Coming Soon: Smart Tags That Change Color When Food Goes Bad

American Chemical Society

The clock ticks by as your food nears its expiration date...but it won't be a mystery anymore with these smart tags that are smarter than printed expiration dates.

You may never have to accidentally consume sour milk or chunky yogurt again. Scientists at Peking University in Beijing have developed and tested smart tags used to label food that will change colors as the food or drink item starts to go bad, according to CBS. They have the ability to spot spoilage even before a can or jar is opened and sniffed through a technological compound made out of mostly gold and silver called nanorod. Nanorod is naturally red, but changes color over time as other compounds gather on the substance. Scientists have timed these nanorods to match the expiration date of the food it’s attached to, as well as any environmental or technological changes or glitches that a pre-stamped date can’t detect.

The Peking University scientists have already successfully tried the nanorod technology on milk.

"We successfully synchronized, at multiple temperatures, the chemical evolution process in the smart tag with microbial growth processes in the milk," lead researcher Dr. Chao Zhang, a scientist at Peking University in Beijjing, said in a statement.

Basically, these small, gel-like tabs (which scientists say will be affordable for the average consumer), change color from red (100 percent fresh), to orange (approximately half of the shelf life is left of the product), to yellow (iffy), to green (expired).

Dr. Zhang did not respond in time to requests for comment, so no word on when these smart tags will hit stores.

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Joanna Fantozzi is an Associate Editor with the Daily Meal. Follow her on Twitter @JoannaFantozzi