Does anyone know anything about STP- sodiumtrypolyphosphate.(i think) It is a preservative used in fish. I always thought I was allergic to fish, flesh fish. I can eat shellfish. Then one day at a fish market the man told me it was not the fish it was this STP. I am able to eat sushi and fresh caught fish like trout. He said sushi grade fish does not have any preservatives because it is to be eaten raw and the preservatives would mask it not being fresh. This all makes sense but what I want to know is if there is any source to get fish without this STP. I love fish and when I feed it to my family it kills me not to be able to eat it.