I have a bunch of earplugs I got (on sale) that are "detectable" - they have a small steel rivet in them; the idea being that if you are manufacturing food on

I have a bunch of earplugs I got (on sale) that are "detectable" - they have a small steel rivet in them; the idea being that if you are manufacturing food on an industrial scale, you don't want some poor bastard finding your lost earplug in her "Hungry Man" dinner, so they just run 'em through a metal detector on the way out as part of the QC process. I bet you could do the same thing with fresh food, but I'm not sure it would be worth it. If nothing else, I don't think your typical metal detector is going to detect copper. For my money, I'd like my local food-serving establishment to put the effort into hygiene.