Migration is the mass transfer process by which low molecular mass constituents initially present in the package are released into the contained product. Since packaging materials are not chemically inert and, direct contact between the package and the product packaged can lead to substance migration into the product. In food packaging, this process is critical since the non-intended transfer of undesirable packaging constituents may affect the food safety for the consumer (Torres, Guarda, Moraga, Romero, &Galotto, 2012). In active packaging, nanomaterials may migrate into food once present in the food packaging materials. The migration of nanomaterials could eventually induce organoleptic changes of foods. For example, TiO2 could cause rancidity resulting from lipid oxidation in lipid foods (de Azeredo, 2013). The potential risk from nanotechnology has to be defined better in terms of the properties of the nanomaterials and their transfer rate. Because of poor packaging performance and subsequent migration of nanomaterials from the packaging, ingestion of foods previously in contact with nano-packaging can be an exposure route (Cushen et al. 2012). For investigating the possibility of applying nanomaterials to the food packaging usage and assessing the safety of a package in contact with foodstuffs, it is necessary to carry out migration analysis under controlled conditions, which depends directly on the foodstuffs or the type of food simulant tested.
This section reviews critically the current state of experimental and theoretical investigations of migration from food packaging containing nanomaterial. Table 2 provides a summary of currently available migration studies for food packaging nanomaterials, including study conditions and key observations.