Say you’re sitting in a Starbucks and see a teenager who looks just like that picture on the missing-child poster you scanned with your smartphone in Safeway two weeks ago. But you’re not sure, so you ...

Say you”re sitting in a Starbucks and see a teenager who looks just like that picture on the missing-child poster you scanned with your smartphone in Safeway two weeks ago. But you”re not sure, so you ...

QR codes containing all the information of the dairy and a unique alphanumeric identification code are placed by law on every wheel of Parmigiano-Reggiano cheese (Photo by David Silverman/Getty Images ...