In a new study published online on April 20, 2015 in the peer-reviewed journal Food Additives & Contaminants: Part A, researchers from the U.S. Food and Drug Administration (FDA) and the U.S. Consumer Product Safety Commission evaluated migration of silver nanoparticles (NPs) from seven food contact materials (FCMs). The products were purchased within the U.S. as well as internationally. The FCMs were characterized for both the type of polymer and the presence of total and nanoparticulate silver. Ntim and colleagues measured silver migration from the FCMs under various conditions, including using 3% acetic acid and water as food simulants. The researchers detected low concentrations (sub–ppb levels) of silver in the migration studies. Silver NPs were not detected in food simulants. This finding suggests that the silver migration may be due solely to ionic silver released from FCMs when in contact with acidic and aqueous food simulants. The absence of detectable silver NPs was expected, as it is impractical from a physico-chemical point of view, the authors assert. For the products tested, the current FDA Guidance for evaluating migration from FCMs was applicable, the authors say. Yet, they also point out that silver migration from the FCMs appeared to be predominantly a surface process. Thus, any conditions that will lead to significant changes to the surface properties may, in turn, influence the silver concentration in the simulant. Thus future studies shall evaluate the potential for NP release under conditions that change the exposed surface area of the FCMs.

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Ntim, S.A. et al. (2015). “Characterization and potential migration of silver nanoparticles from commercially available polymeric food contact materials.Food Additives & Contaminants: Part A (published online April 1, 2015).