The chemical has been linked to all sorts of health concerns, including heart disease, cancers, and developmental problems.
Canned foods may be a source of BPA exposure, along with packaged foods.
The amount of BPA in grocery store foods varies from product to product, but overall levels are very small.
Scientists still don't know how much BPA is too much, or how it interacts with other chemicals in our food.
There are traces of the worrisome chemical BPA in a wide variety of canned foods from supermarket shelves, found a new study. BPA is also present in products packaged in plastic and in one sample from the deli counter.
The study, which was the first to measure levels of BPA in grocery store foods in the United States, suggests that food -- especially canned food -- might be one major route that BPA uses to get into our bodies.
The chemical, also known as bisphenol A, has been linked to all sorts of health concerns, including heart disease, cancers, and developmental problems. One new study linked higher levels of BPA exposure with lower levels of sperm in men.
The amounts of BPA found in the food samples were far lower than recommended limits, but that shouldn't necessarily offer much comfort, said lead researcher Arnold Schecter, a public health physician at the University of Texas School of Public Health in Dallas.
People eat a variety of foods that may be contaminated with the chemical, he pointed out. We get exposed to BPA from a number of sources (including, according to recent research, cash register receipts). Some scientists think that recommended limits should be five times lower than they are now.
What's more, BPA isn't the only chemical of concern found in our food supply. There might be hundreds of toxic chemicals in our meals, Schecter said, and experts don't know enough about how all these chemicals interact to affect our health.
"The so-called safe levels of acceptable daily intake are derived as though there are no other chemicals present, and that's not true," he said. "I do not feel comfortable with finding these levels of BPA in U.S. food."
"I'm not happy," he added, "that we found BPA in so many foods."
For industrial purposes, BPA is a useful chemical that makes plastics strong and lightweight for use in water bottles, DVDs, electronics and many other products. BPA is also a major ingredient in epoxy resins, which among other uses, help extend the shelf life of canned foods.The chemical is so ubiquitous that nationwide studies have found it in the bodies of the majority of Americans tested.
To investigate the link between canned foods and BPA exposure, Schecter and colleagues gathered more than 30 types of products from grocery stores in Dallas, and took up to three samples from each kind of product.
Out of 105 total samples, their analyses found detectable levels of BPA in 63 of them, the team reported in the journal Environmental Science & Technology, including three out of eight samples of cat and dog food.
Canned foods had the highest levels of the chemical, with Del Monte Fresh Cut Green Beans at the top of the list, followed by three types of Progresso soups.
Smaller amounts of the chemical showed up in a plastic container of Chef Boyardee Spaghetti and Meatballs, canned Enfamil infant formula, and Chicken of the Sea Chunk Light Tuna in Water. A variety of canned vegetable juices, fruit juices and soups also had traces of BPA.
There was no detectable BPA in Similac infant formula, Bumble Bee Chunk Light Tuna in Water, Chef Boyardee Mac and Cheese, or Hunt's 100% Natural Tomato Paste. Canned pineapple, some soups, and a few other products also came up negative.
The researchers couldn't find any patterns in BPA levels by food type or brand. They did not contact companies to ask about their packaging methods.
To follow up, Schecter said, his team has tested a wider range of products. They expect results to come in over the next few months.
Overall, levels of BPA were low, even in the products that had the greatest amounts. To reach what the U.S. Environmental Protection agency considers the maximum daily intake of BPA, for example, a 155-pound adult would have to eat more than 140 cans of green beans. A 45-pound child would have to eat more than 40 cans.
Still, experts say, the fact that BPA is in our food at all is enough to warrant a closer look -- both at other kinds of food and the levels we consider safe, said John Meeker, an epidemiologist at the University of Michigan School of Public Health in Ann Arbor.
"Even if the levels are considered low, there are multiple sources of BPA and you don't just eat one thing in a day," Meeker said. "There are a number of animal studies suggesting that there are health effects at lower levels than those thought to be acceptable. That's consistent with a number of new human studies related to health outcomes."
If you're concerned about BPA, Meeker said, you might want to choose fresh foods over canned versions. To limit pesticides as well, organic is also better. But both steps cost more, and that's a roadblock for many consumers.
Schecter emphasizes the need for manufacturers to find BPA-free canning methods. For now, Eden Organic may be the only U.S.-based food company that claims to can their beans without the chemical -- though Schecter is not sure if that has been independently verified, and Eden's cans are significantly more expensive than generic brands.
National health agencies, Schecter added, need to step up with better oversight.
"To the best of our knowledge, there is no government agency that does regular screening of our food for toxic chemicals," he said. "If these were to be done, we might detect patterns which would help us to decrease the numbers and levels of toxic chemicals in American food."