silver ranged from 0.003 to 0.005 mg/dm², while migration of copper ranged from 0.024 to 0.049 mg/dm², for a set of four different scenarios representing typical storage conditions. Effects of time and temperature were not significant (p > 0.1). A migration and exposure model was developed on the basis of mathematical relationships defining migratability and subsequent migratables using the Williams-Landel-Ferry equation for time-temperature superposition. The results of the model accurately predicted the nanosilver levels detected in the laboratory migration tests (R values ranging from 0.43 to 0.99); however, the model was less accurate in predicting nanocopper levels (R values ranging from 0.65 to 0.99), probably because of the highly variable background levels of copper observed in the real food matrix. The 95th percentile of the simulated human exposure to nanosilver based on laboratory experimental results of four scenarios ranged from 5.89 × 10⁻⁵ to 8.9 × 10⁻⁵ mg kg(bw)⁻¹ day⁻¹. For the measured migration of copper under the same storage conditions, the exposure ranged from 2.26 × 10⁻⁵ to 1.17 × 10⁻⁴ mg kg(bw)⁻¹ day⁻¹. This study highlights the potential migration of nanoparticles from PE composite packaging to a food material and the potential for simulation models to accurately capture this migration potential; however, variable background levels of copper in the food matrix can make prediction more difficult for trace migration of nanocopper.