You've gotten lots of good advice. I can only share what has worked for me. Our boy Rufus is food aggressive and we have 3 other Greys as well, all of whom have been bitten by Rufus over food.
The routine now is, anything that has to do with food - dog food or people food - Rufus gets muzzled. For dog feeding time, I gate Rufus in the dining room with his muzzle on. It is adjacent to the kitchen so he can see what's going on. When the food is ready and Rufus is calm, I take off his muzzle, put his bowl down on his side of the gate and walk away. When everyone is done eating Rufus gets let out.
I've been battling Rufus over this for almost 5 years. It's gotten better, but now and then one of the other dogs was still getting bitten. So I finally gave up trying to train him out of it. It wasn't fair to the other dogs because Rufus would be good for six months or so and then someone would get chomped. So I just changed the routine and came up with a method where Rufus simply isn't able to bite anyone over their food any more. Once meal time is over he's fine, so this has been the best solution. We just had a friend stay with the dogs for four days and i left her detailed feeding instructions. She followed them and had no problem. So, while I haven't figured out how to resolve Rufus's issues, I have figured out how to avoid them. And I guess that's the next best thing.