(Editor's Note: This article as adapted from a review of seafood safety prepared by the U.S. Department of Agriculture's Center for Food Safety and Applied Nutrition.
Fish and shellfish are an important part of a healthful diet. They contain high quality protein and other essential nutrients . . . can be low in saturated fat . . . and may contain omega-3 fatty acids. In fact, a well-balanced diet that includes a variety of fish and shellfish can contribute to heart health and children's growth and development.
But, as with any type of food, it's important to handle seafood safely in order to reduce the risk of foodborne illness. Follow these basic food safety tips for buying, preparing, and storing fish and shellfish - and you and your family can safely enjoy the fine taste and good nutrition of seafood.
Special Health Notes
If you are pregnant, nursing your child, or thinking about becoming pregnant, it is important that you avoid consuming too much methylmercury. This substance can be found in certain fish, and it can harm an unborn child's developing nervous system if eaten regularly.
Don't Eat . . .
Avoid these four fish species:
However, don't deny yourself or your unborn baby the nutritional benefits of fish - you can eat 12 ounces (2 average meals) a week of other types of cooked fish, as long as you eat a variety of kinds that are lower in mercury. This same advice should be followed when you're feeding fish and shellfish to your young child, but serve smaller portions.
Do Eat . . .
Five of the most commonly eaten fish that are low in mercury are:
Another commonly-eaten fish, albacore ("White") tuna, has more mercury than canned light tuna. So, when choosing your two meals of fish and shellfish, you may eat up to 6 ounces (one average meal) of albacore tuna per week.
"Local Catch" Alert
Be sure to check local advisories about the safety of fish caught by family and friends in your local lakes, rivers, and coastal areas.
Buying from a retailer who follows proper food handling practices helps assure that the seafood you buy is safe - and helps maintain the quality of the seafood too. Be sure to check out a market's seafood counter carefully to see whether the seller is practicing proper food handling techniques. Ask yourself: What is my general impression of this facility? Does it look and smell clean?Fresh Fish: How To Choose It
To be sure the safety of seafood is being properly preserved, only buy fish that is refrigerated or properly iced. Fish should be displayed on a thick bed of fresh ice that is not melting, and preferably in a case or under some type of cover.
Fish should smell fresh and mild, not fishy, sour, or ammonia-like. A fish's eyes should be clear and bulge a little (except for a few naturally cloudy-eyed fish types, such as walleye pike). Whole fish and filets should have firm, shiny flesh and bright red gills free from slime. Dull flesh could mean the fish is old. Note: Fish fillets that have been previously frozen may have lost some of their shine, but they are fine to eat. The flesh should spring back when pressed. Fish fillets should display no darkening or drying around the edges. They should have no green or yellowish discoloration, and should not appear dry or mushy in any areas.
Why Freshness Counts
Healthwise, it is important to look for freshness when choosing seafood. In some species, if the catch has been left out in the sun too long - or the fish haven't been transported under proper refrigeration - toxins known as scombrotoxin, or histamine, can develop. Eating spoiled fish that have high levels of these toxins can cause illness.Frozen Fish: Know What To Look For
Today, fresh catches can be processed and frozen immediately to very low temperatures - frequently, this takes place right on the fishing vessel. However, frozen seafood can spoil if the fish thaws during transport and is left at warm temperatures for too long.
To help ensure that the frozen fish you're buying is safe, follow these guidelines:
Selecting Shellfish: Some Special Guidelines
The Food and Drug Administration requires shellfish harvesters and processors of oysters, clams and mussels to put a tag on sacks or containers of live shellfish (in the shell), and a label on containers or packages of shucked shellfish.Tags and labels contain specific information about the product, including a certification number for the processor, which means that the shellfish were harvested and processed in accordance with national shellfish safety controls. Ask to see the tag or check the label when purchasing shellfish.
In addition, follow these general guidelines:
Storing Seafood: Keep It Safe Until You Eat It
Put seafood on ice or in the refrigerator or freezer soon after buying it, using these guidelines for safe storage:
When You Catch Your Own: Tips for Staying Safe
Thaw frozen seafood gradually by placing it in the refrigerator overnight. If you have to thaw seafood quickly, either seal it in a plastic bag and immerse it in cold water, or - if the food will be cooked immediately thereafter - microwave it on the "defrost" setting and stop the defrost cycle while the fish is still icy but pliable.Prevent Cross-Contamination
When you're preparing fresh or thawed seafood, it's important to prevent bacteria from the raw seafood from spreading to ready-to-eat food. Take these steps to avoid cross-contamination between raw and cooked foods:
Cook It Properly
Most seafood should be cooked to an internal temperature of 145 °F. But if you don't have a food thermometer, there are other ways to determine whether seafood is done.
Serving Seafood: Don't Cross-Contaminate
Cross-contamination can happen once your seafood is cooked, too. Here are simple ways to keep your seafood safe when serving:
Picnic Tip: A Clean Cooler Is Critical
Be sure to clean coolers with hot soapy water before packing cooked seafood. Cleaning is especially important if the cooler was previously used to transport raw seafood. A clean cooler prevents harmful bacteria from the raw fish from contaminating cooked seafood or other foods.Temperature Counts
Follow these serving guidelines once your seafood is cooked and ready to be enjoyed.
Eating Raw Seafood: What You Need To Know
It's always best to cook seafood thoroughly to minimize the risk of foodborne illness. However, if you choose to eat raw fish anyway, one rule of thumb is to eat fish that has been previously frozen.Some species of fish can contain parasites, and freezing will kill any parasites that may be present. However, be aware that freezing doesn't kill all harmful microorganisms. That's why the safest route is to cook your seafood.
An Important Note About Oysters: Some oysters are treated for safety after they are harvested. That information may or may not be on the label. However, these oysters should still not be eaten raw by people at risk for foodborne illness. The post-harvest treatment eliminates some naturally occurring pathogens, but it does not remove all pathogens that can cause illness.Special Health Notes
Keep in mind that some people are at greater risk for foodborne illness, and should not eat raw or partially cooked fish or shellfish. These susceptible groups include:
Pregnant women, older adults, and people with weakened immune systems have an increased chance of getting a foodborne illness called listeriosis. If you are in one of these groups, there is a simple step you can take to reduce your chance of contracting the listeriosis disease from seafood:
Avoid refrigerated types of smoked seafood except in a cooked recipe, such as a casserole. Refrigerated smoked seafood, such as salmon, trout, whitefish, cod, tuna, or mackerel, is usually labeled as "nova-style," "lox," "kippered," "smoked," or "jerky" and can be found in the refrigerated section of grocery stores and delicatessens. They should be avoided. You needn't worry about getting listeriosis from canned or shelf-stable smoked seafood.
By following the basic food safety tips for buying, preparing, and storing fish and shellfish you and your family can safely enjoy the fine taste and good nutrition of seafood.