A comprehensive study into the migration potential of nano silver particles from food contact polyolefins

The potential of nano silver particles (Ag-NPs) to migrate from food contact polyolefins into food was systematically investigated. Migration studies were carried out using low density polyethylene (LDPE) films with different concentrations of incorporated Ag-NPs in contact with different EU-official food simulants simulating long-term storage with aqueous and fatty food contact. Detectable migration of total silver as measured by inductively coupled plasma mass spectrometry (ICP-MS) was found in aqueous food simulants only. Stability tests of Ag-NPs in these food simulants by asymmetric flow field-flow fractionation (AF4) analysis showed rapid oxidative dissolution of the Ag-NPs and demonstrated that only ionic silver was present in the migration solution. Non-detectability of silver both in the isooctane and 95 % ethanol migrates indicated that Ag-NPs would not be able to migrate. These findings were supported by a new approach of migration modeling showing that nanomaterials (NMs) in general are immobilized in a polymeric matrix, resulting in a very limited hypothetical potential for the migration of NMs smaller than 3-4 nanometer in diameter. However, such small nanoparticles are usually not found in polymer nanocomposites. The results of this study suggest that migration of nanoparticles from food contact plastics cannot lead to an exposure of the consumer