Parmigiano Reggiano makers embedding tiny trackers in rind to fight cheese fraud
I found technical details about the device:<p><a href="https://www.isenet.it/product/pharmaseq-products/" rel="nofollow">https://www.isenet.it/product/pharmaseq-products/</a><p>It's tiny (500 microns), passive, photocell-powered (you point a laser at it), and encapsulated in an inert SiO2 coating.