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Before you bite: Facts on fish, chicken, beef

"Today" food editor Phil Lempert responds to your questions about food safety, labeling,  storage and more

This week, we answer just a few of the over 2,300 e-mail questions that we received from our popular "5 Things You Need to Know" series which focused on poultry, fish and meat.

Q: Is it true that Chilean sea bass is not a bass at all, but a member of the cod or pollock families? Why is it relatively so expensive? (Jeff M., Suffern, NY)

Correct. It is not a bass. It's a toothfish.

Patagonian Toothfish (Dissostichus eleginoides) is sold under the trade names Chilean sea bass in the USA, Merluza Negra in Argentina and Uruguay and mero in Japan. It is not a cod, bass or pollock but a toothfish. Sometimes its cousin, the Antarctic toothfish, is sold under the name Chilean Sea Bass as well.

Many factors play into expense
This fish is expensive because it is long-lived (it lives about 45 years), slow-growing (it takes 10 years to mature), limited in geography (it's found only in the cold southern waters off the Antarctic) and there is a great demand for the firm, dense, slightly oily, clean sweet taste, melt-in-your mouth texture, and it is a very forgiving fish which is perfect for different styles of preparation. This creates a very lucrative pricing; thus the name "white gold" given to it by the fishing industry. This convergence of factors (a tasty fish, a profitable fish to catch, a population limited by biology, and geography) naturally encourages over fishing.

Q: What is the maximum time you can keep frozen fish? Frozen shrimp? Also what is the best method to defrost frozen shrimp? (Larry, Springfield IL)

The USDA (U.S. Department of Agriculture) Center for Food Safety and Applied Nutrition says lean frozen fish can be kept for six months, fatty frozen fish for 2-3 months, and frozen shrimp for 3-6 months.

Frozen fish, once bought from the supermarkets, should be brought home immediately and stored in the home freezer at zero degree or lower. The fish should not be taken out of its original sealed packages.

The FDA (Food and Drug Administration) says, "Don't thaw meat and other frozen foods at room temperature. Instead, move them from the freezer to the refrigerator for a day or two; or defrost in the fridge. You can also defrost in the microwave oven or during the cooking process, but texture and flavor might be damaged. And be sure to cook immediately."

Nothing will save a piece of fish if the package's air tight seal is lost. Those important omega-3 fats found in fish are highly unstable and quickly oxidize once exposed to air. You can recognize oxidation from the rancid, "fishy" smell and taste that accompanies it.

Tip: To freeze seafood at home, start with high quality fish. Fish should be cleaned first under cold water and then patted dry. Wrap with plastic wrap, excluding as much air as possible. Then over wrap your fish with freezer paper or aluminum foil. (There are also specially designed plastic bags for use in the freezer). Carefully seal all packages and label with contents, amount, and date. Place package in the coldest part of the freezer and where the cold air can circulate around them, freezing them quickly. Shellfish such as shucked clams, oysters, or mussels can be frozen in rigid air-tight plastic containers. Refreezing shrimp under non-commercial conditions can significantly affect the flavor and textures, and, in some cases, may make the shrimp, when thawed, unsafe to eat.

Q: Is there a difference in the levels of Omega-3s in wild salmon vs. farm-raised salmon? (Christine W.)

Yes, wild has more.

FDA statistics on the nutritional content (protein and fat-ratios) of farm versus wild salmon show that:

The fat content of farmed salmon is excessively high - 30-35% by weight.

Wild salmon have a 20% higher protein content and a 20% lower fat content than farm-raised salmon. Farm-raised fish contain much higher amounts of pro-inflammatory omega-6 fats than wild fish.

These unfortunate statistics are confirmed in a recent (1988-1990) study conducted by the USDA to compare the nutrient profiles of the leading species of wild and cultivated fish and shellfish. Three species of fish that contain beneficial omega-3 fats were included: catfish, rainbow trout, and coho salmon.

Q: I want to purchase only US beef. How can the USDA packaging go on beef from another country? Why isn't the package marked from what country the beef is produced and who in our government is allowing this? (Scott M., Wampsville, NY)

You are correct that USDA packaging can appear on beef imported from another country, therefore it is possible that the beef did not originate in the United States. All that the USDA seal means is that the product meets U.S. food safety standards (regardless of what country it comes from).

In response to the second part of your question, there are proposals in the working that MIGHT (and hopefully in my opinion!) require Country of Origin Labeling (COOL). In 2004, labeling for fish and shellfish took effect affecting retailers with gross sales larger than $230,000. COOL regulations for meat however was postponed.

Right now COOL labeling is expected to take effect on September 30, 2008 (although Congress might change this), but there is no final labeling guideline set yet. 

Q: Can you explain the term aged beef? (W. Cary L., Little Rock, AR)

Most often used to refer to dry aging (not wet) in a controlled, refrigerated environment which results in water evaporation and enzymatic activity which concentrates the flavor of the beef.

Aging beef is an ancient practice that surely began out of necessity — drying (or smoking) meat was the only way to preserve it in pre-refrigeration days, although people no doubt realized early on that it could improve flavor and texture.

Directly after cattle are slaughtered, their meat is generally quite tender, which is one reason people like fresh-killed meat. During the first 12 to 24 hours postmortem the meat will toughen as the muscle fibers shorten due to rigor mortis. After that, however, enzymes in the meat attack the structural proteins that make meat tough (a process called "postmortem proteolysis"), resulting in slow and natural tenderization. The process happens quickest in pork and lamb and generally slowest in beef.

Enzyme action has the additional effect of improving and strengthening the flavor of the beef, due to the breakdown of proteins into amino acids. Since aging would normally allow bacteria and mold to act on the beef, it's carried out at low temperatures, generally between 34 and 38 degrees F. Beef can be aged anywhere from a few days to as long as six weeks, with the average probably being around 10-14 days.

The more marbling (or fat) in the beef, the better it ages, since fat helps retain moisture and flavor in the beef. Therefore, fattier cuts of beef, such as sirloin and prime beef, are ideal for aging.

Aging is typically done by the so-called dry method, where the beef is hung in a freezer for a prescribed time prior to cutting. Dry aging results in a loss of meat over time due to water evaporation and surface mold (which must be trimmed off), but is said to concentrate the flavor of the meat.

An alternative method is wet aging, where the meat is stored in large vacuum bags that seal the moisture in and keep some of the mold out. Wet aging reduces the loss of meat due to evaporation and mold, resulting in more saleable meat, but generally doesn't develop an agreeably strong taste to the degree that dry aging does.

Q: How long is cooked chicken safe for in the fridge? (Jerry C., Eldorado, IL)

Whole chicken is safe for three days while cut-up chicken is safe for two days. Cooked chicken should not be left at room temperature for more than two hours. A whole cooked chicken can be kept in the refrigerator for three days and cut-up cooked chicken can be stored in the refrigerator for two days.

Phil Lempert is food editor of the “Today” show. He welcomes questions and comments, which can be sent to or by using the mail box below. For more about the latest trends on the supermarket shelves, visit Phil’s Web site at .

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