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What If The Milk Container Told You When The Milk Was Bad?

Most expiration dates are total guesses. Now the packaging can tell you when it’s actually time to throw it out.

What If The Milk Container Told You When The Milk Was Bad?
[Top Photo: kubais via Shutterstock]

Food waste is partly a communication problem: Even after its “best by” date, your milk probably isn’t actually expired. The label (along with “sell by,” “best before,” and “enjoy by”) has nothing to do with food safety. It’s just a somewhat arbitrary sign of how long a manufacturer thinks it might taste best–but consumers tend to take it as a sign to toss food out.

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Packages of the future may be able to chemically monitor food to determine how long it’s really safe. Researchers at the University of California-Berkeley recently built a prototype of a smart, reusable milk cap that uses sensors to detect when milk starts to go bad. As bacteria grows in the milk, a wireless reader senses electrical changes and could eventually send updates to an app.

“One day you might be able to use your cell phone to detect the freshness of the product you are buying, instead of trusting the expiration label on the product,” says Liwei Lin, a professor in UC Berkeley’s mechanical engineering department.

The researchers built the cap as an experiment in 3-D printing electronics–most 3-D printers only make simple plastic parts, not complex gadgets. But by injecting liquid metal paste into a simple frame, the new process can make basic electronic parts that connect into a full wireless sensing system.

It’s cheap enough to do that this kind of package could eventually be widely used and even something that people could make at home. “Similar to printing out papers by using regular printer at home now, we should be able to print out this smart cap sensor and other electronics by 3-D printers at home in the future,” Lin says.

And perhaps it could help make a dent in the 20 pounds of food that the average American consumer throws out each month. Current labels are often based on worst-case scenarios; manufacturers might imagine how food might be mishandled, making it degrade faster. This packaging can monitor what’s really happening–and if you accidentally leave food out of the counter, or your electricity goes out, you’ll have a clear indication if the food is still fresh.

Another label, called the Bump Mark, is a low-tech variation that degrades along with food, creating a pattern of disappearing bumps when something goes bad.

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As food safety technology develops, some argue that a simple sniff can work almost as well–and that we should just get rid of confusing labeling. In the U.K., the government now suggests that companies only list “use by” dates, and take everything else off packages.

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About the author

Adele Peters is a staff writer at Fast Company who focuses on solutions to some of the world's largest problems, from climate change to homelessness. Previously, she worked with GOOD, BioLite, and the Sustainable Products and Solutions program at UC Berkeley.

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