What is Modified Atmosphere Processing?

The shelf-life of packaged foods foods is limited by two principal factors: the effect of atmospheric oxygen, and the growth of micro-organisms over time. These factors can bring about changes in odor, flavor and color that effect attractiveness, or can even lead to changes that can make the food dangerous for human consumption.

In order to maximize shelf life, the modified atmosphere packing (MAP) concept for packaged food was created. It consists of modifying the atmosphere surrounding a food product by vacuum or gas flushing of the package, thus controlling the biochemical, enzymatic and microbial actions so as to maximize the freshness of the food without using temperature or chemical treatments like boiling, freezing, irradiation or dehydration.

At its simplest, MAP is the replacement of air in a package with a controlled single gas or mixture of gases. The normal composition of air is 21% oxygen, 78% nitrogen and less than 0.1% carbon dioxide. Typical modification of the atmosphere within the package is by reducing the oxygen content while increasing the levels of carbon dioxide and/or nitrogen. This has been shown to significantly extend the shelf-life of perishable foods at chill temperatures.

List of foodstuffs and their suggested MAP headgas levels.

During food packaging, the package (bag, bottle, carton, etc.) has any remaining air space in the package replaced using a jet of modified air of a known concentration. At the moment the normal oxygenated air is purged, the package is sealed. In a high-speed production environment, this fill, purge and seal cycle can happen hundreds of times per minute.

To test the effectiveness of the modified atmosphere, manufactures will either continuously test the oxygen content in real time during package sealing, will select every X package off the production line for statistical analysis, or both.

For continuous testing, we offer products like the iSense 30-100% CO2 + 25-95% Oxygen Monitor Logger - NEMA4. For spot testing, we make the iSense CO2 and Oxygen Inspection station. For ultra-high speed applications, we have designed ring-arrays for OEM manufacturers.

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