Is It Safe to Heat Food in Plastic?

Where Chemicals Lurk continued...

The results: When food was heated in these containers in the microwave (or, in the case of Press 'n Seal, in a glass bowl covered with the wrap prior to microwaving), all three suspect products passed: "No detectable amounts" (to use the scientific phrase) of BPA or phthalates wound up in either the tomato sauce or the gravy.

While this is terrific news, there's more you should understand. For one thing, we know we have these chemicals in our bodies, and they're getting there somehow. Indeed, nearly every American has BPA coursing through his or her veins, according to data gathered in 2003-04 by the Centers for Disease Control and Prevention — and children have the highest levels of all. The FDA estimates that adult Americans consume, on average, a cumulative 11 micrograms of BPA per day through diet — mostly from the liners in canned foods, say several scientific groups. Is that level a lot? Is it safe? No one really knows yet, but "we're concerned about how much exposure there is to this chemical and possible health repercussions," says Anila Jacob, M.D., a physician and senior scientist for the Environmental Working Group (EWG), a nonprofit watchdog scientific organization.

Nor does anyone know for sure whether BPA accumulates in humans over time, though most scientists believe adults process it quickly — in as little as a day. However, the fact that so many of us have the compound in our bodies means that we're exposed to it daily, says Dr. Jacob. And fetuses and babies may not metabolize the chemical as well as adults, other experts point out, so it's possible that it builds up in their small bodies.

Just Can These

The insides of food cans are often lined with an epoxy resin that keeps corroding metal away from the food. But bisphenol A in that resin can migrate into the foods; in fact, it's the major source of our exposure to the chemical, says the government's National Toxicology Program. While the FDA has issued reassuring statements about the risk, other experts aren't so convinced. In 2007, the nonprofit Environmental Working Group found BPA in more than half of the 97 food cans it tested, with the highest levels coming from chicken soup, infant formula, and ravioli. Just one to three servings of those foods with those concentrations could expose a woman or a child to BPA at levels that cause serious adverse effects in animal tests, the group concluded.

Though you may see "BPA-free" on some canned goods, food manufacturers are not required to list the chemical on labels, so you have no way of knowing whether it's present. To limit your family's exposure:

• Buy more fresh or frozen fruits and vegetables.
• Choose soups and broths that come in aseptic boxes or dried soup mixes in nonplastic bags.
• Be extra cautious with infants: If you use commercial formula, buy it in powdered form, which comes in a foil-lined cardboard container and shouldn't have any BPA, says the FDA.
• Use BPA-free baby bottles and sippy cups.