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Scientists Create Smart Labels To Tell You When To Throw Away Expired Food and Makeup (sciencemag.org)
At the 254th National Meeting and Exposition of the American Chemical Society, researchers are presenting a low-cost, portable, paper-based sensor that can let you know when to toss food and cosmetics. The sensor can detect antioxidants in tea and wine, and be used to explore remote locations, such as the Amazon rainforest, in search of natural sources of antioxidants. "I've always been interested in developing technologies that are accessible to both industry and the general population," Silvana Andreescu, Ph.D., says. "My lab has built a versatile sensing platform that incorporates all the needed reagents for detection in a piece of paper. At the same time, it is adaptable to different targets, including food contaminants, antioxidants and free radicals that indicate spoilage." Phys.Org reports: What sets Andreescu's sensors apart from others, she says, are the nanostructures they use to catch and bind to compounds they're looking for. "Most people working on similar sensors use solutions that migrate on channels," Andreescu says. "We use stable, inorganic particles that are redox active. When they interact with the substances we want to detect, they change color, and the intensity of the change tells us how concentrated the analyte is." Additionally, because all of the reagents needed to operate the device are incorporated in the paper, users don't need to add anything other than the sample being tested. The American Chemical Society has published a video detailing the sensor. Their paper has been published in the journal Analyst.
Expiry dates don't really work. You can't know in advance when food is going to go bad, because it depends very, very heavily on things like the conditions under which it has been stored.
Actually, the ordinary person's sense of smell and taste is incredibly good at telling if food is inedibly spoiled.
With only a tiny number of exceptions, if food smells OK and doesn't taste funny, it's safe.
I am a scientist, and I work on chemical sensors.
Colorimetric sensor arrays are not new by any stretch of the imagination. There are several companies that make and sell them, many using "nanostructures" to boost something (usually the markup). We've been through food freshness, fruit ripeness, coffee roast detection, wine quality... Some of these are worth the $0.05 sensor and $1.00 labor required to package with the food, and some are not, but detecting these things is not a problem.
More and more, I'm seeing academic scientists demonstrate a lack of understanding of what real world problems and opportunities are. Someone in the academic grant backed research machine needs to have an eye on what's happened prior to recently published literature (and maybe look at what happens outside the literature too). 15 years seems to be the horizon of forgetfullness.
Eat a couple bites of it and if it causes me to keel over and have to go to the emergency room, then it is probably not a good idea to eat the rest unless it is tasty.