Researchers discover sensors which can detect food spoilage

A recent study discovered new sensors which could help in detecting food spoilage and reduce wastage of food for supermarkets and consumers.

The laboratory prototype sensors which can be read on smartphones are known as 'paper-based electrical gas sensors' (PEGS), they detect spoilage gases like ammonia and trimethylamine in meat and fish products.

The researchers, who developed PEGS, made the sensors by printing carbon electrodes onto readily available cellulose paper. The biodegradable materials are eco-friendly and non-toxic, 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.

Lead author, Dr Firat Guder, said, "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. Our vision is to use PEGS in food packaging to reduce unnecessary food waste and the resulting plastic pollution."

The researchers hope to expand the usefulness of PEGS by applying them to other types of food and industries. They are currently developing an array of PEGS in which each sensor detects a different chemical. Using this technique, the array will give unique signals for different gases and/or changing humidity, which would make the technology applicable to a wider variety of food types and applications.