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Fraunhofer develops x-ray alternative for food inspection

By Oliver Nieburg , 01-Dec-2011

Fraunhofer develops x-ray alternative for food inspection

Researchers have developed technology using millimeter waves that could allow food manufacturers to examine finished products through packaging and give advantages over x-ray detection, the current preferred method.

The Fraunhofer Institute’s recently developed Stand Alone MilliMeter wave Imager (SAMMI) uses wave sensors to see through all non-transparent materials. The technology can test whether food products, such as chocolate, have been properly filled and pick up on any impurities.

It can also assess whether plastic seams on items have been packaged correctly and detect harmful contaminants.

Advantages over x-ray detection

Dr Helmut Essen at Fraunhofer told that the industry standard for scanning finished products was x-ray which he said was expensive and sent out harmful ionizing radiation.

“X-Ray is dangerous. You must take care to operate it and they are not suited for soft fillings,” he said.

The machine contains a transmitting and a receiving antenna on two opposing rotating plates.

A conveyor belt transports an item between the antennae, while these send electromagnetic waves in a high frequency of 78 GHz. Different areas of the item absorb the signal to different degrees, leading any differences in composition to show up in images.

Basically we examine the scanned objects for dissimilarities,” said Essen.

Potential for technology

Fraunhofer’s current device is no larger than a compact laser printer, but is not yet ready for industrial scale inspection.

At present it can only see real time images and inspects small items no higher than 2cm. It also takes around two minutes to inspect a single item, but Fraunhofer are hoping develop faster machines for industrial use.

Esssen said the development would take place in the next year and a half and he hoped a larger machine would be ready within a year that could can at up to six metres per second.

The company has a small contract with Proctor and Gamble to detect contaminants in nappies, but despite exhibiting at a number of trade shows has had little interest from food manufacturers who are perhaps waiting for an industrial scale machine.

Fraunhofer has done demonstrations for Lindt and tested Milka Hearts (made by Kraft) to ensure every heart had a filling.

Esssen said the technology could be used to test for cake fillings to see if jam is present.

Manufacturers could also test products after they have been stored for long periods, he said.

Fraunhofer has also tested the technology to assess freshness in avocados and used it to examine how veins in salad were transporting water.


Essen said SAMMI machines would not be expensive for food companies as the parts used were “readily available components from the automotive industry”.

For the small machine that has already been developed, Essen expects the cost to be between €30,000 and €40,000.

When an industrial machine has been developed, he said food companies could expect to pay around €50,000.

He said an x-ray machine would be almost three times more expensive on an industrial scale and companies must also take additional precautions that are not necessary with SAMMI machines.

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