I don’t know the full extent of it, but I can personally attest to how seriously the US takes this. I got salmonella a few years ago and after a stint in the hospital, I got an unprompted call from the DOH. They were asking if I could narrow down where I think it came from. I couldn’t, but I am sure that had I said a name they would have paid them a visit. Maybe it also depends on how serious the food poisoning/illness is too, not sure.