Fish on ice at a market.

Whether it's grilled salmon, peel-it-yourself shrimp, or a festive clambake, fish and shellfish are often the star of summer meals. But how do you make sure you're serving up seafood that's safe to eat, keeping the chance of foodborne illness to a minimum?

Fish and shellfish are a common cause of foodborne illness. In fact, they were responsible for 28 percent of reported outbreaks in the U.S. in 2015, according to the latest data from the Centers for Disease Control and Prevention.

Taking the right storage, cooking, and serving steps can significantly slash your risk of foodborne illness. Here's what experts advise to help you ensure that you're serving safe seafood.

Seafood and Foodborne Illness

Like many foods, seafood may carry pathogens that can make you sick, including bacteria such as salmonella and vibrio vulnificus, and occasionally viruses.

More on Food Safety

"In my opinion, seafood is unique because some of it, like oysters, is eaten raw, and other seafood is not cooked with as much heat and time as you would cook a steak, for instance," says James E. Rogers, Ph.D., director of food safety research and testing at Consumer Reports.

Because cooking can kill off bacteria, this most often happens when fish and shellfish are raw or undercooked, or kept in danger-zone temperatures (between 135° F and 41° F) that allow these potentially harmful substances to grow.  

It can also occur when bacteria or viruses are transferred from seafood to people via improperly cleaned cutting boards, plates, and knives, for example.

(Some pathogens, such as listeria, can live in properly stored refrigerated items like smoked fish or seafood salad, so keep an eye out for recalls. And salmonella and noroviruses may thrive in cooked foods that have been contaminated by someone with one of these illnesses, so keep anyone who is ill away from food prep.)

For most people, a bout with foodborne illness is unpleasant but short term, causing symptoms that range from mild stomach upset to cramping, diarrhea, and vomiting.

“If you have a healthy immune system, it might just be an uncomfortable 24 hours,” says Lauri Wright, Ph.D., R.D.N., an assistant professor of nutrition and dietetics at the University of North Florida in Jacksonville and a spokeswoman for the Academy of Nutrition and Dietetics. “But for young children, older adults, and people whose immune system is compromised by health problems such as diabetes or liver disease, it could lead to hospitalization or even in rare cases, to death.”

A photo of crab legs; store them right to make sure you're serving safe seafood.

8 Ways to Prevent Foodborne Illness

Shop smart. For safe seafood, keep fish and shellfish (as well as eggs, meat, and poultry) separated from other foods in your shopping cart and shopping bags. Pick up seafood last, and store it in a clean cooler with ice if you can’t get it into your home refrigerator within 2 hours—1 hour if the temperature outdoors is over 90° F. (Find tips on how to choose seafood that's less likely to be contaminated with pollutants like mercury here.)

Store it safely. Once you get home, the USDA recommends keeping raw seafood well-wrapped or in a sealed container in your refrigerator to ensure that drips don't contaminate other foods. (Do the same with meat and poultry.)

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 any raw seafood you won’t use within one to two days. Lean fish will keep for six to eight months in the freezer, fatty fish such as salmon for two to three months. To thaw, place the frozen fish in its bag or wrapping on a plate in the refrigerator.

In a hurry? For safe seafood, thaw frozen fish and shellfish under cold running water in a sealed plastic bag, then cook it right afterward, says Katrina Levine, M.P.H., a registered dietitian and an extension associate in food safety and nutrition at North Carolina State University in Raleigh.

Prep properly. "Make sure your work area is clean before you start," Rogers says, "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 the area, especially if there are spills." 

Cook it right. As mentioned earlier, an internal temperature of 145° F is considered safe for seafood, and should significantly reduce the chance of foodborne illness, Rogers says. Checking with an instant-read food thermometer, preferably a digital one, is the most precise method.

For thicker fish such as a salmon steak, you can slip the thermometer into a side of the fillet, Levine says. But because it's almost impossible to use a thermometer on shellfish or a delicate fillet of sole, the USDA notes that it's also considered safe to cook 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; and scallops until they are milky white or firm and opaque.

Be temperature-wise when serving. Cook seafood to an internal temperature of 145° F. For thicker fish, such as a salmon steak, slip an instant-read food thermometer (preferably a digital one) into a side of the fillet.

For shellfish or a delicate fillet of sole, the Department of Agriculture says it’s also safe to cook it until the flesh is opaque and 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; and scallops until they’re milky white or firm and opaque.

Refrigerate cooked seafood dishes within an hour or two of serving. If you’re serving seafood 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 of ice so the fish stays cool, Wright suggests.

Reconsider raw fish. In addition to sushi, this includes ceviche, seafood marinated in lemon or lime juice long enough for acids to turn the flesh white. “It looks cooked, but it really isn’t,” Wright says. Raw clams and oysters can carry vibrio vulnificus, which in some cases can be deadly.

According to the Food and Drug Administration, avoiding fish from polluted waters is not a guarantee that you won’t get sick. Neither is abiding by the common misconception about avoiding raw shellfish in months that don’t contain the letter “r.” And contrary to common belief, hot sauce and alcohol do not kill bacteria that cause foodborne illness.

When in doubt, throw it out. "If you do not know—or cannot trust—how your seafood has been stored before cooking, prepared, or maintained after cooking, it is better to dispose of it rather than take the chance of a foodborne illness," Rogers says. "Seafood can be pricey, but getting sick can be as well." Toss leftover cooked seafood after two days in the fridge.