Umm... yeah... I would never EVER collar correct or shock my dogs to get them to leave food on the ground. Why do something that you know for a fact will harm your dog, just to prevent a super freak, rare accident from happening? That is just backwards. But I would never harm my dogs for any reason, when there is always, always a force free method that works. And works better.
My dogs don't eat stuff on the ground, because I have taught them a very strong leave it with all food items on the ground, and practice regularly. I'll scatter tasty stuff all over the place, tell them leave it, and jackpot them from my hand for leaving it. Do recalls with a bunch of yummy chews and treats lined up beside them. Off leash at the park, they have ignored chicken bones and other nasty stuff. I don't leave my dogs outside alone. Poisoning is the least of my worries with a dog left out alone. Still, I honestly feel that my dogs wouldn't eat items on the ground, even Fozzie the piglet.
The trainer at my store taught her dog to leave food on the ground and animals alone from a long distance using an airhorn. It is much less damaging than a correction or a shock collar, IMHO.