Why does my dog hate it when I touch his food?

Your dog is not necessarily "hating it" when you touch his food. Nor is he being "mean." He is communicating with you. What he is saying is, "This is MY food. Leave me alone while I eat it." Is this a problem? You bet it is. It's a big problem. It means your dog is alpha over you. There are different levels of dominance and even if your dog has never bitten, always keep in mind that growling or the bearing of a dog’s teeth eventually does lead to biting. It is time you reassess your human to dog communication skills and take the alpha position away from your dog before it escalates into a larger problem.