This Is Why You Want to Take the Dark Meat Out of Your Fish
by Owen James Burke
This is the secret to not only making fish taste better, but avoiding poisoning. Photo via Commuter Cruiser
I’ve always pulled the dark red meat (brown, once cooked) out of fish before cooking it, if not after. It’s what some people call the blood line, the set of nerves that make up a fish’s lateral lines, and it’s often what gives fish that undesired fishy or earthy taste. Certain fish, like bluefish and tuna, contain more of it than others, while milder fish like snapper and cod have relatively thin blood lines (in the past, I haven’t bothered to remove theirs). But there’s another, more critical reason to remove this dark pungent layer: it could be poisonous.
Scombroid toxin is a bacteria-borne poison that occurs in the blood line of more oily fishes when they’re mishandled before consumption. These fish include (but are not limited to) tuna (all species), amberjack, bluefish, kahawai, sardines, herring, mackerel, wahoo and mahimahi, to list a few.
According to Charles Patrick Davis, MD, PhD on emedicine, symptoms vary from person to person, but common symptoms include nausea, diarrhea, vomiting, headaches, flushing, fever, hives, abdominal cramps, unusual heart-pounding sensations, and burning or itching in the mouth, which can last for up to a few days.
Like ciguatera, another toxin commonly found in fish (though symptoms of ciguatera tend to be far more acute and prolonged), scombroid is tasteless and odorless, and there’s really no tried and true method of testing for the toxin. Scombroid poisoning is nowhere near as debilitating or threatening as ciguatera, which is one of the single-most dreaded seafood poisonings, which can either make one feel ill for a couple of days or deteriorate them in the slowest, most excruciating combination of the above symptoms for months, perhaps years. Some have even attributed ciguatera poisoning to death, but the toxin and its effects are still such a mystery to medicine that it hasn’t been confirmed.
All horrors aside, it’s still perfectly safe to eat these fish, but take the two minutes and not only will you feel more at ease, your fish will taste better. If a fish is very carefully handled and kept on ice or in a freezer from the moment it’s caught, the bacteria should not develop, but it’s well worth taking this quick, precautionary measure:
Firstly, you should do this with all fish, even those that you’ve purchased from your local fishmonger (if they haven’t done it for you already). You can remove the blood line from most fish by cutting a triangular-shaped wedge apexing somewhere in the middle of each fillet. It runs along the lateral lines of the fish, on either side of the spine, and although the depth and size of is different in every fish (see the youtube video below for striped bass), it usually doesn’t require too deep of a cut. Make slow cuts to find out where it ends to ensure that you don’t remove any of the good flesh. Larger fish like tuna, however, tend to have very deep blood lines and you’ll find yourself removing several pounds from the fillets (or loins) of larger fish, but don’t feel bad, it could put you on the can for a few days, and nothing is worth that.
Read more about ciguatera, another, more dangerous toxin found in seafood, here. — OJB