The black layer that can sometimes be seen on salmon is called the bloodline or blood meat. It is a layer of blood vessels that run along the length of the fish between the salmon’s skin and flesh. The bloodline appears darker in color compared to the rest of the salmon’s pink flesh due to the high concentration of blood in that area.
What causes the bloodline in salmon?
All fish contain blood vessels that transport blood throughout their bodies. In salmon, there is a large blood vessel that runs the length of the fish’s lateral line. The lateral line is a sensory organ that consists of fluid-filled sacs with hair cells that detect changes in water pressure and movement. This major blood vessel branches off into smaller capillaries that supply the salmon’s muscles with oxygen and nutrients.
In some species of salmon, like coho and sockeye, these blood vessels are more concentrated in the area along the lateral line. This creates a dark red stripe along the length of the fillet. In other salmon species, like king and chum, the blood vessels are less prominent, resulting in a fainter bloodline.
Is the bloodline safe to eat?
Yes, the bloodline and blood meat in salmon are completely safe to eat. Here are some key points:
- It is made up of blood vessels and blood, which are edible parts of the fish.
- The bloodline is not a vein or artery. It does not contain blood that was “draining” from the fish.
- Cooking salmon to an internal temperature of 145°F kills any potential parasites, viruses, or bacteria present in the blood.
- The bloodline has the same flavor as the rest of the salmon. It does not taste “fishy.”
- Removing the bloodline is not necessary for safety. It is strictly an aesthetic choice.
So while some people find the appearance unappetizing, the bloodline can be safely eaten if the salmon is properly cooked. The red color may also fade after cooking.
Does the bloodline affect the taste of salmon?
No, the bloodline does not negatively impact the flavor of salmon. Here’s why:
- The bloodline is made up of blood vessels and blood, not connective tissue or sinew.
- It has the same mild, fatty salmon flavor as the flesh.
- Any “fishy” taste would be from poor handling/storage, not the bloodline itself.
- The color is purely cosmetic, not an indication of taste.
- Many sources say the high concentration of fat and blood make it the most flavorful part.
So while the darkened appearance may be unappealing to some, the bloodline offers the same great salmon flavor when properly cooked. It does not make the fish taste more “bloody” or iron-rich.
Should the bloodline be removed from salmon?
Removing the bloodline from salmon fillets is optional:
- It does not need to be removed for safety reasons if cooked properly.
- It can be removed if the appearance is unappetizing to consumers.
- Removing it may waste 5-10% of the fish since it runs the length of the fillet.
- Leaving it in provides more omega-3 fatty acids, iron, and added flavor.
- It’s easiest to remove before cooking when the color contrast is greatest.
In restaurants and seafood processing, the bloodline is often removed because some customers find the dark color unappealing. For home cooking, it can be left in or removed according to personal preferences.
How to remove the bloodline from salmon
Here are some tips for removing the bloodline if desired:
- Use a very sharp, thin-bladed fillet knife.
- Have the fish scaled, gutted, and filleted first.
- Lay the fillet skin-side down on a cutting board.
- Run the knife along the length of the red/dark stripe to cut it away.
- Trim off any remaining dark spots.
- Rinse afterward and pat dry.
- Remove before cooking, not after.
It takes some finesse, but the bloodline can be removed with careful knife work. Just follow the discolored stripe down the fillet. Alternatively, ask your fishmonger to do it!
What are some ways to cook salmon with the bloodline in?
Here are some cooking methods where the bloodline can be left on for added flavor and nutrition:
- Baked salmon – Bake fillets or a whole side of salmon.
- Grilled salmon – Grill skin-on fillets or steaks.
- Broiled salmon – Broil thick salmon steaks.
- Poached salmon – Poach whole fillets in liquid.
- Cedar planked salmon – Cook fillets on a cedar plank.
- Salmon en papillote – Bake in parchment paper.
- Salmon burgers/patties – Minced salmon can contain bloodline.
- Canned salmon – Retains the bloodline.
The bloodline will difuse into the flesh during moist cooking methods. Dry heat methods may cause it to look more pronounced unless charred.
What are some ways to cook salmon after removing the bloodline?
If the bloodline has been removed, here are some good cooking methods:
- Pan-seared salmon – Cook skin-on fillets in a hot pan.
- Blackened salmon – Coat fillets with a spicy blackened seasoning.
- Salmon sashimi – Thinly slice raw salmon.
- Ceviche – “Cook” raw salmon in citrus juice.
- Smoked salmon – Hot or cold smoke trimmed fillets.
- Gravlax – Cure raw salmon in salt, sugar, and dill.
Cooking methods where the salmon is not cooked through or is served raw will benefit the most from bloodline removal. The contrast in color will make the final presentation more appealing.
Is bloodline removal necessary for sushi and sashimi?
For raw preparations like sushi and sashimi, it is best to remove the bloodline:
- Provides a better appearance since the fish is raw.
- Allows for evenly-shaped cuts required for nigiri/sashimi.
- Enhances the mild flavor by removing the bloody taste.
- Prevents a chewy or rubbery texture in the blood vessels.
In Japan, sushi chefs are specially trained to remove all bloodlines, tendons, and discolored portions when preparing salmon for sushi and sashimi. This produces clean cuts with the ideal texture.
Does cooking salmon kill parasites in the bloodline?
| Parasite | Killed by cooking to… |
|---|---|
| Anisakis simplex (worm) | 145°F |
| Diphyllobothrium latum (tapeworm) | 131°F |
| Salmon Poisoning Fluke | 145°F |
Yes, cooking salmon to proper temperatures is effective at killing any potential parasites:
- Anisakis simplex dies at 145°F – can infect bloodline area
- Diphyllobothrium latum dies at 131°F – not in bloodline
- Salmon poisoning fluke dies at 145°F – not in bloodline
As long as salmon reaches 140-145°F internally, it is safe to eat regardless of bloodline. Freezing salmon can also kill parasites prior to cooking.
Conclusion
The dark bloodline found on salmon is safe, edible, and provides added flavor and nutrition. While its appearance may be unappetizing to some, it does not affect taste or require removal. Cook salmon properly to 145°F internal temperature to kill any potential parasites present in the bloodline. Removing it is optional and often done for aesthetic purposes in restaurants and raw preparations. For home cooking, the bloodline can be easily left in to take advantage of its benefits without any safety concerns.