Reviewed by Brunilda Nazario, MD on June 05, 2019
From the WebMD Archives

Editors' note:  In October 2019, the FDA revised its test results for PFAS chemicals in food. The agency now says that the high level of a PFAS chemical found in chocolate cake and chocolate milk was a false positive. The test FDA scientists initially used couldn't tell the difference between chocolate and the PFAS chemical PFPeA. Levels of PFAS chemicals in meat and fish are also lower than first reported. The FDA says it has since retooled its test method for PFAS in food to produce more accurate results.  Experts say they have questions about some of these changes.


June 5, 2019 -- The FDA for the first time has tested food on grocery store shelves for a class of risky grease- and stain-repelling chemicals that are known to stick around in the body and the environment for a long time.

The chemicals, called polyfluoroalkyl substances, or PFASs, were found in samples of sweet potatoes, pineapples, chocolate milk, baked goods, and meats. The highest levels of PFAS compounds were found in a sample of chocolate cake with chocolate icing.

The results of the tests were presented on a poster displayed at a recent environmental toxicology conference in Helsinki, Finland. Someone attending the conference took photos of the poster and emailed them to environmental activists in the United States, who then alerted reporters.

The poster concludes that in most cases, the levels of contaminants found in food would not be a concern for health. That conclusion is based on an FDA safety assessment that did not provide details on how it was reached. Independent experts disagree.

“We think it is a big deal,” says Tom Neltner, chemicals policy director at the Environmental Defense Fund in Washington, D.C. “It’s FDA sampling showing not just contamination of food around hot spots, but contamination of food you’re going to buy in stores that nobody would suspect were contaminated,” he says.

“These concentrations in contaminated food are really highly elevated,” says Philippe Grandjean, PhD, an adjunct professor of environmental health at Harvard who co-directs the STEEP Center, a federally funded project to study the chemicals. STEEP stands for Sources, Transport, Exposure and Effects of PFASs.

“I think FDA needs to take action right now, first of all to monitor this better to figure out how big is this problem across the country,” Grandjean says. “This clearly shows it’s not just a drinking water issue. It’s also a food issue.”

Linda Birnbaum, PhD, director of the National Institute of Environmental Health Sciences and the National Toxicology Program, says she was surprised to learn of the food testing results from news reports instead of through her government partners. She, too, says the FDA’s conclusions were troubling.

“The poster kind of concluded that they didn’t think the levels were of concern. I think what we have to remember is that the agricultural products are only one source of exposure. We’re all exposed from multiple sources,” she says.

“Treating them as one-offs probably isn’t a health protective way to go,” Birnbaum says.

The FDA declined to comment on its findings. The agency posted a new web page about PFAS chemicals with some of its study results this week.

What the Tests Found

In October 2017, the FDA ordered testing of 91 samples of fruits, vegetables, meats, milk, and baked goods purchased at grocery stores in three unnamed cities in the Mid-Atlantic region.

The FDA tested mixed samples of pineapple, sweet potato, chocolate cake with chocolate icing, chocolate milk, and 10 different kinds of meat and fish. The samples were tested for 16 different kinds of PFAS chemicals.

Out of the 91 samples tested, 14 tested positive for at least one kind of PFAS.

The highest level of PFASs -- more than 17,600 parts per trillion (ppt) -- came from a sample of chocolate cake with chocolate icing.

The levels detected in the cake were so high, Neltner, of the Environmental Defense Fund, believes it must have rubbed off of the paper or cardboard the cake was packaged in.

Companies are supposed to notify the FDA when they use chemicals they’ve deemed safe in food packaging.

Neltner says he can find no such notification for the type of PFAS that tainted chocolate cake, PFPeA.

It’s impossible to know exactly how the cake was contaminated, though, because the FDA tested mixed samples taken from several different grocery stores without revealing which brands or stores were involved.

“One piece of cake, even though those levels are high, I’m not too worried about it. But if it’s from baked goods from that store, and it’s the paper that’s contaminated and you buy baked goods there every week, you can have significant exposure,” Neltner says.

“In terms of particular foods or particular food sources, the public is really in the dark,” says David Andrews, PhD, a senior scientist with the Environmental Working Group, which has been tracking PFAS contamination in drinking water.

“These results are confirming our concerns that these PFAS chemicals are present in our food supply and really highlight how the agency has really dragged their feet in terms of understanding the scope of this contamination,” he says.

The FDA found 765 ppt per kilogram of a PFAS chemical called PFOS in a sample of ground turkey. It found 865 ppt per kilogram of PFOS in a sample of tilapia.

The most consistent detections were found in meat. About half the meat and fish samples -- 10 of 21 -- tested positive for PFOS. At one time, PFOS was the main ingredient in Scotchgard stain repellent. It was also used in firefighting foams. In 2000, 3M, the major U.S. manufacturer of PFOS, agreed to stop producing it here, but it is believed to still be made in China.

While there’s no federal safety standard or risk level for PFOS in food, some states have posted warnings to fishermen and hunters about levels of PFOS in fish and game caught near contaminated areas.

The Alabama Department of Health, for example, says fish with less than 40,000 ppt of PFOS are safe to eat with no restriction. Testing of fish in the Wheeler Reservoir, near a 3M plant that produced PFOS, found largemouth bass with concentrations of 800,000 ppt. Those fish were deemed not safe to eat.

Fish isn’t the only kind of food affected.

In the study presentation, the FDA also reported finding PFAS chemicals in produce -- lettuce, collards, cabbage, and kale -- purchased at farmers markets downstream from the polluted Chemours chemical plant site near Fayetteville, NC. Leafy greens grown within 10 miles of the plant had the highest levels of the chemicals.

The FDA’s testing also delved into another worrisome situation: PFASs in milk.

Because the chemicals travel with proteins through the body, they concentrate in human and animal breast milk, says Grandjean. A nursing mother can cut the amount of PFAS in her own body by about 50% over 6 months of breastfeeding. The problem is that the chemicals then concentrate in the body of her baby.

At least two dairy farms in the U.S. -- one in New Mexico and one in Maine -- recently shut down because of high levels of PFAS contamination in their milk. In one case, the farm was near a contaminated Air Force base that had polluted local wells, including those used to water the cows. In another case, cows were contaminated by sewage sludge loaded with PFASs that were spread on farm fields.

No one knows how widespread the problem of PFAS contamination may be within the dairy industry because there’s no routine monitoring for the chemical in milk.

So far, dairy producers say they believe these two situations were isolated.

“We’re all trying to get our arms around the size and scope of this problem,” says Alan Bjerga, a spokesman for the National Milk Producers Federation. “Thus far, from what we’ve seen, it doesn’t seem to be a widespread issue for dairy.”

An ‘Emerging Contaminant’

PFASs have been used for decades in a wide variety of consumer products -- from nonstick pans, to rain jackets, to firefighting foam, food wrappers, personal care products, and stain-resistant carpets. Industrial dumping of the chemicals around plants that made them and military bases that used them has created Superfund sites where residents are being monitored for a slew of health problems, including high cholesterol, infertility, cancers, thyroid problems, and autoimmune diseases.

So far, research has shown that many PFASs appear to disrupt hormones and interfere with the immune system.

But it’s not just people who live around contaminated sites who are at risk.

The CDC says nearly all Americans have detectable levels of PFASs in their blood. Those levels have been dropping as companies -- under pressure from the Environmental Protection Agency -- have stopped U.S. manufacturing of some of the most highly toxic kinds.

But thousands of other kinds of PFASs are still being produced and used, and little is known about how much we’re exposed to and what they’re doing to our bodies.

Grandjean and other experts interviewed for this story feel the background levels we’re all exposed to are still too high.

The PFASs are defined by an extremely strong chemical bond that makes them nearly impossible to get rid of.

“You have to go to well over 1,200 degrees to break it down,” says Birnbaum. “We learned with DDT years ago, we don’t want things that don’t go away. Why are we making these?”

The chemicals persist in nature and in our bodies for months to years, depending on their structures. For that reason, they can build up over time.

Unlike other “forever chemicals” like PCBs, which are stored in fat, PFASs are carried by proteins. They concentrate in organs like the liver and kidneys.

The chemicals have recently turned up in drinking water in at least 33 states and Puerto Rico, in the water on some military bases, in the water that leaches from landfills, and in sewage sludge used to fertilize farm fields. Industrial dumping sent them sluicing down major waterways like the Mississippi River and into the oceans. They are now so pervasive that scientists have even found them in the blood of Arctic seals and polar bears.

The EPA considers them to be “emerging contaminants.” It has set a health advisory level of 70 parts per trillion for drinking water. The level is meant to let local water utilities know when they have a problem that needs to be cleaned up, but it is not an enforceable standard.

There are no federal safety standards for PFASs in food.

An Attack on the Immune System

The various ways that PFASs may affect the body are still under study, but one clear route of harm appears to be the immune system.

 Grandjean considers the chemicals to be immunotoxicants, or poisonous to the immune system.

He and others have shown that exposure to PFAS compounds appears to make some kinds of vaccines much less effective.

Vaccines work by spurring the body to make protein defenders called antibodies that stick to viruses and help the body fight them off. But children who are exposed to higher levels of PFAS chemicals don’t make as many protective antibodies as they should.

“For every doubling in the PFAS concentration in the blood, we see that the kids -- at least for certain vaccines -- they lose 50% of the antibody concentration. So you can see with a few doublings, you lose 50% every time,” Grandjean says.

Grandjean says he has wondered whether PFAS exposures may not be at least partly to blame for the resurgence of childhood diseases like measles and whooping cough.

In addition to making vaccines less effective, Grandjean says other studies have shown that immune problems linked to PFASs may drive allergies and autoimmune diseases. With the immune system out of whack, he says, cancer may get a foothold more easily, too.

“This is an important public health problem that we are being unwittingly exposed to immunotoxicants and we don’t quite know the extent of the impact on public health,” he says.

“In my mind, these compounds must be taken seriously, and we must do what we can to minimize exposures.”

Right now, that’s not easy to do, since testing for PFASs has been limited.

Until more is known about specific exposures, Birnbaum says the best ways to protect yourself from PFAS contamination are to:

  • Eat fresh food. Studies have found about half of fast-food containers and bakery wrappers contain these chemicals.
  • If you live in an area where there’s evidence of contamination, consider filtering your water. The state of Michigan has posted some information on home water filters that cut levels of PFAS chemicals.
  • Keep your house clean. Environmental chemicals, including PFASs, concentrate in house dust.

“I’m not a white glove kind of person, but keeping dust down is probably a good idea,” Birnbaum says.

For more information:

Show Sources

Tom Neltner, chemicals policy director, Environmental Defense Fund, Washington, D.C.

Philippe Grandjean, PhD, adjunct professor, environmental health, Harvard University, Boston; co-director, Sources, Transport, Exposure and Effects of PFASs (STEEP) Center, University of Rhode Island, Kingston.

Linda Birnbaum, PhD, director, National Institute of Environmental Health Sciences and the National Toxicology Program, Durham, NC.

David Andrews, PhD, senior scientist, Environmental Working Group.

Alan Bjerga, senior vice president, communications, National Milk Producers Federation, Washington, D.C.

SETAC Europe, 29th Annual Meeting, Helsinki, Finland: “Investigation of Per- and Polyfluoroalkyl Substances in U.S. Food Products.”

Fish Consumption Advisory Sheet -- PFOS, Alabama Department of Public Health.

EPA, Draft Interim Recommendations to Address Groundwater Contaminated with Perfluorooctanoic Acid and Perfluorooctane Sulfate, April 2019.

Agency for Toxic Substances and Disease Registry (ATSDR): Toxicological Profile of Perfluoroalkyls, Aug. 20, 2018.

Environmental Defense Fund-Health: “FDA finds surprisingly high levels of PFAS in certain foods -- including chocolate cake,” June 3, 2019.

Environmental Working Group: PFAS Contamination in the U.S., Accessed June 4, 2019.

FDA: “How U.S. FDA’s GRAS Notification Program Works.”

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