Oxidation of foods is largely chemical process driven by oxygen, which can be blocked by the displacement of oxygen by nitrogen.
The gas packaging technique involves packaging of product in an impermeable film with the appropriate gases and heat sealing of packages.
The gases commonly used for gas packaging of bakery products are N2 and CO2, These are neither toxic or dangerous nor are they regarded as food additives.
Other gases which have antimicrobial properties include carbon monoxide, sulphur dioxide ethylene oxide, ozone, nitrous and nitric oxide.
In inert gas packaging the air inside the container is replaced by inert gas either through the compensated vacuum technique or by flushing the inside of the package with inert gas.
In the former case, first a vacuum is created in the package, then enough inert gas to balance the internal and external pressure is admitted. In the latter case, a drop of liquefied inert gas is placed in the bottom of the package, which evaporates pushing the air out.
MAP gases can be delivered either as pre-mixtures in cylinders or as bulk gases to be mixed on site. Bulk gases may be delivered as compressed gases in cylinders or as cryogenic liquids.
Gas packaging
