1. Home
  2. Food
  3. Chemical Contaminants & Pesticides
  4. Process Contaminants in Food
  5. Testing Food for PFAS and Assessing Dietary Exposure
  1. Process Contaminants in Food

Testing Food for PFAS and Assessing Dietary Exposure

Method for Testing PFAS in Food

FDA scientists are at the forefront of developing new and more sensitive testing methods to measure very low levels of PFAS in food. Since 2012, the FDA has been refining the analytical method for measuring PFAS in foods by testing specific groups of food, as well as focusing testing efforts on foods grown or produced in areas associated with environmental PFAS contamination.

The types of PFAS the FDA tests for depends on the availability of chemical standards and is also informed by the scientific literature. For example, in the FDA’s 2022 survey of seafood some of the PFAS that were added to our method had been identified in the literature as being more prevalent in seafood.

Assessing Dietary Exposure to PFAS

To understand the potential dietary exposure to PFAS from food, the FDA has focused its testing on foods most commonly eaten by people in the United States and has conducted additional targeted sampling of certain types of food. The FDA also conducts testing of food grown or produced in areas with known environmental contamination, to detect and evaluate potential contamination of human and animal food.  

FDA Approach to Human Health Assessments

FDA conducts assessments on a case-by-case basis to evaluate whether PFAS levels detected in food present a potential human health concern. The FDA’s approach considers a number of factors, including how much of the specific food people typically eat, the level of the PFAS detected in that food, and scientific information on the toxicity of the specific PFAS detected.

As part of the FDA’s ongoing effort to use the best available current science to assess the exposure to PFAS from foods, the agency monitors the scientific literature and available toxicological reference values (TRVs) for PFAS and updates the values used for assessments, as warranted. 

There are currently ten PFAS (PFOA, PFOS, PFNA, PFHxS, HFPO-DA ⌈GenX⌉, PFBS, PFBA, PFHxA, PFDA, and 6:2 FTS) for which there are toxicological reference values that are used to assess the potential human health concern for levels found in food as a result of environmental contamination. These are the finalized minimal risk levels (MRLs) for PFNA and PFHxS from the Agency for Toxic Substances and Disease Registry’s May 2021 Toxicological Profile for Perfluoroalkyls, and EPA reference doses for PFOA, PFOS PFBS, HFPO-DA (GenX), PFBA, PFHxA, PFDA, and 6:2 FTS. Currently, FDA evaluates these PFAS individually in food samples and does not consider possible additive effects. However, we are exploring approaches for evaluating multiple PFAS co-occurring in samples. As the science continues to evolve for PFAS and TRVs are updated or new TRVs are established, our conclusions related to the potential human health concerns for certain levels of PFAS found in food may change.

Testing for PFAS in Total Diet Study Samples

The FDA has been working to better understand if food from the general food supply is a significant source of PFAS exposure for U.S. consumers. The FDA has been testing foods collected as part of the FDA’s Total Diet Study (TDS) since 2019. TDS foods are regionally and nationally distributed, are purchased at grocery stores, and represent the broad range of foods—breads, dairy, produce, meat, fish, poultry, as well as processed foods, such as macaroni and cheese, peanut butter, and salad dressing, etc.—the average U.S. consumer might eat.

The number of TDS samples for each type of food tested are limited, therefore, the FDA uses only a complete “market basket” consisting of 24 regional and two national collections to estimate nutrients and contaminants in the general food supply. For PFAS we are over half of the way there. Once we have tested a full market basket, we will be better able to estimate U.S. consumers’ exposure to PFAS from the total diet. 

The purpose of testing the TDS samples for PFAS is to better understand the general occurrence of PFAS in foods, determine if targeted sampling assignments are necessary for certain foods or types of food, and to help inform the agency’s approach to future surveillance efforts. For example, after testing of TDS samples showed that most of the detectable levels of PFAS were in seafood, the FDA conducted a targeted seafood survey in 2022.

Targeted Sampling of Seafood

In 2022, the FDA tested 81 samples comprised of clams, cod, crab, pollock, salmon, shrimp, tilapia, and tuna (2022 Seafood Survey) for PFAS. Detectable levels of PFAS in most of the seafood samples were determined to not be likely health concerns based on available PFAS toxicological reference values (TRVs) at the time. The results from this targeted seafood testing showed a greater percentage of samples had detectable levels of PFAS, more types of PFAS were detected, and the levels detected in multiple samples were higher when compared to previous TDS data.

The FDA determined that the estimated exposure to perfluorooctanoic acid (PFOA), a type of PFAS, from some of the imported samples of canned clams, which were from China, were likely a health concern. For canned clams from the 2022 seafood survey, voluntary recalls were issued by the two distributors.

Following the 2022 seafood survey, the FDA has continued to collect processed clams from China. Results of the additional testing of 12 samples of processed clams from the two processors associated with the highest levels of PFOA detected showed that all 12 samples had detectable levels of at least one type of PFAS; PFOA was detected in all samples. Three shipments were refused entry into the U.S.

In 2023, the agency also conducted a small survey of nine domestically acquired clam samples, six of which identified the U.S. as their country of origin, collected at retail establishments in the Washington, D.C. metro area. All but one of those nine samples had PFOA concentrations under the method detection limit. All clam products associated with these samples remained on the U.S. market. The agency engaged with the clam firms that had products sampled, including clams from China and the domestically acquired clams, to better understand potential sources of contamination and ways in which PFOA concentrations may be reduced.

Filter feeders, such as clams, but also other bivalve mollusks, including oysters, mussels, and scallops, may have the potential to bioaccumulate certain environmental contaminants to a greater degree than other seafood types. Additional sampling of bivalve mollusks (including mussels, oysters, scallops, and domestic and imported clams) was carried out in 2024 and 2025 for PFAS analysis, and the data are currently under review.

The results from the analysis of foods from the general food supply through the TDS will, along with other testing results, help to inform the FDA’s risk-based approach to identifying, prioritizing, and implementing the agency’s activities to reduce exposure to PFAS from human and animal food.

Back to Top