When microwaves were first introduced as rather expensive kitchen novelties, they engendered fear more than anything else. In some circles, they were even labeled miniature nuclear reactors. Since then, the U.S. Food and Drug Administration has developed strict standards to regulate microwaves, which now must be leakproof and equipped with safety systems that turn the oven off when the door is opened.
How microwaves work
Microwaves themselves are a form of electromagnetism, not unlike X-rays, light rays and radio waves. However, they radiate at a lower frequency than X-rays and, in fact, are closer in that respect to FM radio waves. They cook foods quickly because the food absorbs the microwaves directly, while glass, paper and plastic containers allow them to pass right through. (In conventional cooking, heat is applied from the outside and gradually makes its way into the food after it thoroughly heats up the container).
Microwaves cook by causing water molecules inside food to vibrate, thus creating the heat to do the cooking. In this way, microwaving is a kind of steaming, which, as we all know, is one of the best ways to preserve nutrients.
Microwave cooking safety
Over the years, two groups of microwavers have emerged: those who will use microwave ovens only for reheating or defrosting foods, and those who have developed an entire repertoire around the specialized techniques that microwaves require.
There are dozens of good microwaving cookbooks available. However, the results are often more complicated and less satisfying than using conventional cooking methods. The Internet, which is the single most efficient way developed to spread rumors, has been full of stories about plastic wraps and plastic dishes that leak chemicals into microwaved food, which causes cancer and a myriad other health problems. According to the FDA, "It's true that substances used to make plastics can leach into food, but as part of the approval process, the FDA considers the amount of a substance expected to migrate into food and the toxicological concerns about the particular chemical." Under federal provisions, new substances used to make plastics for use in cooking are classified as "food contact substances" and must be found safe for their intended use. They further state that they have "assessed the migration levels of substances added to regulated plastics and has found the levels to be well within the margin of safety based on information available to the agency." Nonetheless, there's no reason not to be a little cautious. The substance in plastic wraps that are of such concern are the very ones that make the wraps clingy and flexible. None of the wraps on the market that have been approved for microwave use contain plasticizers.
If you want to make sure that the wrap you're using is one of those, look for wraps made of polyethylene; they should say "microwave safe." Try not to touch the food with the wrap. You can "tent" it by leaving extra space or using toothpicks to hold it up away from the food. You can safely used waxed or parchment paper or just plain paper towels. Before you defrost foods in the microwave, remove the plastic wrap. When you are microwaving in a plastic container, make sure it is labeled "microwave safe." This means that the plastic is inert and no chemicals will migrate. It also means the container is strong enough to withstand the heat of the microwave. Even more worrisome than potentially migrating chemicals is that non-approved containers -- margarine tubs, carry-out containers from restaurants and very thin plastic bowls -- can warp. You risk getting burned when you remove them from the microwave. The trays that come with frozen dinners are only meant to be used once and should be discarded after you heat the food packaged in them. You should also avoid using plastic storage bags, grocery bags, newspapers or aluminum foil in the microwave. Tips for microwave cookingTo maximize the usefulness of your microwave, especially for fruits and vegetables, add as little water as possible. A teaspoonful is usually plenty to keep the food from burning; there should be no water left at the end of the cooking process.
It is better to defrost frozen fruits and vegetables in the microwave than at room temperature because they will lose fewer nutrients. Cooking at high power when possible will reduce the cooking time and also help to retain more nutrients. In order to avoid overcooking, let the foods stand for a minute or two to finish the cooking process. Be sure to keep the inside of your microwave clean since spatters can absorb microwave energy and increase cooking time. If you catch the spatters quickly, they are easy to wipe it out with a damp cloth or a sponge. Don't ever use abrasive cleansers. If spills get dried on, try boiling a cup of water in the microwave and wait for the steam to soften up the mess. Then wipe it out. Sheldon Margen, M.D., is a professor of public health at the University of California at Berkeley. Dale A. Ogar is managing editor of the University of California at Berkeley "Wellness Letter."
Source: Health & Wellness
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