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Packaging under protective atmosphere

An overview of Modified Atmosphere Packaging (MAP)

In order to be successful on the market, manufacturers of sensitive or perishable products must be able to guarantee first-class quality over a long period of time. This applies, in particular, to the food industry but also the electronics, pharmaceutical or cosmetics industry. Modified Atmosphere Packaging (MAP) plays a decisive role in this. Typical protective gases are nitrogen (N2), carbon dioxide (CO2) and oxygen (O2) as well as a mixture of these gases. These are natural components of the ambient air but in modified concentrations that need to be checked. In most food packages, the oxygen concentration is reduced while the carbon dioxide concentration is increased in order to inhibit the  growth of aerobic microorganisms. That also allows you to slow down oxidation processes that change the ingredients and thus the taste and colour of the products. Other  foodstuff, however, requires a certain oxygen content inside the packaging so it can stay fresh or keep its colour. But protective gases are not only used in the food industry. Electronic components are also packaged under nitrogen in order to prevent oxidation and corrosion processes. The same applies to pharmaceutical or cosmetic products, for example, in vials or blister packages. In addition, the modified atmosphere stabilises the packaging providing the product with a mechanical protection.

Analysis of headspace volume

MAT1000 series Sampling from meat packaging

In order to check the mixture ratio of the protective gases inside a package, a self-adhesive septum is applied to a sampling point. The suction needle of the gas analyser
is then inserted through the septum into the headspace of the package. A simple touch on the touch-screen of the device will ensure that the required sample is automatically drawn in. Within a very short time, the oxygen and carbon dioxide content is measured, the nitrogen content calculated, and the results are shown on the display.

Protective gases


Nitrogen (N2) is an inert gas and does not react with surrounding substances. For manufacturing reasons, it has a high purity of up to 99.99 %, it is colourless, odourless and tasteless and diffuses only very slowly through plastic film. That is why it is used in MAP to displace oxygen, to adjust a gas mixture or to function as a filling gas that prevents the collapse of the  packaging. A 100 % nitrogen atmosphere is used for snack products to prevent oxidation and thus rancidity

Carbon Dioxide

Carbon dioxide (CO2) – colourless, odourless and tasteless just like nitrogen – inhibits oxidation processes and the growth of most aerobic bacteria and moulds. It is therefore often used to increase the storage life of packaged foodstuff. Generally, the following applies: the higher the CO² content, the longer the storage life. However, some food will
change its taste if the CO² content is high. In addition, the gas might be absorbed by the product or escape from the packaging making it collapse.


If food comes into contact with oxygen (O2), it will usually oxidise and go bad. Oxygen also allows for the growth of aerobic microorganisms. This is the reason why protective gas packaging often does not contain any oxygen or only very little. Fresh produce, however, requires oxygen since it still “breathes” after the harvest. A high O² content of 70 % in the packaging is even beneficial in
case of raw red meat: It prevents the product from becoming “pale” as well as its colonisation by anaerobic microorganisms.

Any Questions?

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A.KRÜSS Optronic GmbH
Alsterdorfer Str. 276-278
22297 Hamburg | Germany

Tel. +49 40 5143 17-0
Fax +49 40 5143 17-60