I'm a future BARFer/Pitcairn/Schultze/Lonsdale, depending on my dog's preferences. Honestly, I think the answer is simpler than "detox" or bacterial contamination. Quite frankly, when a kibble fed dog is introduced to a raw bone....They love it! That is, if you give a recreational bone to a normal healthy dog, the dog will most likely grab it from your hands and run to it's safe place and just go crazy over it. To the loving owner, this gives them a sense of relief and gratitude. However, the kibble fed dog should never be given a raw rec bone for a prolonged period of time. Why? No matter what change you give a dog, the flora of a dog's GI tract is disturbed. When you introduce a bone with, presumably, a lot of marrow, the dog ingests more than his/her GI tract can handle. It goes for any dog, raw fed or not. Thankfully, Giselle has an iron stomach and she can safely chew on a rec bone for as long as she wants. She can bury it and let those wonderful enzymes overtake her rec bone and dig it back up to eat later on. I don't think it has anything to do with bacterial contamination so long as you safely handle it and buy it from a butcher deemed safe for humans. Heck, if I eat too many spicy things, the same happens to me (although that was a little too much info, eh?).