this is the WORST thing you can do with a food-guarder- you just taught the dog he has a real reason to guard his food, because you ARE going to take it away, and now he'll guard even more aggressively. Many people have turned mild cases of guarding into seriously dangerous dogs by punishing the guarding behavior.
I'll add that he needs to learn NOW that food aggression is not acceptable. Going for your hand when you take his food? No way. A guttural UH-UH (mama dog grunt) along with, if needed, scruffing his neck (mama dog discipline). Don't lose your temper, don't make a big deal or yell. Simple, firm, no-doubt-about-it, impersonal & effective discipline. If you reach for the food you get the food. He must never drive you away by aggression from anything you want to do.