Witt gas analyser measures trace oxygen levels

By Joseph James Whitworth

- Last updated on GMT

Witt's gas analyser PA 7.0
Witt's gas analyser PA 7.0

Related tags Nitrogen Oxygen Carbon dioxide

Witt has unveiled a gas analyser that can measure trace oxygen levels in the ppm (parts per million) range.

The gas analyser PA 7.0 could be used if the food producer uses a nitrogen generator to produce their own gas.

Witt said these generators are not 100% reliable and to avoid oxygen in the nitrogen they can be combined with a PA ppm gas analyser for permanent monitoring. So the user can do quality control at an early stage of the process.

Undesired oxidation

Alexander Kampschulte, head of marketing, said there are no legal limits regarding oxygen content.

“It’s just about how much does oxygen influence the shelf-life and colour of the product, e.g. when packing fresh meat. For sample testing you just see the result on the display,” ​he told FoodQualityNews.

“For permanent monitoring exceeding of set limits trigger an alarm and switch a potential free contact, e.g. to shut down machinery to avoid quality problems. The limits can be set by the user and are very individual depending on the food product.

“If the food is packed under modified atmosphere in most of the cases the oxygen is replaced by a gas mixture from nitrogen and carbon dioxide. This is to expand the shelf-life of the food. If the packaging process is not correct and the oxygen level is still too high this will cause too early spoilage of the food products.

“Incorrect modified atmosphere packages can have serious effects on the product: from nutrient loss and loss of flavour, taste, texture or colour to spoilage by pathogenic microorganisms.”

The device is available for oxygen, carbon dioxide or oxygen and carbon dioxide.

Zirconium version

All measured values are stored and can be downloaded via a standard interface for further processing. Weighing less than six kilos the PA is 186 x 285 x 270mm in size.

While the classic PA with chemical sensor measures in increments of 0.1%, the new zirconium version detects in the ppm range. Accuracy of the measurements is +/- 5% relative to the measured value.

Witt said zirconium measuring cells offer a quick response and relatively long durability. The sensitive measuring principle allows results in ppm.

They are often used in analysers for monitoring of flow packing machines.

Applications for the standard gas analyser include measurement of oxygen levels for modified atmosphere packaging (MAP).

For this the device has a needle and takes a sample from within the package to check the oxygen level and a ppm version is not required.

It could be used for continuous analysis (inline) directly during the packaging process, said Kampschulte.

“So it can be integrated in the modified atmosphere packing machine for analysis of the right gas mixture. In this case the analyser permanently monitors the gas mixture coming from a gas mixer when adding it into the food pack. This is very often used in flow pack machines,” ​he said.

“[Also], for sample testing via a needle after the packaging process. The PA takes a gas sample to check the oxygen level inside the food pack.”

Kampschulte added the bestselling gas analyser is the handheld device OXYBABY for sample testing.

The PA 7.0 does not replace an old analyser but provides another option for users.

Related topics Food safety & quality

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