Food and Beverages Packaging

Food Contact Material Migration

Chemical partitioning from the packaging into the food is known as migration. Migration is of relevance for smaller size compounds (below 1000 Da). The extent to which migration occurs depends on various factors:

The physico-chemical properties of the migrant, of the packaging material, and the food (e.g. fat content)

·         Temperature

·         Storage time

·         Size of the packaging in proportion to the foodstuff volume (smaller size packaging has a larger surface to volume ratio).

The types of chemicals that can migrate from packaging into food are highly diverse and depend on the type of packaging material. For inert materials (stainless steel, ceramic, glass), only chemicals from the inside surface, directly in contact with the foodstuff, can migrate. They transfer from the inner surface to the food by surface exchange. Chemical diffusion from within the packaging material or from the outside (printing inks, adhesives) is not possible. This inertness is due to the chemical structure, with pore sizes that are small and prevent molecules or single atoms from passing through. However, glass-packaged oily foods can be contaminated by migration of plasticizers (like epoxidised soy bean oil (ESBO) or phthalates) from the closure. Migration can be reduced by careful manufacturing or the use of specially developed low migration closures.

Non-inert materials, like paper and board or plastics, can be a direct source of migrants. Chemicals may also migrate from the outside through the packaging. An example are printing inks that have been shown to migrate through paper board  into dry foods. The large pore size of paper-based materials permits smaller molecules to migrate from the outside to the food inside. The use of barrier materials can reduce food contamination significantly. For example, carton with an inner bag that contains the foodstuff and that is made of aluminium foil or plastics with barrier properties.