How to make my friend stop insulting me?

I have this friend who doesn't outright insult me, but at our lunch table she says, "Hey have you guys noticed that (my name) is really bad at this, or doesn't know how to do this, or has this really bad habit, you know, just saying" and it bothers me a lot. Recently, she has been doing this quite frequently and it is really starting to hurt my self-confidence, which isn't very high to begin with. I don't want to be rude and say something too snippy because everyone else at my table thinks it's a joke or no big deal, but I want a polite way to shut her up for good, because it's really annoying and makes me feel self-conscious. I try to keep my distance from her but we are a part of the same friend group so it's hard to completely stop seeing her. Sorry this is so long, but thanks for the help(: