My roommate disregards my fish allergy. What should I do?

[queensdouble14]

I'm normally a very flexible person, and I will tolerate all my roommate's eccentricities, but I feel that this crosses the line. She knows that I am severely allergic to fish, yet I opened the fridge last night after a week away from our place to find open packages of fish fillets on every shelf, in every pocket, and in the freezer. Sometimes, she cooks it while I'm in the apartment and my eyes begin to water and my throat gets very itchy. There's only one month left on the lease, and I'd prefer us to remain on good terms. What do I say to her and how do I say it without seeming rude?