+1 (630) 645-0600 [email protected]

Modified Atmosphere Tester

Kruess MAT1000 series gas analyzers feature a user friendly interface with a state-of-
the-art touch-screen display that ensures a clear, bright, visual representation of all
information. The integrated touch-screen allows even non-expert personnel to intuitively and quickly operate the device. Once the measurement is started, sample is drawn in, and the display shows the measured values for oxygen, carbon dioxide, and nitrogen as well as, air pressure, and gas flow – depending on the model – temperature of the measuring cell.

Only a small sample volume is required, and stable measurement values are
available in five to ten seconds. Optionally, measurements can be triggered with a foot switch allowing for a fast, fatigue-proof mode of operation when serial analyses are performed.


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 analyzer
is then inserted through the septum, into the headspace of the package. A simple touch on
the screen of the device ensures that the required sample is automatically drawn. In less
than 10 seconds, the oxygen and carbon dioxide content is measured, and nitrogen
content is calculated. Results are shown on the instrument display.


Nitrogen 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 colorless, odorless and tasteless and diffuses only very slowly through plastic film.

That is why it is used in Modified Atmosphere Packaging (MAP) to displace oxygen, adjust a gas mixture or 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 is colorless, odorless and tasteless just like nitrogen. It inhibits oxidation processes and the growth of most aerobic bacteria and molds. It is therefore often used to increase the storage life of packaged foods. 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, it will usually oxidize and go bad (rancid). 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 be coming “pale”, as well as, its colonization by anaerobic micro- organisms.



In order to meet the different requirements of protective gas packaging quality control, Kruess offers types of gas analyzers.


Electrochemical oxygen cell (EC)

The measurement range of the electrochemical oxygen cell between 0.5 and 35 volume per cent O 2  makes it especially interesting for products such as fresh fruit, raw, low-fat fish or sea food, which are packaged neither under an oxygen-free nor particularly
oxygen-rich modified atmosphere. Since this low-cost measuring cell is quickly ready for use, it is recommended for sporadic sample checks or if only a few samples are measured every day.

The low-drift long-life cell in our MAT1100 and MAT1200 devices boasts an above- average service life of up to six years. Unlike conventional alkaline cells, it uses an acidic electrolyte (formic acid), which is why its cross-sensitivity toward acidic gas components such as carbon dioxide is low (< 0,002 vol.-% O 2  with a load of 100 vol.-% CO 2 ), and a measured value correction as a function of the CO 2  concentration is not required. Carbon monoxide from coffee packaging or flammable gas components such as alcohol do not influence on the specified accuracy.