A Fish Story Not to Ignore
Thread carefully when it comes to the catch of the day
Because fish are basically swimming filters, they soak up pesticides, industrial waste, and chemicals that have been dumped into waterways for decades. With more polluted waters than ever, the risk is rising that you’ll find a contaminated fish on your dinner plate. Salmonella and scombriod poisoning, which is caused by a histamine produced by bacteria on fish, can also make certain fish unsavory.
Part of the reason that inedible fish are ending up in the grocery store is that there’s no government-run process to inspect fish. In fact, fish and shellfish are the only major sources of protein that do not receive comprehensive government inspections for potential contamination. The $9 billion industry is overseen by a piecemeal system led by the Food and Drug Administration, whose inspectors visit processing plants an average of once very four years.
In a 1991 report issued by the National Academy of Sciences, current safety regulations were deemed “insufficient” and “too limited in frequency and direction to ensure enhanced safety of seafood.” While some efforts to improve seafood handling have been made since then, substantial problems remain.
Freshwater fish are more likely contain toxic chemicals than fish that spend their lives in the ocean. Because of industrial dumping and air pollution, the Great Lakes have been found to be swimming with polychlorinated biphenyls (PCB), which are suspected of raising the risk of cancer and birth defects. Residues of DDT, the cancercausing pesticide banned decades ago, have been found in Great Lakes whitefish being sold in southern California.
Fish that live in deep, offshore waters, such as cod and haddock, are considered low in chemicals because the areas they live in aren’t easily contaminated. But chemicals can be found in saltwater fish that live close to polluted urban shores, or in fish that commute to freshwater. Puget Sound, the Chesapeale Bay, and Santa Monica Bay are all considered risky sources, according to the National Academy of Sciences.
Among ocean-swimming fish, fin fish from tropical or subtropical areas have the most problems. Barracuda, grouper, amerjack, and certain tropical snappers have been linked to scombrod as well as ciguatera – a sometimes-severe disease that affects the nervous system and can cause vomiting and nausea. Nether bacteria is destroyed in the cooking process.
Methyl mercury poisoning from swordfish is a great enough risk that the National Academy of Sciences recommended that couples who intend to have children in the near future should avoid the fish. Tuna and Mahi-mahi can also contain methyl mercury in small amounts, but the danger in swordfish is much greater.
The riskiest seafood of all is molluskan shellfish such ad oysters, clams, and mussels. The intestines and internal organs of these mollusks are fertile ground for contaminants. The problem is worsened by fishermen who illegally harvest shellfish in polluted waters. Many mollusks get contaminated because they live where rivers and seas meet and, because of nearby cities, these waters often are contaminated.
Oysters, clams, and mussels are also vulnerable to Norwalk viruses, which can cause sever diarrhea unless the shellffish is fully cooked. Another source of contamination is the algae called “Red Tides.” The FDA and the coastal states all test for these blooms, and when they appear the waters are closed to all fishing.
Even oysters taken from clean waters occasionally harbor a naturally occurring, unfriendly bacteria known as Viro vulnificus, according to reports from the National Centers for Disease Control and Prevention. It contaminated mollusks are eaten raw and the bacteria remains alive, it can make a person very sick. Healthy people will probably just get a bout of indigestion. But for those with their liver ailments and depressed immune systems, Viro vulnificus can be deadly. Symptoms can include sudden chills, indigestion, fever, nausea, vomiting, and stomach pain.
So what is safe? According to the National Academy of Science report, catfish, trout, salmon, and other formed species are generally reliable as long as they are cooked immediately before serving. Processed fish, such as fish sticks and fish nuggets are also safe bets because they are made from white-fleshed fish, such as cod, haddock, and pollack. And canned tuna is not only the safest of all seafood, but it is also the most popular.
No matter what the fish, there are some simple precautions you can take when shopping for and storing seafood, though. Here are some tips from Get Hooked in Seafood safety, which is published by the U.S. Food and Drug Administration.
Select seafood with a fresh, mild odor: It should not smell unpleasantly fishy. Fish fillets should be moist, without any traces of browning or drying around the ages.
Check the gills, scales, and eyes: The gills should be bright pink or red. And the eyes should be bright and clear, not cloudy or sunken. Scales should cling tightly to the skin, and they should be slimy.
Mollusks in the shell should be alive when you buy them. When a clam, oyster, scallop or mussel is alive, its shell is tightly closed or closes when it is lightly tapped.
Test shellfish for freshness. Hold the shell between your thumb and forefinger and depress it, as though sliding two parts of the shell across one another. If the shell moves, the shellfish is not fresh. Throw away any mollusks whose shells aren’t closed tightly.
Unless you freeze it, cook fish within two days of purchase. Smoked fish, pickled fish, and vacuum-packed fish should always be refrigerated. Whatever the fish, keep it its original wrapper and store in the coldest part of your refrigerator, which is usually under the freezer or in the meat drawer, until it is ready to be cooked.
If you did freeze it, allow one day to thaw. Thaw frozen seafood in its own container in the refrigerator. Do not thaw seafood at room temperature or under warm running water.
Store mollusks live. Keep mollusks in your refrigerator in a container covered loosely with a clean damp cloth. Do not store live shellfish in an airtight container or in water.
A Taster’s Guide to Ordering Fish: Consult this list and you’ll never need to ask the waiter again to describe the fish entries. If you’re cooking at home, you can substitute one fish from the same list for another in a recipe.
Very light, delicate: Cod, Dover sole, Haddock, Lake Whitefish, Orange Roughy, Pacific Halibut, Pacific Sanddab, Southern Flounder, Witch Flounder, Yellowtail Flounder, Yellowtail Snapper.
Light to moderate: Butterfish, Catfish, Cobia, English Sole, Mahi Mahi, Pacific Whiting, Red Snapper, White Sea Trout, Rock Sole, Snook, White King Salmon, White Sea Trout, Whiting, Winter Flounder.
Very light, delicate: Alaska Pollock, Brook Trout, Giant Sea Bass, Grouper, Pacific Ocean Perch, Rainbow Trout, Smelt, Walleye, White Crappie, White Sea Bass.
Light to moderate: Atlantic Ocean Perch, Atlantic Salmon, Black Drum, Carp, Chum Salmon, Croaker, Jewfish, King Salmon (Chinook), Lake Herring, Lake Sturgeon, Lake Trout, Monkfish, Mullet, Northern Pike, Perch, Pink Salmon, Pollock, Sand Shark, Stripod Bass, Swordfish.
Pronounced Flavor: Atlantic Mackerel, Spanish Mackerel.
Light to moderate: Black Seabass, Bluefish, Sockeye (Red) Salmon, Tuna.
How to Clean a Fish
- Scale: Wash first, cut off pectoral fins.
- Draw: Cut from vent to head, remove entrails.
- To remove head: Cut above the collarbone and snap the spine. Cut tail where it joins the body.
- Remove the dorsal fin bones: Cut along length of each side. Remove connected bones with a quick pull toward the head.
- Filleting: Begin slice behind the collarbone just beyond the gill. With the knife flat against the backbone, cut with a sliding motion to the tail.
- Skinning: Begin Cut about 1/2 inch from the tail. With the knife held flat against the skin, slice toward the head end.
Illustration: Megan Jorgensen
Ones that can get away
The National Academy of Sciences report, Seafood Safety, judged the following seafood to be unsafe at times: Amerjack, barracuda, raw clams, the pasty mustard in crabs, finfish from subtropical waters, finfish from tropical waters, grouper, green-colored tomalley in lobsters, mahi-mahi, salmon caught in the Great Lakes, Shelfish (especially raw oyesters, mussels, scallops).