Fecal platter

The Black Line in Shrimp Is Actually Its Poop. Is It Unsafe to Eat—Or Just Gross?

We asked scientists what the deal is and how to avoid getting sick.
Is the Black Line in Shrimp Its Poop and Is It Safe to Eat
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Your shrimp arrives at the table. You’re salivating, ready to dive in. But then your gaze narrows in on the thin black line along the backs of each shellfish. And suddenly, the excitement of tearing into some prawns dissolves as the question bubbles up: Is that…shrimp poop? And perhaps even more importantly, is it okay for you to eat it?

Personally, the thought of poopy seafood is enough to turn my stomach, but before it swore me off shrimp, I wanted to connect with food safety experts to understand what’s actually going on. Is that dark line really what it looks like? And if so, is eating it really something to worry about? Before you get too alarmed, read on to see what the pros have to say.  

What’s that black line in shrimp? 

The dark line running through the backs of shrimp goes by many names—the dorsal tract, back vein, or sand vein, Tori Stivers, MS, a seafood specialist at the University of Georgia Marine Extension and Georgia Sea Grant, tells SELF. The marking is made up of the shellfish’s stomach, midgut, and intestine. Those structures support the crustacean’s digestive process, so yes, that black stuff is the shrimp’s waste, she says. 

As for what you’re actually seeing there? Shrimp are called bottom feeders for a reason: They munch on foods found in the muddy depths of the ocean, like plankton, worms, microscopic animals, and various types of organic debris like sand. So that black line is likely a combination of all those things in various stages of digestion, Dave Love, PhD, a senior scientist at the Johns Hopkins Center for a Livable Future, tells SELF. 

Can eating shrimp’s poop make you sick?

Okay, now that we’ve established the dark line is the shrimp’s intestines—okay, yes, its poop—should you worry about eating it? While it may seem a bit icky, the general consensus is that it doesn’t pose a health risk…provided that you prepare it the right way.

“Eating the shrimp’s digestive tract doesn’t make you sick—as long as you cook it thoroughly,” says Dr. Love. That means steaming, baking, frying, or whichever way you’re craving it, until it reaches 145°F. At this internal temperature, the shrimp will take on a firm texture.

That’s not to say you can’t get sick from eating shrimp in general. You certainly can, but the food poisoning risk related to shellfish typically comes from eating it raw or undercooked, says Dr. Love. For instance, just like ground beef, raw shrimp can contain bacteria like E. coli. But if you cook it thoroughly, the heat will kill off the bacteria, as well as other potentially harmful pathogens that may be lurking, before it could wreak havoc with your digestive tract. So if you’re eating shrimp with the vein intact, you may want to skip the raw shrimp sashimi and go for them in a curry, stir-fry, garlicky pasta, or zesty taco instead. 

So, do you really need to devein shrimp?

Deveining shrimp refers to removing the dorsal tract—the digestive system—from the crustacean’s body. But if it’s not going to make you sick (in light of cooking the shellfish adequately, of course), do you really need to spend your time doing it? 

It’s really a personal preference. The dorsal tract occasionally contains sand, and if you leave it, you may get a gritty bite or two, says Dr. Love. So to have better-tasting, smoother shrimp, it’s wise to remove the waste, he says.

The process is pretty simple, Frank Costantino, the dean of the Culinary Institute of New York at Monroe College, tells SELF. The quickest way to remove the dorsal tract is to use a pair of kitchen scissors ($10, Amazon). Cut a slit along the back of the raw shellfish just into its flesh. Then use the tip of the sheers to pull the vein out. Run the prawn under cool water to get rid of any remaining crud, he says. 

It’s best to remove the digestive tract when the shrimp is still raw, since it will lift out easily. If you try to do so when it’s cooked, you’ll likely end up hacking away at your shellfish, losing valuable meaty parts of your prawn in the process. 

So if the black line still skeeves you out after reading this, make sure you ask the waiter how they serve their shrimp if you’re ordering them in a restaurant. Veins intact? You may want to change up your order. But if you’re on the fence, just take solace in that a little (fully cooked!) shrimp poop won’t hurt you—and dig into your plate whichever way the crustaceans come. 

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