Can’t stand the stench of rotten food? You may not have to stick your nose into potentially spoiled snacks much longer. Chinese scientists have invented gel-like smart tags that stick to product packaging, such as cartons of milk and cans of green beans, and alert consumers if they’ve gone sour. Gizmag reports that the tags contain a metallic compound called a nanorod that changes color over time from red, signifying 100% fresh, to green, meaning absolutely spoiled. The findings were presented on Monday at the annual meeting of the American Chemical Society, and preliminary results of the technique were published in ACS Nano.
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