Presentation and Experimental Verification of a Physico-Mathematical Model Describing the Migration across Functional Barrier Layers into Foodstuffs

The starting point of this work was the fact that functional barriers are in most cases already in-situ-contaminated due to the thermally extreme coextrusion conditions of the manufacturing process. As a consequence, middle layer contaminants may already have penetrated the functional barrier of a food package and may provide direct contact with the foodstuff at the time when the package is filled. Nevertheless, depending on the individual food package parameters, the remaining functional barrier efficiency can still prevent inadmissible migration. To meet this real-life situation and to describe the underlying migration process a theoretical migration model was developed and experimentally verified in this work using artificially contaminated multilayer HIPS sheets with different functional barrier thickness. An important result of this study was the finding that compared with the interdiffusion between the package's layers in situ during their formation in the coextrusion process, th e interdiffusion at ambient temperature until the filling time point of the package is able to be neglected.