New freshness sensors can help reduce food waste

Researchers at Imperial College London are reporting that food freshness sensors may eventually replace use-by dates to reduce the amount of food that is wasted by supermarkets and consumers. The new food sensors can help detect spoilage gases like ammonia that are present in meat and fish products.

Around 33 percent of UK consumers dispose of food based entirely on the use-by date. However, an estimated 4.2 million tons of food that is thrown away each year is actually safe to eat.

The prototype sensors, known as paper-based electrical gas sensors (PEGS), cost only two cents to make. The sensor data can be read by smartphones, making it simple for consumers to scan products and check to see if the food is still edible.

The researchers made the sensors by printing carbon electrodes onto cellulose paper. The materials are eco-friendly, non-toxic, and safe to use in food packaging. A series of microchips, or near field communication (NFC) tags, are incorporated into the sensors so the information can be picked up by nearby mobile devices.

During lab tests on packaged fish and chicken, PEGS picked up trace amounts of spoilage gases quickly and more accurately than existing sensors. According to the researchers, the sensors could eventually replace the use-by date and lower the cost of food for both retailers and consumers.

“Although they’re designed to keep us safe, use-by dates can lead to edible food being thrown away. In fact, use-by dates are not completely reliable in terms of safety as people often get sick from foodborne diseases due to poor storage, even when an item is within its use-by,” explained study lead author Dr. Firat Güder.

“Citizens want to be confident that their food is safe to eat, and to avoid throwing food away unnecessarily because they aren’t able to judge its safety. These sensors are cheap enough that we hope supermarkets could use them within three years.”

“Our vision is to use PEGS in food packaging to reduce unnecessary food waste and the resulting plastic pollution.”

The study is published in the journal ACS Sensors.

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By Chrissy Sexton, Earth.com Staff Writer

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