Cookware metal can turn a healthy meal into a harmful one

May 19, 1993|By Stevenson Swanson | Stevenson Swanson,Chicago Tribune

The recipe for that great marinara sauce says nothing abou adding a pinch of aluminum, and lead is nowhere to be found on the menu for the elegant dinner served on the family's best china.

Yet these and other unannounced ingredients -- copper, iron and plastic coatings -- can find their way into food and then into human beings through pots, pans, plates, microwave crisping sheets and other cooking and serving pieces.

It only makes sense that subjecting metal utensils and ceramic plates to high temperatures, hot liquids, salty or acidic foods and sharp objects will jar loose bits of metal or cause minerals to seep from the abused surfaces.

But what this fact means to human health is another matter. As with so many controversies in health and environmental affairs, easy answers to questions about the safety of cookware and china are not easy to find.

Hard, but not impossible. And the most serious health risks are easily avoided by following a few simple suggestions.

Of all the raw materials used to make utensils and dinnerware, of most concern is lead, which is used widely in the glazes that coat ceramic dinner plates, cups and bowls. And lead can account for a quarter of the weight of a piece of leaded crystal.

Lead poisoning leads to a host of health problems, but the most serious are its effects on the central nervous system. Young children and those yet unborn, the two groups most susceptible to lead poisoning, can suffer slowed mental development, which leads to impaired learning abilities and, in extreme cases, mental retardation.

Government regulations establish how much lead may leach from ceramics into food, and spot tests indicate the majority of dinnerware meets those standards, with imported pieces faring less well than domestic china. But those tests cover an infinitesimal proportion of the 1.2 billion pieces of ceramicware sold yearly in this country, and there is no way to tell simply by looking at a plate whether it is a lead-leacher or not.

If it seems unlikely that so much lead could escape into food to make someone sick, consider the case of Marco Tulio Rey, a Westchester County, N.Y., man who in 1987 complained of severe stomach pains. A blood test revealed unusually high lead levels.

While he was hospitalized for lead poisoning, other members of his family reported that they felt abnormally fatigued and suffered dizziness. Public-health officials eventually traced the cause to a broken jug a friend had brought back from Mexico. The Reys used it to store a fermented bean drink, which had eaten away at the glaze.

The key fact was that the bean drink was acidic. Foods and liquids most likely to cause lead to leach out of a ceramic glaze or crystal are acidic products, such as the bean drink or tomatoes, citrus fruits, apple juice, coffee, wine and vinegar. Hot liquids also can speed up the leaching of lead.

Tests have shown that lead levels in port wine stored in a lead-crystal glass shoot up from 89 parts per billion to 3,518 parts per billion after four months, not such a far-fetched amount of time if port is kept in a crystal decanter. In another study that used port with 33 parts per billion of lead, levels increased to 68 parts after one hour, 81 after two hours, 92 after three hours and 99 parts after four hours, according to Barry Swanson of the food science department at Washington State University.

Because of such results, Ernest Foulkes, an environmental health professor at the University of Cincinnati, advises against using leaded crystal for wine or other alcoholic beverages. In general, he says, ceramic bowls and plates should not be used to store acidic foods.

Since 1969, when a California family suffered acute lead poisoning by drinking orange juice stored in a Mexican ceramic pitcher, the Food and Drug Administration (FDA) has set limits on the amount of lead that glazes may allow to leach into foods.

Over the years, the limits have been tightened, in part because studies have suggested that lower levels of lead than previously thought can cause health problems. Also, lead glazes have become a more important source of exposure as other sources have been shut down. For instance, leaded gasoline, by far the single greatest source of lead exposure in the past, almost has disappeared. Lead solder once was used in cans. Now, almost no cans produced in America are lead-soldered, although imported foods may be packed in lead-soldered cans.

In 1991, the FDA again tightened lead standards for ceramic glazes. The limits vary, depending on the size and type of ceramic piece. The standards are tightest for cups, mugs and pitchers, the items most likely to be used repeatedly or used to hold liquids most likely to cause lead leaching. After holding a vinegar solution for 24 hours, these items can leach no more than 0.5 of a part of lead per million parts of the liquid. That is a drastic reduction from the previous standard, which allowed as many as 5 parts of lead per million.

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