Urban myths die hard, especially now that we have e-mail to keep them alive and running.
Perhaps that’s why the one about microwave ovens leaching dioxin out of plastic containers and, thereby, causing cancer keeps coming back around.
Or perhaps it’s because sometimes the latest scientific study contradicts an earlier one, and even if plastic food containers did not contain dioxin – much less cause cancer – two years ago, it doesn’t mean that’s still the case.
It’s probably because when it comes to our children, we can never be too careful.
Several readers have asked about the latest cooking-with-plastics rumor, which warns people against putting plastic baby bottles and other containers, including plastic-wrapped TV dinners and those printed paper cartons containing Ramen noodle soup in the microwave, as well as putting plastic water bottles in the freezer overnight. (I suppose these could be especially dangerous if defrosted in the microwave).
At various times over the past 10 years, studies “proving” there is a problem have been attributed to the Johns Hopkins School of Public Health, the Walter Reed Army Medical Center and some doctor in Hawaii.
“It’s a hoax that’s been going around for years and years,” says Jessica Sippel, public affairs officer at Johns Hopkins. “We still get inquiries weekly. It just keeps going around.”
It hasn’t changed
The truth, as of now, is still the same, Sippel says: Plastic containers do not contain any dioxin. However, plastics, especially plastic wraps, do contain chemical “plasticizers” to make them less brittle and more flexible, and these chemicals can be released into food or beverages when they are heated up. The absorption rate of these chemicals, which act as synthetic hormones and can cause health problems for susceptible populations, including growing children, depends on the temperature and duration of heating, the type of plastic used and the food heated. (Fatty foods absorb more.)
The general rule, according to Rolf Halden, assistant professor of environmental health sciences at Johns Hopkins, is that plastic containers, wraps, bags and utensils are safe as long as they are used only for their intended purposes, according to directions on the containers. In other words, we should read directions and not put any containers in a microwave that don’t specify that they are microwave-safe.
Also, we should microwave food in packaging materials only if the package directs, and never use the same packaging over again. To minimize exposure to any chemicals in plastics as much as possible, use inert containers, such as heat-resistant glass and ceramics in microwaves and ovens and stainless steel on stove tops, Halden advised in an online Q&A interview with the Johns Hopkins Office of Communications and Public Affairs.
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