Whirrrrrrr ... There's been another spin on the wheel of mealtime roulette.
Eating fish is riskier than we once thought. According to Consumers Union, publishers of Consumer Reports magazine, 113 samples of seafood from 40 stores around Chicago and New York showed contamination, mislabeling and traces of bacteria.
(If you missed earlier headlines: One-third of all samples were mislabeled, generally as higher-priced varieties; eight out of 20 samples of swordfish measured more than legal levels of mercury, which can lead to birth defects; 50 fish samples carried traces of fecal coliform bacteria, which can lead to food poisoning, and 34 of the samples were just plain spoiled.)
If you're one of the millions of Americans who's trying to include more of this nutritious, low-fat and high-protein food in your diet, you're stuck sniffing at a stone-cold wad of something sealed in plastic. It's nearly impossible to check for the common signs of freshness.
But knowing how fish goes bad may help you make better selections.
Seafood is one of the most perishable forms of protein. With its delicate cell structure and absence of most connective tissue, both shell and fin fish decomposes quickly. Mishandle it and the odds for problems increase.
* Odor sets in. When held too long, either in transit or storage, the natural enzymes and fluids in seafood begin to break down. (According to Consumer Reports, spoilage creates a compound called trimethylamine.) The first result is that the normally light, briny fragrance of freshly caught fish rapidly becomes, well, fishy.
* Fluid builds up in the package. As the tissue settles and the cell walls collapse, the meat releases liquid. These juices are even more fragile than the flesh itself. They not only sour and heighten the foul smell, but the loss of juices lead to dry or mealy texture when the fish is cooked.
* Discoloration occurs. Species vary, but the meat of most fish tends to range from a pale, light color to a bright, vibrant hue. The older the harvested fish, the more apt it is for white flesh to yellow, and for red-meat fish to darken.
* Translucence, a natural feature of fish, is lost. Older fish are apt to take on a surface appearance that looks glazed and, eventually, sticky.
The three previous signals of poor-quality fish are largely matters of aesthetics. But they also can alert the shopper that illness may be the outcome of making a bad choice at the seafood counter.
Food poisoning can take many forms. Fecal coliform bacteria is the biggest villain. This potential source of foodborne illness turned up in nearly half of the East Coast and Midwestern fish studied by Consumers Union. Such bacteria can lead to the classic signs of food poisoning and, at worst, may prove fatal to ill, very young or aged individuals.
While bacteria can frequently be found on shellfish taken from waters tainted by raw sewage, fin fish normally are unaffected. Proper handling, however, is the wild card. Bacteria becomes a problem when the catch is held too long under unsafe conditions.
One of the biggest variables -- and one that's out of the hands of consumers and retailers -- is how things are handled offshore. Fishing crews sometimes stay out longer than normal in order to capitalize on bountiful catches -- or wait out poor ones. Thus, anything caught early may be stored days longer than what is normally safe.
Worse, some older or ill-equipped vessels may lack adequate cooling facilities. In some cases, fish stay on deck for hours while crews scoop up more. Exposed to air and sun, the fish die and begin to decompose. If the fish has been gutted and dressed, then stored improperly, the bacteria found naturally in their intestines may spill and multiply on the fillets.
Storage temperatures are always a concern, not only aboard ship but in the supermarket and at home. Thirty to 32 degrees is considered ideal; home refrigerators normally range closer to 40 to 45 degrees.
Assuming you've purchased seafood from a reputable source (one that participates in the voluntary U.S. Department of Commerce seafood-inspection program, has a rapid turnover of stock and then handles the product properly) the normal temperature range of your refrigerator shouldn't jeopardize your health -- if you:
* Quickly transport the food from store to home fridge, with no stops en route to pick up dry cleaning, etc.;
* Refrigerate and use up the fish within 24 hours;
* Follow sanitary practices at home; and
* Cook the fish thoroughly before serving it.