05 Jun 2019

A low-cost, smartphone-linked spoilage sensor for meat and fish packaging could replace use-by dates, say academics from the Imperial College of Science Technology and Medicine. It's thought that this could help cut food waste for both consumers and supermarkets.

These new laboratory prototype sensors, developed at Imperial College London, cost two US cents each to make. Known as ‘paper-based electrical gas sensors’ (PEGS), they detect spoilage gases like ammonia and trimethylamine in meat and fish products.

The sensor data can be read by smartphones, so that people can hold their phone up to the packaging to see whether the food is safe to eat.

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.

Dr Güder 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.

It's estimated that 60% of the food we throw away each year is safe to eat. Imperial academics hope their innovation will help reduce that number and reduce food waste.