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."
The sensor film is placed behind a barrier layer that is only permeable for gaseous amines, so there are no food-contact concerns around the sensor. The EMFT says the system is also less expensive than some other solutions, including electronic sensors.
Scientists are also developing a measurement module with a built-in sensor film, whereby food and packaging employees can directly test the freshness of food products. That device analyzes color response for results that are more precise than is possible with the human eye. Hezinger and her team are currently looking for industry partners to further develop and produce the sensor film and measurement module.
