If its a breed that is likely to be problematic, you start by hand-feeding them from their bowls when they're babies, so that they're used to you being around while they eat and they're used to your hand in their bowls. When I was younger, I had a cocker spaniel and lots of nieces and nephews. Easiest thing is to keep the kids away from the dog, but in a household the size of my parents' that's not always possible. I taught my dog to tolerate having his bowl taken away by doing it and giving it back immediately. You can also give it back with something really yummy in it that wasn't there before. If the dog expects that you'll add something, he's less likely to complain about giving it up for a second or two. Satin never growled at me over his food, but he would sometimes put his nose in the bowl and pin it to the floor to keep me from taking it. *giggle*
What I did with Cash, I don't really recommend. It didn't occur to me that it would be a problem, so when he growled at me at 6 months, I spoke harshly to him, took the bowl away, and made him do doggie sit ups to get it back (sit, down, sit, down, sit "good boy!"). Just taking the bowl away like that is risky, but I was pretty perturbed that he'd growled (I also at that point had a reliable sit and down on the dog and knew he'd do what I asked). I then made a habit of approaching him while he ate, taking his bowl, telling him how good he is, and giving it back. He doesn't like it, but he doesn't threaten me anymore, either. In fact, he usually pulls his head up as soon as I approach and waits for me to go away. If he does that, I don't bother to touch his bowl. I just tell him he's good and go on about my business.
Harry growled at me once when he was in his crate with his bone. I made him come out of his crate by speaking harshly to him (I would have tipped the crate over if I'd had to, but NEVER reach into a dog's crate after him - that's a guaranteed way to get bitten), then took the bone from him and made him do sit ups. He's never growled at me over anything again. But as I said elsewhere, Harry has an almost perfect temperment and he's smart. Cash is neither as perfect nor as smart (but I love him better). *grin*
Elizabeth