Engineering Minute

Engineering Minute – Low-Cost Sensor Detects Food Spoilage

A team of researchers at Imperial College London have developed a low-cost sensor that could detect spoiled food and reduce food waste. The sensors are known as "paper-based electrical gas sensors" (PEGS) and cost as little as two cents to make. They detect gases given off by spoiled food, such as ammonia and trimethylamine and when paired with a smartphone, can let a consumer know if the food is safe to eat or not. 


“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. 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," says Dr. Firat Güder, team lead at the Imperial College London's Department of Bioengineering. “Our vision is to use PEGS in food packaging to reduce unnecessary food waste and the resulting plastic pollution.”


PEGS are made of carbon electrodes printed onto readily available cellulose paper.


From the Imperial College London article: "Dr Firat Güder's team at Imperial’s Department of Bioengineering, made the sensors by printing carbon electrodes onto readily available cellulose paper.

The materials are biodegradable and nontoxic, so they don’t harm the environment and are safe to use in food packaging. The sensors are combined with ‘near field communication (NFC)’ tags – a series of microchips that can be read by nearby mobile devices.

During laboratory testing on packaged fish and chicken, PEGS picked up trace amounts of spoilage gases quickly and more accurately than existing sensors, at a fraction of their price.

The researchers say the sensors could also eventually replace the ‘use-by’ date – a less reliable indicator of freshness and edibility. Lower costs for retailers may also eventually lower the cost of food for consumers."

Read more low-cost sensor that detects food spoilage at Imperial College London