Q&A: Challenges of Addressing PFAS in the Food Supply

Commonly referred to as “forever chemicals,” PFAS are ubiquitous and environmentally persistent industrial chemical contaminants found in soil, sediment, fresh water sources, oceans, and other matrices. While PFAS chemicals have been around since the 1940s, there has been a renewed international emphasis in the last decade or so limit consumer exposure due to the chemicals’ negative effect on human health.

In the United States, the Environmental Protection Agency and state agencies have established maximum contaminant levels for drinking water and groundwater. However, there are currently no federal or state safety standards related to PFAS for soil in grazing or foraging areas, or for animal feed. Likewise, there are no federal safety standards for PFAS levels in food products. Labcompare Editor-in-Chief Michelle Taylor recently spoke to Richard Jack, Ph.D., Global Market Development Manager for the Food, Cannabis and Environmental Markets at Phenomenex, about why that is, and what we can expect to see in the future to address these concerns.

Q: How do PFAS chemicals get in foods and food packaging in the first place?
A: PFAS can enter food through a variety of ways. Plants, such as grass, can absorb PFAS from contaminated soil, then if cows eat contaminated grasses, they in turn will accumulate PFAS in their tissue. Other plants such as grains and feed can accumulate PFAS from contaminated soil and subsequently can find its way into chickens, fish, and pigs. A list of the target matrices and examples is shown in the table below. Food packaging has also been identified as a route for PFAS contamination. Plastics and recycled paper can become contaminated during manufacturing. Paper can become contaminated from trees that have been sprayed with firefighting foams which are used to put out forest fires. This leads us to food processing equipment that has Teflon components or is cleaned with pfas contaminated solvents. I know that there is an effort underway with ASTM to develop a procedure to clean and certify PFAS free food processing equipment.

The table below shows a list of food matrices that lists various food matrices that should be tested for PFAS contamination. This list has been created by AOAC to identify top food categories that have been shown to contain PFAS compounds that will be evaluated for an upcoming validated method.

Q: Why do you think, thus far at least, that the U.S. has focused legislation and safety standards on soil and drinking water when it comes to forever chemicals?
A: My impression is that most people are concerned about safe drinking water, and for a practical matter, the majority of people in developed countries receive their drinking water from a government-controlled water treatment facility. This means that it’s quite easy to treat drinking water because it comes from one source before it’s consumed. Yes, there’s bottled water, but not to the levels consumed from a drinking water utility. If any contaminants are found, they can be easily treated due to the single source. This is obviously not the case for foods which come from multiple sources.

Q: Are there different analytical challenges for testing in foods compared with drinking water?
A: Definitely! The sample preparation is much more complicated because food matrices require extraction. Food requires homogenization, some foods such as grains require grinding, milling or freeze drying to break the cell structure of the food to release the PFAS contaminant. This can be followed by a solvent rinse, addition of water, salts, vortexing, shaking, centrifugation and so forth. Drinking water simply requires loading the sample onto a solid phase extraction cartridge or just a direct injection. From an analytical challenge, food and waste waters can contain compounds known as cholic acids that are known to cause interference (signal suppression in the Mass Spec) for PFOS in foods such as eggs, milk, liver, meat, and seafood.

Q: Are there technology challenges/capabilities the lab industry needs to overcome to more effectively test for PFAS in foods and packaging? Or is it more about developing the correct methods?
A: In my opinion the separation and detection exist for the current PFAS compounds that are being tested. New methods may be needed if longer chain or some other forms of PFAS arise that we don’t yet know about. However, the researchers doing the non-targeted analysis are developing and using methods with more sensitive instrumentation that we can adapt to routine analysis if needed. As new compounds become suspects, there will be a need to create new standard isotopes that can be used for routine detection and quantitation.

Q: What are the first couple steps to creating standards and methods development for PFAS detection in foods and food packaging?
A: Foods and food packaging are already being analyzed for organic contaminants, what is done for newer compounds like PFAS are spiking samples and measuring the amounts after spiking experiments. This tells you the % efficiency of your extraction and analysis. These spiking experiments with select standards can be done in any food matrix or packing material.

In summary, the need for analysis of PFAS in foods and food packaging should be done in conjunction with toxicology experiments. This approach for PFAS and PFAS mixes are really the best way to provide for efficient food safety.

About the expert
Richard Jack, Ph.D., is the Global Market Development Manager for the Food, Cannabis and Environmental Markets at Phenomenex. Richard has nearly two decades of experience in product and market development in the analytical sciences industry, including as a former EPA Scientific Advisor developing validated methods through new applications, instrumentation, column chemistries, and software. Richard received his M.S. in Ecology from the Univ. of TN, Knoxville, TN. and his Ph.D. in Biochemistry and Anaerobic Microbiology from VA Tech in Blacksburg, VA.