Catch of the day? This color-shifting film can’t lie

04/04/2011

A new sensor film integrated into multilayer fresh meat and fish packaging responds to biogenic amines, an indicator of spoilage, by changing colors and letting retailers and consumers know when meat's no longer fit to eat. The plastic film, which was developed by Fraunhofer Research Institution for Modular Solid State Technologies (EMFT; Münich), shifts its tint to warn of spoiled goods. EMFT developed the film in a project sponsored by the German Federal Ministry of Education and Research. The EMFT notes that unlike an expiration date, the sensor film's reading is not based on an estimate but on an actual control of the food itself.

Amines are molecules produced when fresh foods, particularly fish and meat, start to decay, bringing with them a pungent odor. If amines are released into the air within the packaging, the indicator dye on the sensor film reacts with them and changes color from yellow to blue. Once a certain concentration range is reached, the color change is clearly visible and warns consumers, according to EMFT scientist Anna Hezinger. "This is not only interesting when it comes to identifying foods that have become inedible," Hezinger said in a release. "Many people are also extremely sensitive to the presence of certain amines, which makes a warning all the more important for them."...
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