I would try to stop the growling immediately! I was told you should always put your hands down around their food and try to take away things they are chewing on...to get them us to it. (also, to have your children do this..so the pup won't care if their hands are around food and other things they like) My pup growled at me when she had been given her first pigs ear. I specifically put my hands down to take it out of her mouth and she growled so I said no growling..and kept taking it away and then giving it back..till she didn't growl. I probably held her mouth shut tight and said no growling as well.