It doesn't matter how many smiling cartoon characters decorate a package. If food comes in a can, it's likely to contain the worrisome chemical bisphenol A, or BPA, according to a new study.

The study, which looked at six popular name-brand products, adds to accumulating evidence that the hormone-interfering chemical is widespread in our food supply and in the bodies of most Americans, including children.

Advocacy groups have successfully managed to get companies to remove BPA from baby bottles, sippy cups, pacifiers and other products made for small children. The new findings suggest that food cans might need to be their next major target.

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"Every single can we tested had BPA, and they could potentially expose people at levels of concern," said Connie Engel, science education coordinator for the San Francisco-based Breast Cancer Fund, which released the new study. "We know that consumer pressure on the market can lead to changes. If enough of us talk about this, the market will respond and we'll have BPA-free foods."

Among its many other qualities, BPA is extremely useful as an ingredient in the epoxy-resin lining of food cans. With its flexibility and resistance to both corrosion and the high heats used during sterilization, BPA is extraordinarily effective at preventing spoilage of food with pathogenic bacteria.

But BPA may bring dangers of its own, according to accumulating evidence. In cell and rodent studies, the chemical has been linked to all sorts of reproductive and developmental problems, including cancers, diabetes, early puberty and attention deficit disorders. And because of their small body sizes and the developing nature of their organ systems, children are most sensitive to the chemical's effects.A slew of recent studies have shown that BPA can seep into food that is packaged in all kinds of materials, particularly in the linings of cans. Other research has found that nearly all preschoolers harbor BPA in their bodies, primarily as a result of the food they eat. And when people stop eating canned and plastic-packaged foods, the level of BPA in their bodies goes down.

To zero in on the main sources of exposure for kids, Engel and colleagues gathered six types of popular canned products that are marketed directly to children. Some showed cartoon characters or kids on their labels. Other labels claimed things like, "Taste kids love!"

The researchers sent two of each product -- one from a grocery store in the Bay Area and one from a market in Wisconsin –- to an independent testing lab. On average, soups contained about 77 parts per billion of BPA, and prepared meals contained 21 ppb. Those levels were on par with what other studies have found in canned foods made for adults. It didn't matter whether products were organic or conventional.

The highest levels of BPA, ranging from 71 ppb to 148 ppb, appeared in cans of Disney Princess Cool Shapes Shaped Pasta with Chicken in Chicken Broth and cans of Toy Story Fun Shapes Shaped Pasta with Chicken in Chicken Broth, both made by Campbell's. Earth's Best Organic Elmo Noodlemania Soup and Annie's Homegrown Organic Cheesy Ravioli fell in the middle. At the bottom, with levels ranging from 10 to 21 ppb, were Chef Boyardee's Whole Grain Pasta Mini ABC's & 123's with Meatballs and Campbell's Spaghettios with Meatballs.

Scientists don't yet know how much BPA a product needs to contain before it starts causing health issues. Some experts and industry groups argue that our bodies metabolize BPA too quickly to make these kinds of levels problematic. And there are also no studies that definitively demonstrate harm in humans.

But other scientists think that any amount of BPA is too much, especially considering that so many everyday products contain the chemical, including cash register receipts, measuring cups and CDs.

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Animal studies show that tiny amounts of BPA can cause breast cancer and other problems, said William Goodson, a breast surgeon at the California Pacific Medical Center Research Institute in San Francisco. In a lab study published last week in the journal Carcinogenesis, he and colleagues also found that BPA causes two changes in cells that make them more vulnerable to cancer. Controlled studies can't be done on people, he added, because 95 percent of us already harbor detectable levels of BPA in our bodies.

The new study "is additional evidence that this sort of stuff is being dumped on all of us all the time," Goodson said. "The bottom line is that the food that kids get and are encouraged to eat by manufacturers have a lot of BPA in it."

Parents may want to consider avoiding liquid foods that have prolonged contact with cans or plastic containers, Goodson said, especially when they are particularly acidic or sour. Instead, the report recommends other types of inexpensive convenience foods, such as frozen meals, soups in Tetra Pak cartons, dried fruits and boxed macaroni and cheese.