The Maryland Department of Environment continually updates it's fish consumption health advisory charts, the last one being in 2007. Much of this seems to be politically driven, the agency claiming at one time that commercially caught fish were perfectly safe to eat, while those caught by hook and line were not. WHAT? This, of course, was sheer lunacy, and I suspect the statement was made to the press in a futile attempt to protect, and possibly bolster, Maryland's failing seafood industry.
If you carefully examine the charts, most species have been contaminated with either PCBs or mercury, both of which are lethal. And, from my experience working in the medical field for nearly 15 years, there is no safe level of PCB or mercury. Even in tiny amounts, spaced over a wide time frame, both are toxic to every form of life. And, from what I've read, mercury is a cumulative toxin that the body cannot rid itself of. It is so toxic that when a school nurse accidentally breaks a thermometer the school is usually shut down until a hazmat team comes and clears any remnants of mercury from the area. Now, that may be a bit of overkill on the part of the school system, but what idiot at the Maryland Department of Environment, Health Department, FDA, etc... decided that we can safely consume mercury and PCBs embedded in our food supplies?
If you want seafood, go for the farm raised variety--it's much fresher, and much safer to consume. Here are a few guidelines for selecting seafood that I wrote about several years ago that may be helpful:
1. Use the "sniff test." Smell the fish, crab meat, etc... If it smells fishy, it has spoiled, or in the process of spoiling. And, there's a good chance it's loaded with bacteria.
2. Firmness. If the product, particularly fish fillets, are firm, this is a good indication it is relatively fresh. The term "relatively" essentially means it was caught with two days, properly iced down or flash frozen, and shipped iced or frozen to the retailer within a day of reaching the wholesaler.
3. Local (home grown) does not translate to fresh. The sniff test will prevail here.
4. Toxins. Oily species of fish tend to contain the most toxins. Bluefish, tuna, king mackerel (kingfish), billfish, weakfish, etc... are on the list of those containing the highest levels of mercury. Striped bass, flounder, black sea bass, shark, spiny dogfish, perch and most freshwater species usually contain less mercury and PCBs, but they still have relatively high levels in the fatty tissue just beneath the skin, and the dark tissue along the lateral lines. Blue crab contains high levels of toxins in the hepata-pancreas (mustard).
5. Remove the skin and rinse thoroughly. With many species, particularly those that are somewhat oily, removing the skin and thoroughly rinsing the fillets in cold, fresh, running water will decrease the amount of toxins by a significant degree. You CANNOT get rid of ALL the mercury and PSBs because some of it is embedded in the meat itself, but removing as much as possible will help to some degree.
6. Preparation. All forms of seafood should be thoroughly cooked. Granted, there are Sushi Bars and Raw Bars that serve raw seafood, claiming "No one ever got sick eating at my restaurant." Yeah, right--I still believe in the tooth fairy, too! Consuming raw seafood is foolish, especially in this day and age when the water quality where that animal was caught is considered highly toxic or bacteria laden. This includes all of Chesapeake Bay and it's tributaries, and for the most part, every major body of water in the U.S., Europe, South America, and Asia.
7. Farm raised is safer. Most aquaculture operations must meet rigorous health standards and are inspected regularly. This is true of both finfish and shellfish. In many instances, the water flowing in raceways is filtered to minimize contamination of the product. Shellfish, such as oysters and clams are usually raised on floating platforms so they are not subjected to the toxins found in the body of water's bottom sediment. When harvested, the process is very quick, efficient and in most instances the product is cleaned, washed thoroughly and flash frozen. With the exception of shrimp, shellfish, are usually iced down and shipped live. Farm raised shrimp, also called zebra and banded shrimp, are harvested, beheaded, cleaned, washed and flash frozen, then usually shipped the same day. It's rare that farm-raised shrimp fail the sniff test.
8. Eat small portions. The days of consuming huge quantities of seafood are over.
Eat Mo Chicken!