Shop for and Prep Seafood With Care

Fish and shellfish can spoil quickly, and can be a source of food poisoning. Here's how to make sure you're getting the freshest seafood and keeping it safe.

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Seafood has a reputation as a wonder food, and for good reason. It's high in protein, often low in saturated fat, and the best way to get large amounts of heart-healthy omega-3 fatty acids. It doesn't take a lot to reap the health benefits, either: Two or more 3- to 4-ounce servings—about the size of a deck of cards—of most fish each week can lower your risk of heart disease, obesity, and cognitive decline, research shows. We should all be eating more of it.

But seafood is prone to fast spoilage and, especially when eaten raw, carries special food safety concerns. Our advice will help you get the health benefits of fish and shellfish while reducing the risks.

From sushi and ceviche to oysters and clams on the half shell, raw seafood is a staple in many cuisines. In Consumer Reports’ March 2023 nationally representative survey of 2,001 American adults (PDF), about half of people who eat seafood say they choose raw at least occasionally.

The concern: Cooking seafood to 145° F kills most germs that could be in the food, but when the food is eaten raw, dangerous pathogens can be present and make you sick.

For fin fish, the issue is mostly parasites such as roundworms, tapeworms, and intestinal flukes. Depending on the type, these parasites can work their way into your intestinal wall and cause nausea, diarrhea, or abdominal pain. Some can even migrate to your liver or heart and damage those organs.

For oysters, clams, mussels, and other shellfish, bacteria are the most common cause of food poisoning, particularly one called vibrio. It thrives in coastal waters, especially in warmer months, and can cause diarrhea, vomiting, and fever. Infections from it sometimes require hospitalization and can even be fatal.

CR's advice: Anyone who is pregnant, is younger than 5 or older than 65, or has a weakened immune system should simply avoid raw seafood, according to the Centers for Disease Control and Prevention.

Others can reduce, but not eliminate, the risk when preparing raw fish at home by carefully selecting seafood and making sure it's prepared properly.

For most raw fin fish, that usually means buying commercially frozen fish. That's because the parasites that can be found in raw fish can be killed only in temperatures below 0° F, says Michael Ciaramella, PhD, seafood safety and technology specialist at New York Sea Grant, a partnership with the State University of New York and Cornell University in Ithaca, N.Y. When you are ready to prepare the fish, thaw it slowly and, once defrosted, keep it very cold. And don't use the fish if it looks slimy or smells very fishy.

For raw shellfish, check for freshness. Bagged shellfish should have a tag indicating when it was harvested, and if shellfish isn't bagged, the store should have that information. Stick with those harvested no more than about a week earlier. Also do your own inspection: Shells should close tightly when tapped, and don't buy them if they are cracked. Use any shellfish you bring home within one or two days, and when the shells are opened, the meat should be firm.

When dining out at sushi and seafood restaurants, consider the establishment's reputation. Ratings and reviews on Google, Yelp, and similar sites aren't foolproof. But it would be wise to avoid places that have anything other than stellar reviews or that have even a few mentions of food poisoning. Some locations provide letter grades or color-coded placards to indicate recent food inspection results. "Especially when it comes to sushi, I would avoid anything without a top rating," says Sana Mujahid, PhD, manager of food safety and testing at CR.

How and where you buy seafood, as well as how you handle and prepare it, matter if you’re to reduce the risk of food poisoning from bacteria and other pathogens. Follow these tips to make sure you buy the freshest catch and store it properly.

• Know the signs of spoilage. Seafood is more perishable than meat or poultry, so check before you buy. Fish should smell mild and clean, not fishy or sour. Fillets shouldn't be discolored or dry around the edges, and flesh should be firm and springy. For whole fish, look for clear, shiny eyes.

• Don't dismiss frozen fish. Unless you live near a fishing community, the fish you buy likely hasn't come off the boat that day. Fish needs to be transported, and the quality can degrade during travel. Freezing fish right when it's caught helps maintain flavor and moisture. So frozen fish may actually be a higher-quality product than fresh. Frozen fish can also be less expensive and, because it minimizes food waste, better for the environment. When shopping for frozen seafood, avoid packages with frost or ice crystals, which may mean the fish has been stored a long time or thawed and refrozen.

• Shop clean. Keep seafood separated from other foods in your shopping cart and shopping bags, so bacteria that could be on the fish don't spread to other foods. Pick up seafood last, and store it in a clean cooler with ice if you can't get it into your refrigerator within 2 hours—1 hour if the temperature outdoors is over 90° F.

• Store it right. Once you get home, keep raw seafood well-wrapped or in a sealed container in your refrigerator to ensure that drips don't contaminate other foods. It's probably best to store raw seafood in the main area of the fridge. The door isn't meant for perishables, and temperatures are more likely to fluctuate in bins than in your refrigerator's main compartment.

• Use it or freeze it. Freeze raw seafood you won't use within one to two days. Lean fish keeps for six to eight months in the freezer; fatty fish such as salmon, two to three months. However, what looks like fresh fish may sometimes have been previously frozen and thawed at the store, so if there's no sign saying so, ask at the fish counter. If you’ve bought previously frozen fish, don't refreeze: The flavor and texture will suffer.

• Thaw slowly. To thaw, place the frozen fish in its bag or its wrapping on a plate in the refrigerator. In a hurry? Place fish in cold water in a sealed plastic bag.

• Prep right. Make sure your work area is clean before you start, and use a separate cutting board and utensils for seafood, then clean them with hot, soapy water. Afterward, use hot, soapy water and paper towels to clean up, especially if there are spills.

• Check for doneness. That means making sure the fish reaches an internal temperature of 145° F. Checking with an instant-read food thermometer, preferably a digital one, is the most precise method. For thicker fish such as a salmon steak, slip the thermometer into a side of the fillet. But because it's hard to use a thermometer on shellfish or a delicate fillet of sole, the Department of Agriculture says it's also okay to check for doneness by cooking fish until the flesh is opaque and separates or flakes easily with a fork. Cook crabs, lobster, and shrimp until the flesh is opaque and pearly; clams, mussels, and oysters, until their shells open; scallops, until they are milky white or firm and opaque.

• Be temperature-wise when serving. Refrigerate cooked seafood within an hour or two. For seafood served cold, as in a shrimp cocktail or salad, keep it refrigerated until you’re ready to eat it. For picnics or buffets, place the serving dish in a bowl or tray of ice.

• Throw it out if you’re not sure it's okay. If you don't know—or can't trust—how your seafood was stored before cooking, how it was prepared, or how it was maintained after cooking, play it safe and throw it away. That's better than taking the chance of a foodborne illness, says CR's Mujahid. Toss leftover cooked seafood after two days in the fridge.

One of the most important food safety steps you can take is to use a good food thermometer to make sure your seafood, meat, and poultry are cooked to the proper temperature.

Editor's Note: This article also appeared in the July 2023 issue of Consumer Reports magazine.

Lauren Kirchner

Lauren Kirchner is an investigative reporter on the special projects team at Consumer Reports. She has been with CR since 2022, covering product safety. She has previously reported on algorithmic bias, criminal justice, and housing for the Markup and ProPublica, and was a finalist for the Pulitzer Prize in Explanatory Reporting in 2017. Send her tips at [email protected] and follow her on Twitter @lkirchner.

Althea Chang-Cook

Althea Chang-Cook is the associate director of content at Consumer Reports, covering food and kitchen gear, as well as stories for diverse audiences. She also edits many of CR's Outside the Labs evaluations and a wide variety of other content. Prior to joining CR in 2018, Althea covered food, health, parenting, product safety, technology, and more for various publications.