sábado, 14 de mayo de 2011

Seafood Safety

Get live crab!

Our first installment of informational posts:

Real and Imaginary Concerns
News reports talk more about the dangers, then the benefits of eating seafood. Should you be afraid to eat fish? In a word, NO! Your health has much more to gain from eating fish, especially fatty species, such as: Salmon, Herring, Mackeral, Sardines and Rainbow Trout, then by avoiding seafood. In fact, people who eat seafood regularly are healthier than those who do not. But there are some potential dangers and it is good to know about them.
Real healthy concerns come from eating fish and shellfish that carry bacteria, viruses or toxins that cause illness. Like other foods, spoiled fish can make you ill, so it is important to refrigerate seafood right after you buy it, at a temperature as close to 32 F degrees as possible. Eat fish as soon as you can, after you buy it. Keep frozen seafood as cold as possible, and avoid storing it for too long. This is because freezers change temperatures often and fish quality declines.
Imaginary dangers are those that could occur under unusual circumstances, but are not generally a problem in the U.S. An example of this potential health risk from PCBs and dioxins. These contaminants are found only in extremely small amounts and are publicized in the news.

Will Seafood make you ill?
Most fish in the marketplace is completely safe to eat. However, certain species and some fish from tropical waters can be riskier than others. Not all fish or shellfish have substances that cause illness and not everyone who eats fish with disease causing agents will become ill. That is because disease organisms vary in their ability to cause illness. People, too, differ in their susceptibility to harmful substances. People who are most likely to become ill include: elderly people, pregnant women and young children, and those with impaired immune systems (e.g., those with HIV\AIDS, liver disease, diabetes, cancer, gastrointestinal disorders, and people taking steroids, chemotherapy, or immune suppressant drugs).
The greatest danger comes from eating raw or partially cooked mollusks (snails, oysters, mussels, clams, octopus and squid). Not all mollusks are contaminated, but there is no way to tell if they are. Because the diseases linked to raw shellfish are serious, the safest practice is to avoid eating raw shellfish. However, states producing shellfish must abide by strict limits on bacteria count, so illness from eating raw shellfish has become less common.
Harmful viruses are almost always linked to shellfish harvested from waters contaminated with sewage. The two most common are Norwalk virus and hepatitis A. Norwalk virus causes gastrointestinal upset, but symptoms usually subside after 48 hours. Hepatitis may not be detected for 2-6 weeks and can be long-lasting and severe. Hepatitis A virus can survive light cooking, so simply steaming shellfish until the shells open may not destroy all the virus, if it is present.
Bacteria mostly occur in shellfish but can be present in some ready to eat fish products. Cooking destroys most bacteria, so again, the danger lies mainly with raw shellfish. The family bacteria known as “Vibrios” can cause serious illness, especially in people with compromised immune systems. Illness from ready to eat seafood occurs only rarely.
Besides viruses and bacteria, some fish-mainly species from tropical or subtropical waters- may have toxins that cause illness. The two most common types are ciguatoxin and scombrotoxin, or histamine poisoning. Ciguatoxin is found mainly in reef fish such as barracuda, grouper, and snapper. There is no way to tell whether a particular fish contains the toxin and not all fish caught in the same area will have the toxin.
The other toxin, histamine, is associated mainly with mahi mahi, fresh tuna, mackerel and bluefish. The toxin develops when fish have not been kept sufficiently cold after harvesting and shipping. Symptoms of illness develop quickly after eating the affected fish, but usually disappear within 24 hours.

The Safest Seafood
Canned fish and shellfish are the safest forms of seafood because they are cooked and have been tightly sealed. They are suitable for people of all ages and health conditions.
Seafood Storage: Store all fish and shellfish in the refrigerator or freezer. Live shellfish should have ventilated containers. Do not store live shellfish in water. Use as quickly as possible and discard all dead animals (shells do not open after cooking) and any with broken shells. Live crabs, lobster and crayfish move their legs. Do not cook or eat any dead shellfish.
Raw seafood to be cooked: When preparing raw seafood at home, first wash your hands with soap and hot water. Then, be sure that no cutting board, wrap, utensils, or containers used for raw seafood come into contact with cooked item. Viruses and bacteria can easily transfer to the cooked food and provide an opportunity for the illness. Thoroughly scrub all materials that touched raw seafood.
Frozen Seafood: Thaw frozen seafood in the refrigerator or under cold running water. Do not thaw at room temperature or in warm water. Doing so will enable bacteria to grow. When possible, cook frozen fish and shellfish directly in the frozen state.
Raw, marinated, and smoked seafood: Use only commercially frozen shellfish and fish to prepare sushi, gravlox, ceviche, or at home smoked seafood. This will eliminate any possible parasites that may be in the fish. Use only shellfish obtained from reputable stores and has come from certified shellfish growing waters. Fish stores should have the certification tags on display. Raw, marinated, or partly cooked can be safe for healthy people, but may not be so for people with compromised immune systems. Pregnant women are taking unnecessary health risks eating these seafoods during pregnancy.
Environmental Contaminants
Mercury is a contaminant found in small amounts in all fish and shellfish. Too much mercury can be risky for pregnant women and young children. They should avoid eating species with high mercury levels—shark, swordfish, king mackerel and tilefish. Eating a variety of species reduces the chance of getting too much mercury. Fortunately, recent analysis showed that Alaskan salmon, cod andpollock have among the lowest levels of mercury of all seafoods. Mackerel, herring and sardines are also low in mercury. Everyone can eat these fish without worrying about safety. Organic contaminants such as PCBs, dioxins and pesticide residues are generally found only in very low amounts in most fish sold commercially. Current consumption of these contaminants from commercially available fish and shellfish has not been linked to any health risks. Experts agree: the health benefits from eating fish far outweigh any risks.

Written by Joyce A. Nettleton, DSc, RD, ScienceVoice Consulting, Denver, CO
Obtained from: Alaska Seafood.org

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