default alt-text

Packaging under protective atmosphere

Manufacturers of sensitive or perishable products want to ensure premium product quality over long periods of time. Modified atmosphere packaging preserves the freshness and quality of products, lengthening shelf life for food producers.

MAP Modified Atmosphere Gas Packaging

For this reason, packaging under protective gas has become well-established, especially in the food and delicatessen industry. For quality assurance apply strict hygiene and highest demands to the technical equipment. That’ s why our high-end gas analysers are used to monitor modified atmosphere packaging.

Packaging under protective gas - the way it works

The principle: In simple terms, the natural ambient air in the packaging is replaced by a modified gas mixture. Nitrogen (N2), carbon dioxide (CO2) and oxygen (O2) are used in different concentrations, depending on the intended use.

Which inert gases are used?

Gas mixtures MAP Modified Atmosphere

Typical protective gases are nitrogen (N2), carbon dioxide (CO2) and also oxygen (O2). These inert gases exist as components in naturally air. In modified atmosphere packaging, however, these gases are used in a mixture (relative composition) that is different from the air. These modified gas mixtures are under constant control, either on the packaging line or in the laboratory or in the trade.

Inert gases at a glance


Nitrogen (N2) is present in approximately 78 % of air. It is an inert gas and does not react directly with the food. As a packaging gas, it is used in peculiar to suppress oxygen (O2) out of air. This indirectly prevents the oxidation of food and inhibits the growth of oxygen-dependent (aerobic) microorganisms.


Carbon dioxide (CO2) is an important protective gas. It changes the pH value of the product environment and reduces the formation of mould or the growth of bacteria, because it influences the permeability of the cell membrane. The concentration must be chosen carefully, because when it is dosed too high, CO2 has a taste-altering effect. Furthermore, due to its high fat or water solubility and high permeation capacity, it can easily cause packaging to lose pressure.


Oxygen (O2) is present in natural air at a concentration of about 21% and is a condition for the growth of aerobic microorganisms. O2 favours oxidation-induced spoilage. Therefore, in modified atmosphere packaging, oxygen is normally significantly reduced or even eliminated. For fresh red meat, on the other hand, the oxygen content will be increased to maintain or intensify the red colour.

Check inert gas packaging with gas analysers

Control procedure MAT with gas analyser

In quality assurance, testing is very simple: the puncture point of the packaging is provided with a septum. The tester pricks the packaging with the needle. The measurement is started by pressing the button and the gas mixture is sucked out of the packaging into the measuring device. The result is displayed in 5 – 15 s (depending on sensor equipment & application). Gas analysers work with modern sensor technology. They are precise and require only a very small amount of gas (approx. 3 – 7 ml). Collected measurement data is stored and can be archived for permanent, complete documentation of quality control.

Overview of practical solutions

Spices-Food Modified Atmosphere Gas Analysis MAT

In the case of snacks, nuts, spices or coffee, the greatest risk of deterioration is their high content of fat. Oxidation has the effect that fats go rancid. To inhibit this, in the packaging oxygen is significantly reduced and replaced by a pure nitrogen atmosphere (N2). For testing such special protective atmospheres, the very economical MAT1100 gas analyser is suitable. The integrated EC sensor enables measurement in a range of 0.5 – 35 vol.% O2– concentration. Ideal if only the oxygen concentration is of interest or if only nitrogen is used for gassing.

Vegetable foods need oxygen for cellular respiration

Application Food Modified Atmosphere Gas MAP

Fresh fruit or vegetables (especially in prepared, cut form) have special requirements for packaging in a modified atmosphere. Different to other groceries, fresh fruit and vegetables continue to exhale after picking. In addition, the packaging film must not be completely tight. The composition of the inert gas should equally reduce spoilage in the form of oxidation or microbiological change and maintain cellular respiration. This is termed an Equilibrium Modified Atmosphere (EMA). The MAT1200 gas analyser is ideal for measuring Oand CO2 concentrations.

Protective gas packaging ensures quality for sensitive products

Baby food Packaging Modified Atmosphere Gas

To extend the shelf life of milk powder, especially the highly sensitive product of baby food, attention is given to displacing oxygen from the packaging. In praxis, baby milk powder is often packed under pure nitrogen, with as little residual oxygen as possible. For testing, the quality assurance works with a MAT 1400 gas analyser. It has a measuring cell for very low sample gas requirements, with high accuracy for very low Oconcentration ranges. Its zirconia measuring cells measure the Oconcentration in the measuring range of 0 – 100 vol.%. The device is also used for checking sterilised finished products.

Protective gas packaging as an important aspect of sustainability

Especially with fresh food, such as bio-meat, the sustainability aspect comes into play. Under modified atmosphere packaging, this high-quality food products can be stored twice or three times longer without losing their quality. Wastage and food loss are reduced, packaging material is decreased. Here often the MAT1500 gas analyser is used for monitoring. Primary application of using is to check fresh meat packaging (70-80% oxygen and 20-30% carbon dioxide). The instrument has a zirconium dioxide sensor (O2 measurement) and a non-dispersive infrared sensor (CO2 measurement). A measurement with the device takes only about 10 -15 seconds. The sensors can even be used at low temperatures or in the meat industry on packaging lines. In addition, the measuring gas requirement is low, even an excellently measurement of ready-packed sausage, with low headspace, is possible.

Gas analysers invaluable devices in modern packaging processes

Areas of application and use:
Here, gas analysers support the quality control of protective packaging in numerous companies and help to ensure that a high-quality, fresh product arrives at the customer’s site.

  • Random sample measurements on the line during the packaging process
  • Inspection after revision: change in film or packaging materials
  • Modification on the packaging machine: sealing seams, welding seams
  • Retained samples, quality assurance in the laboratory
  • Tests on the shipment

Any Questions?

We will be glad to help.

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

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