Growling when people take a treat/bone of a dog is a dominant behavior , which is never allowed in my home, and no one should alow it.
Fido has never growled at be for taking a bone of him

but the yorkie bitch I sometimes babysitt does that, she doesnt want me taking the bone of her, I just take it from her whatever she says, thats the best way, and if the dog lets you take the bone/treat then you compliment him/her very much and maybe let her have it again
It is VERY important to take the food and bone from the dog sometimes while he's eating it,and if he lets you have it with no proplom you compliment him very much and let him have it again, thats the best way, I did it with Fido since he was a puppy