The atmosphere inside a MAP pack is replaced by a gas mixture appropriate for the product in order to maintain the shape, colour and freshness of the product. This modified atmosphere usually consists of carbon dioxide, nitrogen and oxygen.
Among the advantages of a MAP pack are the extension of the shelf life and the assurance of quality, as well as handling and transport protection of the product. When packaging food, the shelf life can be extended by the use of MAP without using food additives. Industrial and consumer goods can be protected from corrosion through the use of a modified atmosphere in the pack.