Should I charge my roommate for a meal she didn't eat?
Why do you need to charge her for something she didn't eat?
I'm tired of her bad attitude
Your roommate didn't want the food, so how is she responsible for the cost? That is just petty and selfish, she's not going to eat everything that she sees. You need to be more mature and let it pass and ask her next time if she wants to eat or not.
You don't know her, I'm sure she had a hidden motive
It still makes no sense to charge someone for something they did not want. If you have beef with her, confront her about it directly and let her know. Forcing her to pay for charges won't solve your dispute.