My brother in law would have an allergic reaction when he eats shrimps with tripolyphosphate. His lips would be swollen and he would have a very hard time breathing.
I have been feeding my fish with frozen shrimps for a few years now. If you look at the shrimps closely, you can tell if the shrimps contain the chemical or not. Shrimps with the added chemical will look whiter and shinny then the regular shrimps. It also looks more clearer then opaque when you look at the meat. When cooked, the meat is more crunchy then chewy.