Modified Atmosphere Packaging (MAP) for Fresh Fruits and Vegetables

Controlled atmosphere (CA) storage and modified atmosphere packaging (MAP) are two useful technologies to extend the shelf-life of fresh agricultural and horticultural produce.

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Simply stated, these technologies involve storing a fruit or vegetable in a modified atmosphere usually consisting of reduced O2 and elevated CO2 concentrations compared to air. The modified atmosphere reduces the rates of respiration and ethylene production, which are often associated with the benefits of retardation of physiological, pathological, and physical deteriorative processes occurring in the product.

Unlike most food products, fresh fruits and vegetables continue to ‘breathe’ or respire after they have been harvested. This process consumes oxygen and produces carbon dioxide and water vapour. The key to keeping these packaged products fresh for as long as possible is to reduce the respiration rate without harming the quality of the product – its taste, texture and appearance. In general, the rate of respiration can be reduced by keeping the temperature low, having lower levels of oxygen in the packaging atmosphere and increased levels of carbon dioxide. However, things are not straightforward. For example if there is too little oxygen in the packaging atmosphere, a process called anaerobic respiration will kick in. This produces unwanted tastes and odours in the product and will cause the food to deteriorate. Furthermore, excessively high carbon dioxide can damage some varieties of product.