Food-testing circuit could eliminate waste

Plastic electronics that can test whether food is safe to eat can greatly reduce food waste worldwide, researchers in the Netherlands say. Millions of tons of food are thrown away each year because the "sell by" date has passed. However, the listed date is a cautious estimate, which means a lot of edible food is thrown away, scientists at Eindhoven University of Technology said. Working with European colleagues, they have developed a plastic analog-digital converter circuit that could make in-package food testing possible, they said. Such circuits could cost less than a penny each, they said, making them economically viable as a food testing aid. For example, food producers could include an electronic sensor circuit in packaging to monitor the acidity level of the food, the researchers said. Such sensor circuits could be read with a scanner or with a mobile phone to show the freshness of the food or whether it was defrosted, they said. "In principle that's all already possible, using standard silicon ICs," Eindhoven researcher Eugenio Cantatore said. "The only problem is they're too expensive. They easily cost 10 cents. And that cost is too much for a 1 euro bag of crisps. "We're now developing electronic devices that are made from plastic rather than silicon. The advantage is you can easily include these plastic sensors in plastic packaging." The plastic semiconductor can even be printed on all kinds of flexible surfaces making them cheaper to use, he said, and means sensor circuits costing less than 1 cent are achievable.