Is That Newfangled Cookware Safe? : Part 2

by Food and Drug Administration (FDA)

(Page 2 of 3)

Anodized Aluminum

One reason that aluminum became popular for cookware is that it is an excellent heat conductor. Heat spreads quickly and evenly across the bottom, up the sides, and across the cover to completely surround the food.

Now cookware manufacturers have developed a process for treating aluminum that retains the heat conductivity properties of the metal, but changes aluminum in other ways. The process, called anodization, involves a series of electrochemical baths that thicken the oxide film that forms naturally on aluminum. This supplemental coating hardens the metal, making it more scratch resistant. Food barely sticks on the hard, smooth surface of this altered aluminum, making it easier to clean.

Commercial Aluminum Company, the manufacturer of Calphalon, a best-selling brand of anodized aluminum cookware, claims that a final stage in the anodization process seals the aluminum, preventing any leaching into food. Anodized aluminum cookware doesn't react to acidic foods, so these pots and pans are top choices for cooking rhubarb and sauces with tomato, wine, and lemon juice.

Nonstick Coatings

Before anodized aluminum made its cookware debut, nonstick coatings stirred a mini-revolution in the American kitchen. Teflon, for instance, is a trademark for a tough, nonporous material called perfluorocarbon resin that permits cooking without the use of fats. It was first discovered by chance in 1938 and then hurried into wartime production for use in radar systems, in which other less durable substances had failed.

The noncorrosive properties of this stable plastic material made it a natural for cookware. In 1960, FDA approved its use for food contact surfaces, and cookware manufacturers began turning out pots and pans with a coating that cleaned quickly and easily and that required less fat for nonstick cooking. One of the first nonstick coatings to be applied to housewares, Teflon soon became a household word.

Fry pans were the first cookware marketed with this nonstick finish. Now, says the Cookware Manufacturers Association, almost every cookware and bakeware item is available with a nonstick finish. There are griddles, saucepans, casseroles, muffin pans, cookie sheets, Dutch ovens, egg poachers, cake pans, deep fryers, and waffle bakers.

Because nonstick finishes may be scratched by sharp or rough-edged kitchen tools, manufacturers recommend using plastic or wooden utensils. Abrasive scouring pads or cleansers should not be used to clean them. Even so, Tom Brown, an official in FDA's food additives section, notes that while nonstick pans do abrade with hard use and particles may chip off, these particles would pass unchanged through your body and pose no health hazard.

When heated for long periods at high temperatures, the resin decomposes. However, a 1959 study, conducted before FDA approved the material for use in food processing equipment, showed that the toxicity of fumes given off by the coated pan on dry heating was less than that of fumes given off by ordinary cooking oils. The study, conducted by the Haskell Laboratory for Toxicology and Industrial Medicine, compared effects of inhaling of fumes from resin-coated pans that were overheated?for four hours at 250 degrees Celsius (482 degrees Farenheit) with corn oil, peanut oil, and butter.

The investigators, J. Wesley Clayton, Ph.D., and Gayle E. Raynesford, also explored the possibility that long-term use of the coated pan also increases the chance of food contamination with the resin. Newly coated resin pans, an aged pan (a pan that had been heated at 250 degrees Celsius (482 degrees Farenheit) for 159 hours), and a pan that had received two-and-one-half years of domestic use were used to fry hamburger meat.

Researchers compared the results with those from frying hamburger in an uncoated aluminum pan, measuring levels of fluoride, which serve as an index to Teflon residue. (Aluminum contains traces of fluoride as impurities.) An analysis showed basically the same amount of fluoride in the hamburger cooked in the new resin-coated pan as in the one cooked in the plain aluminum pan. Slightly more fluoride but well within safe limits showed up in the hamburgers fried in the heat-aged pan and the old pan.

Cooking enthusiasts now are hailing Silverstone and Excalibur nonstick coatings, which are made of three layers of the same plastic used on Teflon and other perfluorocarbon resin-coated pans. This material is extremely durable, and so inert (meaning it will not migrate) that it is used in artificial arteries, hip joint replacement parts, and other surgical implants. As with Teflon, however, it will emit fumes when overheated. Out of caution, DuPont refuses to license housewares manufacturers to produce from Silverstone burner bibs (the pans that are placed under stove burners) because these pans can become extremely hot.

The newest rage, says a chef and salesperson in the cookwares section at an exclusive Washington, D.C., department store, is a brand that combines hard anodized aluminum with a nonstick coating. A Los Angeles Times food critic reported last year that when testing such a pan, he toasted cheese to death until it was crusty and browned and cooked a whole egg until it was picture perfect. . . . Cleaning was a cinch. The Washington, D.C., chef says that coated anodized aluminum is nonstick for life.

Stainless Steel

Consumers who don't buy aluminum pots and pans usually buy stainless steel. Uetzmann says that stainless steel accounts for 43 percent of cookware sold today. Stainless steel cookware and bakeware is exceptionally durable. Says Uetzmann, Its attractive finish won't corrode or tarnish permanently, and its hard, tough, nonporous surface is resistant to wear.

Like other steels, stainless steel is an alloy a combination of iron and other metals. Unlike other steels, however, it contains at least 11 percent chromium. This chromium makes the steel stainless all the way through.

According to the Cookware Manufacturers Association, stainless steel may also contain other elements, such as nickel, molybdenum or titanium. These materials can contribute special hardness, high temperature resistance, and resistance to scratching and corrosion to the finished stainless steel alloy.

As stainless steel does not conduct heat evenly, most stainless steel cookware is made with copper or aluminum bottoms. Manufacturers caution against allowing acidic or salty foods to remain in stainless steel for long periods. Although there are no known health hazards from leaching of the metal, undissolved salt will pit steel surfaces.

About the Author

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FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.