The RoadMAP to Packaging Performance

Modified-atmosphere packaging (MAP) refers to the addition or removal of gases to achieve an atmospheric composition in the package that extends the shelf life of the food and retards—or, even better, prevents—undesirable changes to the safety, sensory characteristics and nutritive value of the food, explains John Floros, professor and head of the Department of Food Science, Pennsylvania State University, State College. “MAP achieves this through three principles,” he says. “First, it reduces undesirable physiological, chemical, biochemical and physical changes in the food. Second, it controls microbial growth. And finally, just like any other packaging technique, it prevents product contamination.”

The three main gases used in MAP are nitrogen, oxygen and carbon dioxide. Nitrogen is considered inert and has no antimicrobial activity. Carbon dioxide, on the other hand, provides a bacteriostatic effect. Oxygen inhibits growth of anaerobic microorganisms, but does allow for growth of aerobic microbes. Thus, with heat-and-eat meats, MAP technology, coupled with vacuum, eliminates all of the oxygen in the package, replacing it with nitrogen and carbon dioxide.

“The technology is application-specific and depends on the food, the packaging material, the gas delivery system and even storage and distribution conditions,” says Floros. “Regardless, MAP is critical to the success of many foods, including heat-and-eat meats. MAP offers many advantages, from better final-product quality and longer shelf life to eliminating the need for chemical preservatives.”

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