What Each Gas Does

What Does Each MAP Gas Do?

Nitrogen (N₂) – an inert gas with two principal MAP functions.
1. As a replacement for air, and primarily to exclude oxygen.
2. As a filler gas – nitrogen is not soluble. Carbon dioxide for example is both water & fat soluble and it’s use can cause packs to deflate.

Carbon Dioxide (CO₂) – has the primary MAP function of inhibiting the growth of aerobic bacteria. However, because of the solubility of carbon dioxide in water & fat, packs collapse from a reduction in internal pressure as the gas dissolves, and a slight tainting of the product may result.

Oxygen (O₂) – usually, oxygen is excluded in MAP packaging, because it causes oxidative deterioration of foods. However, it maybe used as an MAP gas to:
1. Inhibit anaerobic organism growth
2. Allow respiration to occur (important for fruit & vegetables)
3. Maintain colour (particularly in red meats)

Which Gas Mix Should Be Used?

Expert advice should be obtained to ensure that the most appropriate gas mix is used for packing each specific product. We recommend speaking to the MAP specialist at a gas supply company, or at the Food Research Company. Those offering advice include: