Theoretical treatment of pollutant transfer in a finite volume of food from a polymer packaging made of a recycled film and a functional barrier.

The problem of pollutant transfer in food from a polymer packaging made of a recycled film and a functional barrier is studied from a theoretical point of view. In the present case, the process is controlled by Fickian diffusion through the two films of the polymer packaging in perfect contact and by convection into the food. A numerical model is built, taking all the facts into account: the diffusion of the pollutant through the two polymer films, a convective coefficient of mass transfer on the surface, a partition factor, the volume of the liquid and the thicknesses of the polymer films. The results are expressed by using dimensionless numbers so that they can be used for various cases, viz the kinetics of pollutant transferred into the food and the profiles of concentration of the pollutant through the packaging.