Scientists create smart labels to detect when food has gone off and should be binned The days of allowing food to pass its best and accidentally eating it could soon be over, thanks to pioneering […]

The days of allowing food to pass its best and accidentally eating it could soon be over, thanks to pioneering new methods presented by scientists to the world’s largest scientific society.

Researchers at Clarkson University, New York, have created small paper sensors capable of detecting when food is no longer safe to eat due to the level of contaminants, antioxidants and the free radicals which indicate spoilage.

The paper changes colour once it comes into contact with ruined food, with the intensity of colour change indicating the severity of the spoilage. Future versions of the labels could be developed to identify potentially dangerous bacteria, including salmonella and E. coli, team leader Professor Silvana Andreescu said.

The i newsletter cut through the noise Email address is invalid Email address is invalid Thank you for subscribing! Sorry, there was a problem with your subscription.

The sensors could also be used in the cosmetics industry to warn consumers when a product is no longer safe to use. While makeup can be kept unopened for around three years, mascara and liquid eyeliner should be replaced every three to six months to minimise the risk of eye infections.

Such indicators could go some way to combating the UK’s significant food wastage. The average British family throws away £700 worth of food each year, equating to around 350,000 tonnes across the country annually, according to the Waste Resources Action Programme (wrap), the government’s food waste group. It estimates around half of us bin food that’s still safe to eat due to eat due to ‘misleading’ use-by dates.

The project was presented as the 254th National Meeting & Exposition of the American Chemical Society, where Hayriye Ünal from Sabanci University in Turkey also presented a form of food packaging film designed to extend its shelf life by preventing over-ripening and rotting.

Ünal’s team created a packaging film coated with clay nanotubes containing a natural antibacterial essential oil found in thyme and oregano. The tubes absorb ethylene, a compound released by fruits and vegetables as they ripen, while retaining water vapour and other gases and preventing oxygen from entering the membrane. The oil kills microbes, halting bacterial growth.

To test the clay film, the researchers wrapped chicken, tomatoes and bananas in the specialised wrap and standard polyethylene wrap. After 10 days, the tomatoes were and bananas were firmer and better preserved than their less-protected counterparts, while the specially-wrapped chicken showed “significantly less bacterial growth” compared to the meat in the polyethylene after being refrigerated for 24 hours.

“Food packaging that is capable of interacting with food can contribute to safety and prevent economic losses from spoilage,” said Ünal. “Specialised films that can preserve a wide array of foods are highly sought after.”

The team now plan to test the film to ensure it is non-toxic, and that it is safe for humans to eat food which has been wrapped in it.