Rotten meat doesn't stand a chance

Apr 01, 2011
The sensor film changes color, from yellow to blue. Proof positive that this fish is spoiled. Credit: Fraunhofer EMFT

When it comes to packaged fish or meat, it is nearly impossible to distinguish between fresh goods and their inedible counterparts. Researchers have now developed a sensor film that can be integrated into the package itself, where it takes over the role of quality control. And if the food has spoiled, it changes color to announce the fact.

Is the vacuum-packed chicken leg really still fresh and edible? Looks alone do not tell the whole story. And the “best-before” date is no guarantee, either. Scandals involving the sale of rotten meat have added to the uncertainty, and the customer him- or herself may be shortening the shelf life through improper storage. This is an area in which a sensor film developed by the Fraunhofer Research Institution for Modular Solid State Technologies EMFT in Munich can immediately give a green – or rather: yellow light, or warn of spoiled goods. EMFT developed the film in a project sponsored by the German Federal Ministry of Education and Research.

The sensor film is integrated into the inside of the packaging, where it responds to biogenic amines. Amines are molecules produced when foods – and meat foremost among them – decay. They are also responsible for their unpleasant smell. If amines are released into the air within the packaging, the indicator dye on the sensor film reacts with them and changes its color from yellow to blue. “Once a certain concentration range is reached, the color change is clearly visible and assumes the task of warning the consumer,” explains Dr. Anna Hezinger, a scientist at EMFT. This is not only interesting when it comes to identifying foods that have become inedible. Many people are also extremely sensitive to the presence of certain amines. Which makes a warning all the more important for them. 

“Unlike the expiration date, the information on the sensor film is not based on an estimate but on an actual control of the food itself,” Hezinger emphasizes. At the same time, the system is very inexpensive. This is important if it is to be used on a broad scale. Other solutions – such as electronic , for instance – would lead to a steep increase in the price of packaged meat. Things that come in direct contact with food products must also meet high standards. “Food safety is ensured by a barrier layer between the sensor film and the product itself. This barrier is only permeable to gaseous amines. The indicator chemicals cannot pass through,” Hezinger explains.

Scientists are also working on a measurement module with a built-in sensor film. Employees in the food and packaging industries can use the module to test the freshness of food products directly. The device objectively analyses the color response while at the same time providing a more precise result than is possible with the human eye. This also permits an exact identification of intermediate shades of color. Dr. Anna Hezinger and her team are currently looking for partners in industry with which to further develop and produce the sensor film and measurement module.

Explore further: Stanford aims to bring player pianos back to life

add to favorites email to friend print save as pdf

Related Stories

Active packaging keeps meat fresh for longer

Oct 01, 2010

To date, supermarkets have only been able to keep products on their meat counters for a few days. But now researchers have developed an antimicrobial active packaging film that destroys the microorganisms ...

Infections detected by new dressing

Nov 02, 2010

Wounds have to be regularly checked, to make sure any complications in the healing process are detected at an early stage. A new material will make it possible to check wounds without changing the dressing: ...

Crash sensor boosts safety in warehouses

Apr 01, 2011

For reasons of workplace safety, storage shelves in warehouses are subjected to routine testing of their stability. These inspection rounds are time-consuming and deliver just a snapshot in time. Researchers ...

UV-transparent coating for image sensors

Feb 08, 2011

Image sensors as used in cell phones are partially color-blind. This is because of their coating, which prevents UV light from passing through. CMOS chips have as a result not been suitable for spectroscopy ...

Recommended for you

EDAG car with textile skin set for Geneva show

14 hours ago

Making its debut at the Geneva Motor Show 2015 is the EDAG Light Cocoon. This is promoted as a new dimension for lightweight construction, a sportscar with a textile outer skin panel. The EDAG Light Cocoon ...

Stanford aims to bring player pianos back to life

Dec 17, 2014

(AP)—Stanford University wants to unlock the secrets of the player piano, which brought recorded music into living rooms long before there were cassettes, compact discs or iPods.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

ereneon
5 / 5 (1) Apr 01, 2011
If there are scandals of selling rotten meat, then is it really that hard to include a fake spoilage detector?...

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.