Food Packaging Sensor Detects Spoiled Food

An innovative thin film layer sensor that can be integrated into food packaging changes color when it comes into contact with spoiled food.

Researchers from the Fraunhofer Research Institution for Modular Solid State Technologies (Munich, Germany) developed the novel sensor, which responds to biogenic amines, molecules that are produced when foods--especially fish and meat products--decay. If these amines are released from the spoiled food into the air within the packaging, the indicator dye on the sensor film layer reacts with them, changing its color from yellow to blue. Food safety is ensured by a barrier layer between the sensor film and the product itself, which is permeable only to the gaseous amines themselves; the indicator chemicals cannot pass through.

Another important feature of the product is that it is very inexpensive. This important in bulk manufacture, since other solutions, such as electronic sensors, would lead to a steep increase in the price of packaged meat and other products. The researchers are also working to develop a complementary measurement module with a built-in sensor film, which would allow employees in the food and packaging industries to test the freshness of food products directly.

"Once a certain concentration range is reached, the color change is clearly visible and assumes the task of warning the consumer,” explained lead researcher Anna Hezinger, PhD. "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.”

Some prominent examples of biogenic amines include histamine, an important stimulant of hydrochloride (HCl) secretion by the stomach. Histamine is derived from the amino acid histidine that acts as a neurotransmitter mediating arousal and attention, as well as a pro-inflammatory signal released from mast cells in response to allergic reactions or tissue damage. Other biogenic amines include Tyramine, a substance found in many common foods, associated with increased blood pressure and headaches; serotonin, a central nervous system (CNS) neurotransmitter involved in regulating mood, sleep, appetite, and sexuality; and several catecholamine neurotransmitters in the CNS.

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Fraunhofer Research Institution for Modular Solid State Technologies