Fish and Seafood Guide
For years the American diet has been more turf than surf, partly due to concerns about safety. But experts say that with a few smart strategies, you can enjoy today's catch without fear—and reel in some amazing health perks to boot.
Juicy boiled lobster. Succulent grilled salmon. Fresh shrimp cocktail. Seafood dishes like these are practically synonymous with summer. If you're like most folks, however, you're not putting much on your plate.
The average American consumes only about 4.8 ounces of seafood a week, according to the NOAA Fisheries Service. That's 40 percent short of the 8-ounce weekly minimum recommended by the latest dietary guidelines. Sure, some people just aren't crazy about fish. But many more avoid it out of worry.
Although finfish and shellfish sold in the U.S. are some of the safest in the world, news about environmental contaminants such as mercury (which is harmful to young and unborn children) and PCBs (which research has linked to cancer in certain doses) can make seafood seem downright scary. Digestive woes are another concern: Seafood is a leading cause of food-borne illness. Yet the bigger danger, health experts say, is allowing fear to overshadow seafood's perks.
Tips for Buying Fresh Fish
Tally your recent intake. Some types of seafood tend to be higher in mercury and PCBs than others. By controlling your exposure over time, you can enjoy the health benefits of eating fish without facing harm. See "How many servings are safe?" (below) for details.
Stop and sniff. If the fish department in your local supermarket smells like ammonia or has an overwhelmingly, well, fishy odor, the offerings might be past their prime. Although the bacteria responsible for food spoilage generally do not make people sick, certain types of finfish— including tuna, anchovies, mackerel, and mahi mahi—can cause an illness known as scombroid poisoning if eaten when spoiled, resulting in digestive upset, nausea, and an allergy-like reaction.
Bottom line: From a freshness and safety standpoint, fish should have a pleasingly briny scent—closer to an ocean breeze than low tide. Take a gander at the gills. If you're buying a whole fish, ask the counter person to show you its gills before wrapping it up. A bright red color indicates the fish is fresh, Santerre says. On the other hand, a dull brick or brown hue means the fish has begun to spoil. Other signs of freshness include intact scales and clear (not cloudy) eyes. If you're buying a fillet, look for firm flesh that springs back to shape after being pressed.
Don't fear fish from troubled regions. Last year's BP oil spill left tons of crude and chemical dispersants in the Gulf of Mexico, while this spring's catastrophic earthquake and tsunami in Japan sent radioactive water streaming into the Pacific. Is seafood harvested from nearby areas safe? Representatives from the FDA say yes because fish from these regions is closely scrutinized and tested before it's allowed into the food supply. Santerre agrees. "From a radiation standpoint, I have absolutely no concern about Japanese seafood products in our markets or restaurants," he says. Likewise, ongoing tests of Gulf seafood conducted by federal regulators have uncovered no signs of harmful contamination thus far. If you're still concerned, however, it's easy to choose fish from other areas.
Tips for Prepping Fresh Fish
Refrain from freezing. Some supermarket fish sold as "fresh" actually was flash-frozen for transport, then thawed for display in the seafood case. One round of freezing generally isn't a problem in terms of taste or safety, but freezing the fish again could compromise it.
"Ice crystals that form during a second freeze can puncture the cell walls of fish and make it mushy," Santerre says. "This also increases the risk of bacterial growth." Because it's not always easy to tell whether fish was previously frozen, your best bet is to cook it no more than two days after purchase—even if you can't eat it all at once. Leftovers will keep in the fridge for about three days.
Trim the fat. PCBs accumulate in an animal's fatty tissue, so trimming skin and visible fat from a fish prior to cooking is an easy way to reduce your exposure, Santerre says. Lower your risk even more by grilling or baking fish on a metal rack so remaining fat drips away. (Just resist the
urge to use those drippings in sauces.)
Take its temperature. Food safety experts generally recommend cooking fish until its center reaches 145°F, the point at which most illnesscausing bacteria and parasites are killed. "The flesh should be opaque and flake easily with a fork," Morgan says. But what to do about fish that are traditionally served rare in the center, such as tuna and salmon? If you don't like them well done, consider buying frozen. Many pathogenic bacteria and parasites are destroyed by freezing temperatures.
Buying Fresh Shellfish
Select shiny shrimp. Raw shrimp should be firm and glossy, with translucent flesh that has uniform color. The thin dark "vein" (really the digestive tract) that runs along a shrimp's outer curve is safe to consume, Santerre says. But because it can taste gritty and comes with a certain ick factor, most people opt to buy deveined shrimp or devein them at home using a paring knife or special plastic tool.
Look for a lively lobster. Lobsters and crabs spoil quickly after death—even if they're kept in cold saltwater. So choose a crustacean with moving legs and upright claws, Morgan advises. And when the fishmonger pulls your pick from the tank, its appendages should squirm or contract. (The shell color is not important—all lobsters turn red when cooked.)
Choose oysters from chilly waters. You may have heard that it's especially dangerous to eat uncooked oysters in months that lack an "R"—May through August. Not necessarily true. This advice might have originated in the days before refrigeration, when bacterial contamination was more common. That said, if you're planning to eat oysters raw (although certain groups of people, such as pregnant women and people who are immunocompromised, shouldn't), be choosy about their origins.
Those from warm waters are more likely to harbor Vibrio vulnificus, a bacterial strain that causes a handful of deaths every year, according to the FDA. Play it safe and pick bivalves from colder locales, such as the North Atlantic Ocean, instead. You may also wish to choose oysters labeled "post-harvest processed" (or PHP), which means they've been treated with a method such as pressurization to kill bacteria, including V. vulnificus.
Shake shells shut. Though stores don't display them in water tanks,
whole fresh mollusks such as clams, mussels, and oysters should be alive at the time of purchase. Two signs of life to look for: tightly closed shells, or shells that shut when tapped or when the mollusks are gently jostled in a bag. Reject any that stay open or have shells that are cracked.
How to Prepare Shellfish
Let mollusks breathe. Supermarkets often place live clams, mussels, and oysters in disposable plastic bags to minimize cross contamination with other groceries on the way home. Eventually, however, the lack of air can suffocate them, speeding bacterial growth. Transfer shellfish to an open bowl or netted bag, then refrigerate until
you're ready to cook or eat. Don't put live shellfish directly on ice unless
it's serving time—as fresh water melts, it can kill them.
Give shrimp a soak. Once you get home, you might notice that the fresh shrimp you purchased has a faint iodine scent. This comes from the plankton the animals fed on and is not dangerous, Morgan says. Soaking the shrimp in a bowl of cold water for 15 minutes before cooking can reduce the iodine odor and aftertaste.
Boil in small batches. If you plan to steam or boil live clams, mussels, or oysters, use a small pot and allow them a bit of elbowroom. If shellfish are overcrowded, those in the center might fail to cook completely,
according to the FDA. Don't st op when shells open. From a taste standpoint, clams, mussels, and oysters generally are considered done when their shells open. To ensure they reach a safe internal temperature, cook them for a few minutes longer. (Toss any that stay closed, a possible sign of spoilage.) Shrimp and scallops are done when their flesh is firm and opaque. The same goes for lobsters—check the meat on the underside of the tail.
Tips for Frozen Fish and Shellfish
Pass on icy packages. If you see frost or ice crystals clinging to the fish (or if the bag is opaque and you can hear ice chips rattle when you shake it), look for another package. This is a sign that the fish has been in deep freeze for too long or that it has been thawed and refrozen, both of which raise the risk of food-borne illness.
Go from freezer to fridge. Thawing fish at room temperature is risky because bacteria can multiply in the food before it softens enough to cook. Instead, place the fish in a cool environment, which allows it to thaw while keeping harmful microbes in check. Two safe options: Stick the fish in the fridge overnight, or seal it in a plastic bag and immerse it in cold water, changing the water every 30 minutes until the fish becomes flexible. Need a shortcut? Microwave on the lowest defrost setting until the fish is pliable but still cool. And no matter what your preferred thawing method, cook the fish promptly once it is soft. Raw fish should not be refrozen.
How Many Servings of Fish are Safe?
In general, the bigger a fish and the longer its life span, the higher its concentration of industrial pollutants such as mercury and PCBs. That's because aquatic creatures absorb these chemicals from the environment and pass them up the food chain as they're preyed upon by other fish.
By taking steps to limit your exposure, however, the health benefits of seafood far outweigh the risks. Here's an informal guide on how often to eat the most popular types.
Understand Labels on Seafood
Some supermarkets trump up their seafood descriptions with buzzwords that can make the offerings sound better than they really are. The truth behind three of the most common might surprise you.
Organic: Despite years of wrangling, this label is not backed by the USDA for use on seafood. With other animal products, "organic" partly means the animal was raised on organic feed. That's tough to verify with wild fish, which have uncontrolled diets, and with predatory species such as tuna, which consume other (potentially nonorganic) fish. Seafood that is certified organic in other countries can be sold in most U.S. states, but there's no guarantee of what you're getting.
Dayboat: This term is used to communicate freshness and cleanliness—it means the seafood was caught and ferried to shore
within one day. The catch? Unless you live right near the water, it can take up to two weeks for that fish to reach your local market.
Wild-caught: This indicates the fish was not raised in an aqua farm, an important distinction for salmon. Farm-raised varieties often contain synthetic dyes and are lower in omega-3s than their wild-caught counterparts. Just be aware that this label is sometimes abused: Several years ago, a small Consumer Reports investigation revealed that nearly 57 percent of "wild" salmon samples purchased in supermarkets actually were farm-raised. To ensure your selection is really wild, choose
salmon from Alaska, where salmon farming is banned. (Alaska supplies the majority of wild salmon in the U.S., and it's most abundant in summer.)
Tips for Dining Out Safely
Unless you're a health inspector, you probably don't get to see inside
many restaurant kitchens. Don't fear the unknown. Just follow these two simple safety pointers from registered dietitian Molly Morgan.
Go raw in the right place. For fish that's served uncooked or rare—such as sushi and pan-seared tuna—there's little room for error in storage and prep. That's why Morgan says it's best to order such dishes at specialty seafood restaurants only. "Their chefs are more familiar with the steps needed to prepare these meals safely," she says—such as deepfreezing the fish first to kill infectious bacteria and parasites. Morgan adds that cooked fish and shellfish are generally fine to order at any reputable restaurant.
Determine the delivery date. You may have heard the advice to never order fish on a Monday. There's some truth to that. Many restaurants—especially those in areas far from coastal waters—do not receive seafood deliveries between Saturday and Tuesday, so the start-of-the-week special might have a greater chance of making you sick. That said, delivery schedules vary. Your server can tell you whether your selection was received that day.
"Seafood is an excellent source of lean protein, is relatively low in calories, and is rich in iron, zinc, and vitamins A, D, and B12," says Molly Morgan, a registered dietitian in Vestal, New York.
Many types of fish, including salmon, sardines, and mackerel, are rich in omega-3 fatty acids, which are associated with a reduced risk of heart attack, stroke, depression, and memory problems. "You can safely enjoy fish and shellfish," assures Charles Santerre, Ph.D., a seafood safety expert and professor of food toxicology at Purdue University in West Lafayette, Indiana. "All you have to do is take the right precautions."
With the following guide, your next meal is sure to go swimmingly.
How Much Fish is Safe?
Up to 3 a Month
- Chilean sea bass
- Striped bass
- Ahi, bigeye,
canned albacore tuna
- Orange roughy
- King mackerel
Up to 6 a Month
- Mahi mahi
- Black bass
- Freshwater trout
- Atlantic mackerel
- Skipjack tuna