Fresh food packaging

Materials World magazine
7 Jun 2019

Sustainable and cheap sensors to detect the freshness of meat and fish have been developed by Imperial academics in a bid to cut down on food waste. Idha Valeur reports.

A new type of sensor for packaging could combat food waste by detecting spoilage, Imperial College London, UK, academics said.

According to the press statement, 60% of the food UK consumers throw out each year – worth £12.5bln – is due to overly cautious use-by dates and is actually perfectly safe to be eaten. These new sensors are hoped to curb excessive food waste by being implemented directly onto packaging at retailers.

The sensors are cheap – costing only two US cents to make – and work by identifying gases such as ammonia in fish and meat to monitor at one point the product is spoiled.

Known as paper-based electrical gas sensors (PEGS), information from the devices can be accessed by smartphones using near field communication (NFC) tags – microchips – to understand whether the food is safe to consume or not.

Keeping with the sustainability theme, all the materials used by the team from the university’s Department of Bioengineering are biodegradable and non-toxic. The sensors were made by printing carbon electrodes onto cellulose paper, which is safe for food contact.

‘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,’ Department of Bioengineering Dr Firat Güder said.

‘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,’ he said.

According to the researchers, during the testing of the sensors on packaged fish and chicken, the PEGS was able to pick up on gases faster and more precisely than other sensors.