I'll admit, I used to try and sneak things in on family members who said they didn't like XYZ. Sometimes it works...more often than not, it didn't, and my family would get mad at me for trying to make them eat something they knew they didn't like.
Now I just ask them nicely to try things... and amazingly enough, when you ask people nicely to try something, they usually say yes, especially if they trust you.
Side note, I like that you're avoiding giving your mom a piece of your mind...when she obviously didn't feel too bad giving you a piece of that animals mind to munch on. Icky.
I think that you have every right to be mad, and to let her know about it. She shouldn't feel like it's OK to trick you, because it's not. If she asks you in the future if you would like to try something she's made, politely tell her no, because you don't know that you can trust her.