Theoretical studies of polymer packaging can prolong safe storage times of food

Food packages are able to protect food from the environment. Passive packages that control moisture or oxygen transfer are already known. Active packages, playing an active role in maintaining or even improving the quality of the enclosed food, by delivering selected chemical or antimicrobial agents, have recently been put on the market. Thus, some fundamental studies are necessary in order to improve their development in various ways. Some parameters of interest are considered here in mono- and multi-layer polymer systems:- the quality of the contact between the polymer and the liquid food, together with the coefficient of convection, the concentration of the agent in each layer, and the thickness of each layer in multi-layer systems. The process of agent transfer is controlled by diffusion through the multi-layer package and by convection into the liquid food with a finite coefficient of convective transfer. A numerical model is built, as no analytical solution exists for this problem. The results are expressed in terms of profiles of concentration of the agent developed through the package, and in terms of the kinetics of transfer into the liquid food.