How do I deal with my other half's horrible table manners?

I love my girlfriend very much, but it really disturbs me (and turns me off) that she has zero table manners. I've tried to talk to her about this but she just gets offended and wants to discuss things that aren't perfect about me instead. That is fine with me but when she sees that I'm not going to run from that either she gets mad and stomps off, then silent treatment. Some of the things she does at the table that totally annoy me are: Eating at top speed (seriously), slurping every chance she gets, chewing with her mouth open, shoveling more food in when she already has a full mouth, biting the fork or spoon and most of the time scraping it across the teeth on the way in and out of her mouth. Oh yeah, then there's the belching and farting. She does say excuse me on those 2 things but I don't find it any less gross and it happens repeatedly at every meal, all of those things. Help me please! I need to find a way to approach her so that she is not upset with me but understands that this has turned me off.