When you're standing in the frozen food aisle, it's nearly impossible to know whether that Salisbury steak has thawed and refrozen -- a process with potentially harmful consequences. So, researchers have now designed a food-grade device from edible materials, including table salt, red cabbage and beeswax, that lets you know. The proof-of-concept sensor provides a color readout when it's warmed above a specific temperature, which is tunable from -58 F to 32 F.

https://www.sciencedaily.com/releases/2022/10/221012103215.htm

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