Packets of dry snack foods, such as this packet of Wotsits, commonly use nitrogen as a packaging gas to keep the contents from going stale or damp prior to being opened.
A packaging gas is used to pack sensitive materials such as food into a modified atmosphere environment. The gas used is usually inert, or of a nature that protects the integrity of the packaged goods, inhibiting unwanted chemical reactions such as food spoilage or oxidation. Some may also serve as a propellant for aerosol sprays like cans of whipped cream. For packaging food, the use of various gases is approved by regulatory organisations.[1]
Their E numbers are included in the following lists in parentheses.[2]
Inert and Nonreactive gases
These gas types do not cause a chemical change to the substance that they protect.
These must be used with caution as they may have adverse effects when exposed to certain chemicals. They will cause oxidisation or contamination to certain types of materials.
oxygen (E948), used e.g. for packaging of vegetables
Hydrocarbon gases approved for use with food need to be used with extreme caution as they are highly combustible, when combined with oxygen they burn very rapidly and may cause explosions in confined spaces. Special precautions must be taken when transporting these gases.[4]
