Films for MAP of foods

To understand the role of a packaging film in the design of a modified atmosphere pack, it is important to consider the inherent potential variability of a modified atmosphere system. The term ‘controlled atmosphere packaging’ is now replaced with the more accurate description of ‘modified atmosphere packaging’ (MAP) because an exact atmosphere might be achieved initially, but immediately changes start to take place, including variation due to the packaged product, for example respiration of a packaged leaf content. Most significantly the contained atmosphere and the external ambient atmosphere tend to equilibrium, the degree dependent upon the differential pressure. It is in this context that the barriers provided by the container must be considered.