Some finfish, including grouper, snapper, mahi-mahi and dolphin may be the source of a toxin called ciguatera. This toxin is present in tropical reef areas where these fish are harvested. However, a careful fisherman will not fish from reef areas that are likely to be a source of ciguatera. Using a good seafood dealer with a reputation for quality will help you to avoid this toxin. Spoilage Spoilage is caused by bacteria, enzymes and chemical changes in seafood.
Spoilage can begin as soon as seafood is harvested.
Spoilage organisms are not the same organisms that cause illness. Spoiled fish can smell bad, be slimy, or rancid. All of this makes the seafood unappetizing, but not necessarily unsafe. However, spoilage can be a sign that the seafood has been mishandled, or that it is old. Pathogens can multiply quickly in fish that has not been handled carefully.