Background The development of applications using nanomaterials is accompanied by safety concerns due to gaps in understanding the toxicology. In case of incorporation in food contact polymers, the first step to consumer exposure is the transfer of nanomaterials from the polymer to the food. Thus, in order to evaluate the risk the key questions are whether nanoparticles can be released from food contact polymers and under which conditions. Scope and Approach This article critically reviews the published nanomaterial migration studies which are partly contradictory. The influence of analytical techniques and the experimental design on the results are discussed. Theoretical approaches by mathematical modelling are addressed. Furthermore, a short overview on nanomaterial applications for food contact materials and on the regulatory situation in Europe and USA is given. Key findings and conclusions Distinguishing between particle release and migration of dissolved ions is crucial for proper interpretation of migration results. Nanosilver which is the mostly investigated species, and other metals are easily oxidized to ions but can re-form nanoparticles at slightly reductive conditions, e.g. at sample preparation, pretending particle migration. At cutting edges the particles may be released due to weak binding to the surface. Nanoparticles which are completely encapsulated in the host polymer matrix do not have a potential to migrate into food. Thus, consumers will not be exposed to nanoparticles from food contact polymers when those are completely embedded in polymer and the contact surface is not altered by mechanical surface stress during application

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Carbon black was investigated to assess and quantify the possibility that nanoparticles might migrate out of plastic materials used in the food packaging industry. Two types of carbon black were incorporated in low-density polyethylene (LDPE) and polystyrene (PS) at 2.5% and 5.0% loading (w/w), and then subjected to migration studies. The samples were exposed to different food simulants according to European Union Plastics Regulation 10/2011, simulating long-term storage with aqueous and fatty foodstuffs. Asymmetric flow field-flow fractionation (AF4) coupled to a multi-angle laser light-scattering (MALLS) detector was used to separate, characterise and quantify the potential release of nanoparticles. The AF4 method was successful in differentiating carbon black from other matrix components, such as extracted polymer chains, in the migration solution. At a detection limit of 12 µg kg−1, carbon black did not migrate from the packaging material into food simulants. The experimental findings are in agreement with theoretical considerations based on migration modelling. From both the experimental findings and theoretical considerations, it can be concluded that carbon black does not migrate into food once it is incorporated into a plastics food contact material.

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In this study, the migration potential of laponite, a small synthetic nanoclay, from nanocomposites into foods was investigated. First, a laponite/ethylene vinyl acetate (EVA) masterbatch was compounded several times and then extruded into thin low-density polyethylene (LDPE) based films. This way, intercalation and partial exfoliation of the smallest type of clay was achieved. Migration of laponite was investigated using Asymmetric Flow Field-Flow Fractionation (AF4) with Multi-Angle Laser Light Scattering (MALLS) detection. A surfactant solution in which laponite dispersion remained stable during migration test conditions was used as alternative food simulant. Sample films with different loadings of laponite were stored for 10 days at 60 °C. No migration of laponite was found at a limit of detection of 22 µg laponite per Kg food. It can be concluded that laponite (representing the worst case for any larger structured type of clay) does not migrate into food once it is incorporated into a polymer matrix.