Could This Tiny Sensor Make Food Sell-by and Expiration Dates a Thing of the Past?

Still confused about when you should you pour that gallon of milk down the drain or how long a hunk of tofu is good once it's been opened? If so, you’re not alone. Researcher have found sell-by and expiration dates on foods to be pretty arbitrary, but there’s still plenty of confusion about how long we can keep an item around before it spoils. The result: Americans chuck nearly half their food in the garbage every year.

But if a project by chemists at MIT pans out, in the future all we’ll need to do to figure out whether that cantaloupe is still fresh is stick a sensor that can be read by a smartphone into the fridge. Of course, these aren’t just any old sensors—they’re made using tricked-out near-field communication tags, which are essentially tiny wireless bar codes.

The MIT researchers modified the tags so that they are able to detect gases in the air. Foods that are beginning to spoil begin to emit fumes, whether a gaseous ammonia or hydrogen peroxide, which the sensors can then pick up. The sensors then wirelessly transmit data to a person’s smartphone. Just imagine getting a text message from your fridge letting you know that the bunch of kale you’ve been meaning to steam has seen better days.

“The beauty of these sensors is that they are really cheap. You put them up, they sit there, and then you come around and read them. There’s no wiring involved. There’s no power,” said Timothy Swager, the John D. MacArthur Professor of Chemistry at the school, in a statement. “You can get quite imaginative as to what you might want to do with a technology like this.”

MIT’s effort isn’t the first to try to find a technological solution to the sell-by and expiration-date conundrum. A student-created packaging label called the Bump Mark won this year’s James Dyson Award. Once a food starts to spoil, bumps appear on the label, letting a consumer know that it is time to get rid of the item.

Of course, given how jam-packed with food some Americans’ refrigerators are, the challenge the MIT researchers still have with the sensors is refining the technology so that the devices can tell whether it's the carrots that need tossing or the package of half-eaten lunch meat that’s hidden on a back shelf. But with such promising developments popping up all over the tech landscape, the end of confusing sell-by labels seems to be in sight.