how do you tell someone to quit feeding your dog "human" food, without being rude?

I've got the same situation. I had to move back in with my parents and I thought they would make me get rid of my animals. I had to give my cat up so my grandfather is doing me the favor of taking care of him until I can get my own place. My parents love my dog though. They feed her anything they are eating. I keep trying to tell them that its not safe for her because she is so small. They have a Rottweiler that eats EVERYTHING from chicken bones to raw meat sometimes. For some reason my father thinks raw meat every once in a while is good for dogs. Dont know if its true or not. I have fought with them for months but they still have not stopped. My Amaya will no longer eat dog food. Her food stays in her bowl until someone throws human food in there. She has gotten a bad habit of begging at the dinner table. She doesnt do it to me because she knows I wont give her any food. My parents started to sneak it behind my back but I know what they've done when I have to clean up the nasty "messes" Amaya leaves behind. The only thing I can do at this point is keep saving money and looking for a house of my own.