INTERNATIONAL FOOD SAFETY CONSULTANCY
DR WILLEM MARSMAN
To get the best value for your money when buying seafood, it’s important to know what you’re buying. Be wary of unusual bargains – some seafood is seasonal. If there is a considerable difference between the price of a fresh product and what you are accustomed to paying, it could be that it is from the last season’s frozen inventory. Buy from a reputable dealer. And if the fish you choose looks or smells different from what you expect, discuss it with the fish market manager.
Look for firm, shiny flesh that bounces back when touched. If the head is on, the eyes should be clear and bulge, and the gills should be bright red. The fish should not smell “fishy” – it should smell like a fresh ocean breeze.
It’s easy to miss the telltale signs of species substitution. Sometimes, taste or consistency is the only way to detect it. If you feel you have purchased something different from what was represented, tell your fish market manager.
Here’s how to distinguish some common species:
Haddock has a dark lateral line along the skin surface.
Skinless cod fillets have a distinctive white papery membrane along the belly and a white line of fat along the lateral line of the fillet.
Shark and swordfish look alike, but shark has a dark streak of flesh in the centre and rough skin along the edge.
Red Snapper comes only from the Atlantic Ocean and the Gulf of Mexico (ask your retailer where the snapper originated).
Orange Roughy comes only from Australia and New Zealand and always arrives frozen. It may be sold thawed, but it must be labelled as previously frozen.
Scrod is not a type of fish. The term originated in the Boston area to describe the catch of the day. It is a fish under two and a half pounds that is either cod, haddock or Pollock. Such fish should be labelled in the market or listed in a restaurant as “scrod cod”, “scrod haddock”, or scrod Pollock”.
Buy only from reputable sources. Be wary, for example, of vendors selling fish out of the back of their pick-up trucks.
Buy only fresh seafood that is refrigerated or properly iced.
Don’t buy cooked seafood, such as shrimp, crabs or smoked fish, if displayed in the same case as raw fish. Cross-contamination can occur.
Don’t buy frozen seafood if the packages are open, torn or crushed on the edges. Avoid packages that are above the frost line in the store’s freezer. If the package cover is transparent, look for signs of frost or ice crystals. This could mean that the fish has either been stored for a long time or thawed and refrozen.
Put seafood on ice, in the refrigerator or in the freezer, immediately after buying it.
Recreational fishers who plan to eat their catch should follow state and local government advisories about fishing areas and eating fish from certain areas.
Anyone who’s ever smelled rotting seafood at the fish counter has a pretty good idea of what a poorly run seafood market smells like. But the absence of any strong odour doesn’t necessarily mean that the seller is practicing safe food handling techniques.
Based on FDA’s Food Code, here are some points to consider:
Employees should be in clean clothing but no outerwear and wearing hair coverings.
They shouldn’t be smoking, eating, or playing with their hair. They shouldn’t be sick or have any open wounds.
Employees should be wearing disposable gloves when handling food and change gloves after doing nonfood tasks and after handling any raw seafood.
Fish should be displayed on a thick bed of fresh, not melting ice, preferably in a case or under some type of cover. Fish should be arranged with the bellies down so that the melting ice drains away from the fish, thus reducing the chances of spoilage.
What’s your general impression of the facility? Does it look clean? Smell clean? Is it free of flies and bugs? A well-maintained facility can indicate the vendor is following good sanitation practices.
Is the seafood employee knowledgeable about different types of seafood? Can he or she tell you how old the products are and explain why their seafood is fresh? If they can’t, you should take your business elsewhere.
The fish’s eyes should be clear and bulge a little. Only a few fish, such as walleye, have naturally cloudy eyes.
Whole fish and fillets should have firm and shiny flesh. Dull flesh may mean the fish is old. Fresh whole fish also should have bright red gills free from slime.
If the flesh doesn’t spring back when pressed, the fish isn’t fresh.
There should be no darkening around the edges of the fish or brown or yellowish discoloration.
The fish should smell fresh and mild, not fishy or ammonia like.
Generally, seafood is very safe to eat, but raw or undercooked seafood can be unsafe.
Seafood grown or collected from contaminated water can get colonized by viruses in the water. Shellfish foods, such as oysters, pump a lot of water through their bodies each day and filter out micro-organisms. Thus, they are very likely to collect viruses from the water. Some oysters, for example, are eaten raw or lightly cooked, which increases the risk of foodborne illness. And viruses are not the only culprits. Bacteria and parasites are threats to raw seafood, as well. To keep seafood safe:
Buy only fresh seafood that is refrigerated or properly iced.
Always cook fish thoroughly. Cooking fish until it’s opaque and flaky helps destroy any existing pathogenic bacteria that may be present.
All consumers should avoid eating raw oysters or shellfish. People with liver disorder or weakened immune systems are especially at risk for getting sick.
Seafood can be an important part of a balanced diet for pregnant women. It is a good source of high quality protein and other nutrients and is low in fat.
However, some fish contain high levels of a form of mercury call methylmercury that can harm an unborn child’s developing nervous system if eaten regularly. By being informed about methylmercury and knowing the kinds of fish that are safe to eat, you can prevent any harm to your unborn child and still enjoy the health benefits of eating seafood.
Mercury occurs naturally in the environment and it can also be released into the air through industrial pollution. Mercury falls from the air and can get into surface water, accumulating in streams and oceans. Bacteria in the water cause chemical changes that transform mercury into methylmercury that can be toxic. Fish absorb methylmercury from water as they feed on aquatic organisms.
Nearly all fish contain trace amounts of methylmercury, which are not harmful to humans. However, long-lived, larger fish that feed on other fish accumulate the highest levels of methylmercury and pose the greatest risk to people who eat them regularly. You can protect your unborn child by not eating these large fish that can contain high levels of methylmercury:
While it is true that the primary danger from methylmercury in fish is to the developing nervous system of the unborn child, it is prudent for nursing mothers and young children not to eat these fish as well.
Yes. As long as you select a variety of other kinds of fish you are pregnant or may become pregnant, you can safely enjoy eating them as part of a healthful diet. You can safely eat 12 ounces per week of cooked fish. A typical serving size of fish is from 3 to 6 ounces. Of course, if your serving sizes are smaller, you can eat fish more frequently. You can choose shellfish, canned fish, smaller ocean fish or farm-raised fish – just pick a variety of different species.
There is no harm in eating more than 12 ounces of fish in one week as long as you don’t do it on a regular basis. One week’s consumption does not change the level of methylmercury in the body much at all. If you eat a lot of fish one week, you can cut back the next week or two and be just fine. Just make sure you average 12 ounces of fish a week.
Some kinds of fish are known to have much lower than average levels of methylmercury and can be safely eaten more frequently and in larger amounts. Contact your federal, state, or local health department or other appropriate food safety authority for specific consumption recommendations about fish caught or sold in your local area.
There can be a risk of contamination from mercury in fresh waters from either natural or industrial causes that would make the fish unsafe for you or your family to eat. The Environmental Protection Agency provides current advice on fish consumption from fresh water lakes and streams. Also check with your local health department to see if there are special advisories on fish caught from waters in your local area.