What can i do about my dog eating the cat food?

I have a dog and 3 cats. The cats and the dog eat in the kitchen and they dont have a set eating time, we usually just put their dishes out and fill them up whenever they are near empty. This is the problem, the dog has a dish and the cats share one but when the cat food is on the ground the dogs starts to eat it. We were forced to move the cats food to the table in the kitchen which isnt necessarily the most sanitary thing. What can I do to keep the dog from eating the cat food?