How about they exchange the packet next time you bring it in? That sounds about fair. I know the difference between jerky and fungus, even whilst drinking beer. Why should they be punished because they didn't notice it when you didn't, either - and you were sticking it in your mouth!
You live in Honolulu and you've never eaten fungi? I take my hat off to you, as that's not easy to do. Loads of Asian foods have mushrooms of some variety.