Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: THURSDAY, March 22, 1990 TAG: 9003222280
SECTION: EXTRA PAGE: E3 EDITION: METRO
SOURCE: CHARLYNE VARKONYI THE BALTIMORE SUN
DATELINE: LENGTH: Long
"The containers and packages you microwave with - your cling-wraps, special `browning' packages and even your `microwave-safe' cookware - all could be releasing potentially harmful substances into your food," reported the Center for Science in the Public Interest in Nutrition Action, the group's newsletter. The center, a non-profit consumer group, has a track record of lobbying for food issues such as more informative nutritional labeling and health warnings on alcoholic beverages.
Although many of the items were not tested at high microwave temperatures before marketing, representatives of the packaging and processing industry insist that their products do not present a health hazard. Safety studies are continuing while the products remain on the market.
The U.S. Food and Drug Administration has given the microwave packaging industry until April 7 to gather data on the safety of "heat susceptors" - those thin, gray strips or disks of metallized plastic film on microwaveable packaging that cause food to brown at high temperatures. The film heats when exposed to the microwaves and can reach 350 degrees in 20 seconds, making popcorn easier to pop, and crisping prepared foods like french fries and pizza that otherwise would remain soggy.
"If we thought there was a real imminent health hazard, we would have pulled these products off the shelves quite a while ago," says Lester Borodinsky, a chemist with the FDA's Division of Food Chemistry and Technology. Borodinky's division conducted preliminary safety tests on the controversial heat susceptors.
And yet, the FDA still has a lot of unanswered questions. Borodinsky says the FDA does not have enough data to know what actually happens when the susceptor components are heated to high temperatures in a microwave. Manufacturers have been asked to identify chemicals that may leach into the food from the packaging and to determine what health hazard, if any, they pose. If new regulations are necessary, they will take at least another year to go into effect.
The heat susceptor packaging was never approved by the FDA before marketing. The FDA approves all substances that go into food packages under its indirect food additives regulations, but it does not approve the finished package. And when the FDA approved the separate components of susceptor packaging, the regulators never anticipated that they would be combined or that they would be used above 300 degrees.
"Our crystal balls weren't very good," Borodinsky says. "Twenty years ago there weren't many microwave ovens, and many of our regulations were written without upper temperature limits."
Soon after the heat susceptors started appearing a couple of years ago, the FDA chemists thought they should do some preliminary tests to see what happens to the components. They found:
Parts of the package can reach 500 degrees - 200 degrees above the approved temperatures.
All packages tested showed varying degrees of breakdown of the metallized polyethylene terphthalate film, or PET, including cracking and melting. When this happens, the protective barrier breaks down and chemicals can migrate into the food.
Since many of the foods using susceptors contain a substantial amount of fat, corn oil was used to measure the migration of the PET. When the corn oil was heated for three minutes in the microwave, 95 percent of the PET migrated out of the heat susceptor into the oil. This is six to 10 times higher than the level the FDA considered safe in evaluating PET for use in food packaging.
High temperatures also caused the adhesives and the paper in the susceptors to pass through what is supposed to be a functional barrier to protect the food. Detectable amounts of volatile chemicals - primarily from the adhesives and the plastics - were found in the oil after it was heated in a boat-shaped susceptor for 3 minutes.
"We did find benzene, toluene and xylene from the package in some cases," Borodinsky says. "The industry is aware of this and of course it is of great concern to the companies that make these products."
There is no evidence that toluene and xylene cause cancer in animals, according to the National Toxicology Program.
The most concern is over benzene, a known carcinogen that is derived from petroleum and used in the manufacture of DDT, insecticides and motor fuels.
Another controversial cooking item is the plastic cling-wrap that is used for everything from wrapping meat to covering dishes for reheating in the microwave.
The Center for Science in the Public Interest's Lefferts warns that no one knows how safe these wraps are and cooks should avoid putting them in direct contact with food - a recommendation of the British government. She cites studies that have raised serious questions about safety of some cling wraps containing PVC, also known as polyvinyl chloride.
Back in 1987, a British government study showed that the plasticizer commonly used in PVC plastic wraps, DEHA, migrates into fatty foods during microwave cooking. The higher the heat, the higher the migration. The study found lesser migration at room temperatures and in the refrigerator. DEHA will also migrate into non-fatty foods, such as fruits and vegetables, but in much smaller amounts than in the fatty foods.
In the United States, the National Toxicology Program has published a report implicating DEHA as a carcinogen in mice, but not in rats. Additional animal studies by the Chemical Manufacturers Association show carcinogenic effects differ according to sex and species, according to an FDA scientist familiar with the studies.
"DEHA is carcinogenic and when it is heated it breaks down," the FDA scientist says, noting there is not enough data to indicate a carcinogenic effect in humans.
Despite the scientific uncertainty, he advises that consumers avoid cooking any kind of food wrapped in any kind of plastic wrap - whether or not the wrap contains PVC.
Anne Waring, a spokeswoman for Reynolds plastic wrap, a product made from the controversial PVC, disagrees. She maintains the Reynolds product is safe and it can be used in direct contact with food.
The FDA, not foreseeing the advance of high technology into food packaging and preparation, gave up its jurisdiction over products that are used for cooking and eating in the home back in the 1950s. Most of the companies say they test their products and they are indeed "microwave safe" or "microwave approved," but no government agency is looking over their shoulders to making sure their claims are true.
by CNB