Your Health Matters
By Claudia Parks, R.N.

Plastics and the Microwave: Stories about the dangers of chemicals leaching from plastic into microwaved food have circulated on the Internet for years- known as urban legends. As a result, the Food and Drug Administration continues to receive inquiries from concerned consumers. I've also received inquiries on this subject and I feel that it's time for an update.

Consumers can be confident as they heat meals or leftovers in the microwave that the FDA carefully reviews the substances used to make plastics designed for food use. These include microwave-safe plastic coverings that keep food from splattering and microwave-safe containers that hold frozen dinners. Even microwavable popcorn bags, which look like paper, actually contain a metalized plastic film that allows them to reach high temperatures so the corn can fully pop.

Under the food additive provisions of the Federal Food, Drug, and Cosmetic Act, new substances used to make plastics for food use are classified as "food contact substances." They must be found safe for their intended use before they can be marketed.

"It's true that substances used to make plastics can leach into food," says Edward Machuga, Ph.D., a consumer safety officer in the FDA's Center for Food Safety and Applied Nutrition. "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." The agency has assessed 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. The FDA will revisit its safety evaluation if new scientific information raises concerns.

One chemical called diethylhexyl adipate (DEHA) has received a lot of media attention. DEHA is a plasticizer, a substance added to some plastics to make them flexible. DEHA exposure may occur when eating certain foods wrapped in plastics, especially fatty foods such as meat and cheese. But the levels are very low. The levels of the plasticizer that might be consumed as a result of plastic film use are well below the levels showing no toxic effect in animal studies.

Other claims have asserted that plastic contains dioxins. "The FDA has seen no evidence that plastic containers or films contain dioxins and knows of no reason why they would," Machuga says.

Machuga says that consumers should be sure to use any plastics for their intended purpose and in accordance with directions. If you don't find instructions for microwave use, you should use a different plate or container that you know is microwave-safe. Such containers are made to withstand high temperatures.

For example, carryout containers from restaurants and margarine tubs should not be used in the microwave. Inappropriate containers may melt or warp, which can increase the likelihood of spills and burns. Also, discard containers that hold prepared microwavable meals after you use them because they are meant for one-time microwavable use.

Microwave-safe plastic wrap should be placed loosely over food so that steam can escape, and should not directly touch your food. "Some plastic wraps have labels indicating that there should be a one-inch or greater space between the plastic and the food during microwave heating," Machuga says.

I just happen to have Glad® Cling Wrap in my pantry and it states on the carton, "Unlike some other wraps, Glad® Cling Wrap contains no plasticizer." Then it gives directions for microwave use. This is the smart thing to do when purchasing plastic items- check to see if they are microwave safe.

Always read directions, but generally, microwave-safe plastic wraps, wax paper, cooking bags, parchment paper, and white microwave-safe paper towels are safe to use. Covering food helps protect against contamination, keeps moisture in, and allows food to cook evenly. Never use plastic storage bags, grocery bags, newspapers, or aluminum foil in the microwave. (Most information taken from FDA Consumer.)

FYI: Another urban legend - you've heard of dangers of freezing your plastic water bottles. There are no dioxins in plastics. In addition, freezing actually works against the release of chemicals. Actually, people should be more concerned about the quality of the water they are drinking rather than the container it's coming from. The truth is that city water is much more highly regulated and monitored for quality. Bottled water is not. It can legally contain many things we would not tolerate in municipal drinking water.

Claudia Parks, RN is a former doctor's office and emergency room nurse and retired as an educator from Fulton County Schools. She writes Your Health Matters as a public service; the information here is designed to help you make informed choices about your health. It is not intended as a substitute for the advice of your physician. Claudia and her husband make their home in the beautiful north Georgia Mountains. Claudia can be reached at yhm@windstream. net