Although it is not currently authorized for use in the United States, silver nanoparticles (AgNPs) in polymeric food packaging, could potentially control the growth of microorganisms on the food packaging. Before these materials can be used as food contact materials in the United States, data on the migration of Ag into foods would be required as part the safety evaluation of food contact material containing Ag. It is therefore crucial to evaluate Ag transport mechanisms in different types of Ag-containing materials to better understand how Ag migration kinetics relate to the initial form of Ag in the polymer. In this study, we investigated the release of Ag from polymer nanocomposites (PNCs) incorporating Ag zeolite (Ag/Y), specifically examining how the form of Ag influences its release behavior. We first manufactured two families of Ag/Y/LDPE PNCs: one incorporating ionic Ag (Ag⁺) and one incorporating AgNPs, each with similar initial Ag concentrations. Then, we assessed Ag migration out of these PNCs and into food simulants under accelerated room temperature storage conditions. Notably, the Ag⁺/Y/LDPE PNC film exhibited a higher release of Ag compared to the AgNP/Y/LDPE PNC film, suggesting a lower fraction of readily releasable Ag in the latter film. Ag migration from AgNP/Y/LDPE PNC film was 12.506 ± 2.307 ng cm⁻² in water, 8.596 ± 1.795 ng cm⁻² in a 9 wt % sucrose solution to 23.979 ± 2.233 ng cm⁻² of packaging surface area in Squirt (a citrus-flavored, sweetened beverage) during 10 days of storage at 40 C. In contrast, Ag migration from Ag⁺/Y/LDPE PNC films were measured at 56.655 ± 3.956, 65.645 ± 11.017, and 104.545 ± 6.375 ng cm⁻² of packaging surface area in water, sucrose solution, and Squirt drink, respectively. Surface characterization techniques, including Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), and surface potential mapping, revealed the presence of exposed zeolite particles on the surface of the films, suggesting that direct desorption of Ag played a dominant role in determining the Ag release from these Ag/Y/LDPE PNC films.

Timothy Duncan

US Food and Drug Administration

Appearances