Making sure fresh food is kept at the right temperature during transit is a harder problem than one might think — but the Swiss are on the job. A research team has created a biodegradable temperature sensor that sticks to food all the way from its starting point to the inside of your mouth.

The issue in an nutshell is that it’s a pain to manually test food that needs to stay at a certain temperature, but if you can monitor it constantly and wirelessly, you can save time and energy.

You can do that right now, in a way, with RFID tags and so on — but those tags use metals that aren’t recommended for eating, and may even be poisonous. The solution arrived at by Giovanni Salvatore, a researcher at ETH Zurich, is to make an ultra-thin sensor out of materials that a human can digest safely.

Today he and his team published their work in the journal Advanced Functional Materials. They managed to build a sensor that’s only 16 micrometers thick — for comparison, a human hair is 100 micrometers or so. This filament is made of magnesium, which ETH Zurich says in its news release is “an important part of our diet.” Sure, why not.

Also used are silicon dioxide and nitride, which are harmless, and a compostable polymer made of corn and potato starch holding it all together. The whole thing can be bent, stretched, even crumpled up and it’ll still work.

Shippers will put a few of these on some randomly selected apples, bananas, etc, and put them in the truck or boat. You can then check the actual temperature of the food from outside the refrigerated compartment.