Modified atmosphere packaging (MAP) is a preservation technique that replaces the air inside a sealed pack with a controlled gas mixture to slow oxidation, microbial growth and enzymatic activity, extending the shelf life of chilled, fresh or minimally processed food products.
In trade practice
Gas mixtures are product-specific: high carbon dioxide levels inhibit microbial growth in chilled produce, while nitrogen is used to displace oxygen in dry products such as nuts and dried fruit to prevent rancidity. Packaging films must have appropriate gas barrier properties to maintain the modified atmosphere throughout shelf life; film specification and seal integrity are validated at line setup. For frozen fruit and vegetables, MAP is rarely applied because freezing itself controls deterioration. Buyers of chilled or ambient products may specify target gas ratios and require validation data from the supplier.
In a specification
Where MAP is required, specifications state the target gas composition, acceptable tolerance range and the minimum barrier properties of the packaging film, along with shelf-life validation evidence.