Researchers at a Canadian university have developed a patch which shows if food is past its best.

With the McMaster University patch, instead of relying on use by dates, customers get a definitive answer to whether or not their food item is fresh or not. The transparent patch can be placed inside packaging, alerting consumers to any problems via a  smartphone or other device.

“In the future, if you go to a store and you want to be sure the meat you’re buying is safe at any point before you use it, you’ll have a much more reliable way than the expiration date,” explained lead author Hanie Yousefi, a graduate student and research assistant in McMaster’s Faculty of Engineering.

Labelled Sentinel Wrap, after a cross-discipline research network at McMaster, the patch – made with ‘harmless molecules’ – doesn’t affect the food.

“A food manufacturer could easily incorporate this into its production process,” added Tohid Didar, a mechanical-biomedical engineer and member of the McMaster Institute for Infectious Disease Research.