Hi there, It's not so much a case of "training" but asserting your superiority in the pack over the dog. This is an issue that goes beyond just the bone but it is key to your total relationship with your dog. You should be able to take the bone (or any food) off your dog. This is quite important if they've got something they shouldn't have!
I thoroughly recommend the dog listener (Jan Fennell). Here's a link to her website
http://www.janfennellthedoglistener.com/. I suggest you get one of her books - your local library may have one. She has really figured out the doggy mentality. She and Monty Roberts are on the same wavelength.
Good luck in building a happy healthy relationship with your dog.