Migration by 'direct' or 'indirect' food contact? 'Dry' and 'wetting' foods? Experimental data for 'touching' contact of dry foods with paper and board

Food contact is characterised in various terms, all of which are somewhat ill-defined. This work investigated the simplification that migration from food contact materials into dry food virtually exclusively proceeds through the gas phase, which would imply that the migration of essentially non-volatile components is negligible. It is shown here that this is not necessarily appropriate: for newspaper printed with an ink based on essentially non-volatile polyalphaolefins (PAO) as the main solvent, the migration into polenta and a baking mix reached 64% and 66% respectively of the content in the paper in merely 20days at ambient temperature. Migration of involatile substances into dry foods implies diffusion through the paper to the small contact points. It depended on particle size, as this determines the density of the contacts. The diffusion rates within the food contact material and the food, including the transfer from one particle to the next, are other determining factors. This leaves the question whether such migration can be modelled or tested in a systematic manner (simulation), or whether it needs to be determined on a case-by-case basis.