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plugin-Berkeley_irradiation - Update on irradiation Many...

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Unformatted text preview: Update on irradiation Many people shrink from the idea of eating irradiated food. Irradiation—that is, treating foods (especially meats) with forms of gamma rays, electron beams, or X-rays#is a way to kill disease-causing bacteria, parasites, and other pathogens in order to make foods safer. Every year in this country an estimated 76 million people get food poisoning and, of these, 325,000 have to be hospitalized and 5,200 die. Outbreaks of food poisoning might largely become a thing of the past if irradiation were widely used. The Wellness Letter, while acknowledging that irradiation would have some benefits, has always emphasized the downside: the proliferation of radioactive material in processing plants, the exposure of workers, and the chance that irradiation would be seen as a substitute for cleanliness and good handling. But technology has made some strides, and the U.S. govern- ment has approved a large number of foods for irradiation. The World Health Organization,American Medical Association, Cen- ters for Disease Control, and American Dietetic Association all say that foods can be safely irradiated and consumed. Other coun- tries irradiate many kinds of foods. A few irradiated foods are already in our supermarkets. It's time for a new look at irradiation. How are foods irradiated? Three technologies exist. The oldest is the use of gamma rays from a radioactive substance such as cobalt 60 or cesium 137—a technology long used in medical facilities around the world. The second is electron beams (e~beams}—-a stream of electrons emit- ted from an electron gun (something like the device that lights up a TV tube). E-beams, like gamma rays, are already used for sterilizing medical instruments. The third and latest method is quite familiarmX-ray irradiation—but is still under develOpi-nent for processing foods. The machine is similar to a dental X—ray machine, but more powerful. All these are cold processes, and do not raise food temperature. Right now e-bearn radiation is used most commonly. Does irradiation melt the packaging anwor cause harmful chemicals to leach into the food? No, or at least it should not. Some packaging materials have already been approved for irradiated foods. But if irradiation is ever widely adopted, more materials will need to be tested. Irradiation should ideally take place after the food is put into its final packaging. What are the specific benefits? Many disease—causing germs are reduced or eliminated. Treating raw meat and poultry at the slaughter plant could eliminate bacteria such as E. coil, Salmonella, and Campylobacter. It could kill Listeria in ready-to—cat meats and sausages. It could eliminate parasites and bacteria from fresh produce. Also, it kills insect pests on food. It makes foods last longer—for instance, irradiated strawberries will keep two or three weeks in the refrigerator. So then could I stop worrying about hygiene? Not at all. Foods can become contaminated after irradiation if they are not handled properly. Irradiated foods are still subject to spoilage. You’d still need to cook poultry thoroughly. But if you cooked beef rare, it would be less of a risk (though not risk-free). Are irradiated foods radioactive? Will they harm me? irradiated foods are not radioactive, any more than your suitcase is radioactive after it goes through X-ray screening at an airport. Food does not touch any radioactive material—gamma rays, 4 UCBerkdqy WelhwsLefla; W2003 D Livy-.1:wa .. ____. . e—bearns, and X—rays penetrate foods without producing radio- activity. No adverse effects have showu up in people eating irradiated foods. Astronauts have done well on irradiated food, but there’s not much long-term evidence. Animals fed irradiated food for generations have suffered no ill effects. Still, some experts remain unconvinced. Are there foods that cannot be irradiated? Lettuce and other leafy vegetables turn mushy. Shellfish, particu— larly oysters, will decrease in quality after irradiation. Eggs in the shell can turn milky and unappetizing. Which foods are most suitable? Meat, fish, fruits, many vegetables, poultry, and grains. Ground meat and sausage—highly susceptible to spoilage—are probably the best candidates. Are any irradiated foods in American stores? Some strawberries from Florida and some tropical fruits from Hawaii are irradiated. As of January 2003 some irradiated ground beef has appeared in supermarkets and chain restaurants. It may also start appearing in school lunches. Herbs and spices are routinely irradiated to kill microorganisms. Since 1963 the FDA has approved a number of foods for irradiation, including wheat flour, white potatoes, pork, poultry, and meats. But few manufac- turers have started. Irradiated foods are supposed to be so labeled, except in cases where only a minor ingredient, such as a spice, has undergone irradiation. Restaurants in this country and elsewhere are not required to label or otherwise identify irradiated foods. Does irradiation harm nutrients? So far as is known—and there is hardly any controversy about this—the nutritional value of irradiated foods is unchanged, or at least no more changed than by any other kind of processing, including cooking. The B vitamin thiamine may be slightly reduced. Changes are so small that it’s hard to tell afterward whether a food has been irradiated or not. Apart from the excep— tions listed above, foods generally retain their taste and texture. Are processing plants dangerous? Do they generate waste? Cobalt 60 has to be made in a nuclear reactor, and cesium 13? is a by-product of nuclear fuel processing. It’s possible that some accident could occur in transporting them to processing plants, but the radioactive materials are sealed in canisters designed to resist almost any force without breaking. Cobalt 60 does eventu- ally have to be disposed of, but since it comes in solid metal form, it will not spread throughout the environment. It is not a highly ‘ problematic waste‘."""~' Medical facilities using cobalt 60, such as bone marrow transplant centers, have operated for more than 30 years without a fatal accident. There have been a few incidents of leakage and contamination, requiring costly cleanups, but none exposed the public to radioactivity. Cesium 13? can dissolve in water and thus could spread through the environment. Such an accident occurred at a medical facility in Georgia, but with out serious consequences. Cesium rods are now being manufactured in a ceramic that cannot dissolve. They last a long time, and do not need to be transported on a regular basis. E-beam and X-ray facilities produce no waste and do not contain or produce radioactive substances. All radiation stops when the machines are turned off. What about protecting workers at the plants and those transporting the materials? The federal government, and several of its agencies (such as the Department of Transportation and the Nuclear Regulatory Com— mission) enforce stringent rules for the transport of radioactive materials. So far no difficulties have occurred in transport to medical facilities here or around the world. In the case of e-beam or X~ray facilities, nothing has to be transported. Workers at medical and food—processing facilities are protect- ed by federal and state agencies, including the Occupational Safety and Health Administration. They have to be shielded from e- bearns and X-rays. The FDA oversees and inspects such facilities. Is irradiation just like pasteurization? Some people say so, but that’s misleading. Both processes kill harmful bacteria. But pasteurized foods are heated convention- ally, not irradiated. Could there be ‘fineltdowns” at food-processing facilities or terrorist attacks? Meltdowns are impossible since the plants contain no nuclear reactors. Cobalt 60 and cesium 137 could not overheat or explode. Hospitals all over the country use the same kind of technology (for radiation treatments and sterilization of wastes) as that used in food-processing plants, and no terrorist attacks have ever taken place against them. A terrorist might steal radioactive materials from such a facility, though, to use in making a bomb.“ E—beam and X-ray machines would neither melt down nor pro- voke terrorist attacks. So should we give irradiated foods a big welcome? A cautious “hello” would be more like it. Irradiation involves some trade-offs. In the case of meat and meat products that spoil easily, irradiation could prevent at least some of the illness, suf— fering, and deaths caused by food-borne pathogens. It could be a boon in developing countries where refrigeration, and sometimes food, is scarce. On the Other hand, zapping food cannot be a sub- stitute for cleanliness and proper handling in industry, the market— place, and the home. Some experts point oat that we don’t really know for sure whether eating irradiated food is safe in the long term, but so far there’s no evidence of any dangers to consumers— while the dangers of food poisoning are clear. We do think that irradiated foods should be so labeled. That way, you can avoid them if you choose. Is there a cancer personality? We’ve learned a great deal about cancer, but it’s still hard to explain why some people get cancer and others do not. One much- disputed theory is the “cancer-prone" personality—a notion first proposed by the tobacco industry to take the heat off cigarettes. According to this idea, pessimistic, hostile, or even naive people are inclined to get the disease. (Usually the reasoning is back— wards: such-and-such a person has canolar; it must be her bad attitude that did it.) We’ve always had our doubts about this, and two good recent studies have strongly challenged the notion. Japanese researchers, reporting in the Journal ofthe National Cancer Institute in June, studied 30,000 people, whom they classified by personality type. Over the years no connection between personality and canoer risk could be observed. Another study, from Finland and pub- lished in the International Journal ofConcer. found that person— ality had “no important effect” on breast cancer risk. The study involved more than 12,000 women and was begun in 1975. This does not mean that cancer happens at random, or that you have no control whatever over whether you get it. The Japanese researchers pointed out, not surprisingly, that there was a cause- and—effect relationship between smoking and lung cancer, and between excessive alcohol consumption and several kinds of cancer. Maybe personality has something to do with poor habits, such as smoking or excessive drinking. Thus, in some ways, attitude can influence cancer risk. Opti- mism and a strong desire to stay well are valuable assets in life. If you are healthy, a hopeful attitude can motivate you to stick to a healthy diet, refrain from tobacco use, drink alcohol moderately (if you drink at all), avoid sunburn and suntanning, and go for needed tests and checkups (breast exams and mammogram, prostate exams, colon cancer tests, skin exams, and the like) that may prevent cancer or catch it early. It’s still true-wand most of us can cite examplee—that people who lead very healthy lives get cancer. But not because of bad personality traits. The Japanese researchers did find that people already diag- nosed with cantfier were more likely to be anxious and emotionally unstable than healthy people. This is understandable, but is sure— ly not to be blamed on personality. Many people with cancer benefit from support groups and psychological counseling. Opti- mism and a courageous spirit can be an advantage, not only in following a course of treatment, but in living well after a cancer diagnosis. Badmouthing fillings Some health issues never seem to go away, and mercury in the amalgams used for filling dental cavities is one of them. These fillings are mixtures of copper, silver, tin, and sometimes zinc; mercury is added to harden the mix. Some people claim these fillings are toxic and a long-term health risk, causing everything from insomnia to multiple sclerosis. There are movements afoot to ban them, and plenty of people to assure you that they are dangerous and ought to be removed. Here are the facts: I Dental amalgam does indeed contain mercury, and very small amounts of it may be released when you chew or when the tooth is drilled. But there is no evidence that these amounts are toxic, or that they cause disease or disability or other harm (except for rare allergic reactions). There are literally hundreds of studies to back up this statement. I Scores of experts and government organizations have cer- tified that these fillings are safe. Nevertheless, the National Institutesof Healthgnd other agencies support ongoing studies. ' Health Canada advises, just to be on the safe side, that people with impaired kidneys should not get mercury amalgam fillings, and advises pregnant women not to have such fillings removed (since that may release more mercury) and not to get new ones. I The U.S. Centers for Disease Control and Prevention sees little or no evidence of harm from amalgams, and nothing to be gained by removing such fillings. The American Dental Associa~ lion discourages people from having their fillings removed~it’s expensive, and you risk tooth damage. And keep in mind: Many young people today have no cavities, and those who have cavities have fewer ofthem. Thus, amalgam use is declining. Moreover, other substances are coming into use for fillings. One ofihese days, {free all keep brushing and flossing, drinking fluoridated water, and getting regular checkups and cleanings, fillings in teeth—and the controversy—may pass into history. UC Berkeley Wetfizers Letter, Emitter 2005 5 ...
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This note was uploaded on 02/17/2011 for the course FOOD SCI 201 taught by Professor Horowitz during the Spring '10 term at Wisconsin.

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plugin-Berkeley_irradiation - Update on irradiation Many...

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