Read the full article by Karen Steward PhD (Technology Networks)
“You may be familiar with the concept of food contamination caused by chemicals from food packaging. But did you know that these same chemicals can enter the food chain well before that burger has even been made, let alone cooked or served? The dangers of per- and polyfluoroalkyl substances (PFAS) have been repeatedly highlighted in recent years, but detecting their presence, let alone preventing the many routes of ingress into our food chain, is a challenge.
We spoke to Dr Katherine C. Hyland, Applications Specialist, Environmental, Food and Beverage at SCIEX, about the many routes by which PFAS enter the food chain, the problems they cause and why they can be such a headache for analysts.
Karen Steward (KS): How do PFAS get into our food and why are they such a problem?
Katherine Hyland (KH): There are a few major routes by which PFAS can enter our foods and food supply. The three which have been most concerning and most studied to date include:
· Leaching from treated food packaging materials
· Bioaccumulation in food organisms high in the trophic chain
· Accumulation in produce treated with contaminated water or biosolids-amended soils
Of these, it seems that leaching from food packaging has received the most significant media attention and studied.1 PFAS are used in food packaging that needs to resist saturation by oils and water (such as steam). Common examples include paper wrappers like those for burgers and sandwiches, paperboards like pizza boxes or french fry holders, microwave popcorn bags, paper cups and more.
What’s noteworthy about PFAS in food contact materials (FCMs) is that they encompass a range of chemical classes. Besides the common C8 carboxylate and sulfonate species perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), chemicals used for FCMs include fluorotelomer alcohols (FTOHs), polyfluoroalkyl phosphate esters (PAPs), as well as other chain lengths of the carboxylates and sulfonates.2
So, when we consider entry of PFAS by accidental consumption due to food contact, we actually must think about a wider range of chemical constituents than is typically considered for environmental samples. For instance, Europe adopted the Commission Recommendation 2010/161/EU to monitor PFAS in food but it is primarily on the commonly known PFAS—PFOS and PFOA.3 Similarly, the established PFAS health advisory guideline in the United States, EPA Method 537.1, is focused on water and only mentions PFOS and PFOA.4 That said, the United States Food and Drug Administration (FDA) recently developed studies to quantify PFAS in food.5 Nevertheless, substances such as FTOHs and PAPs are absent from these guidelines.
Bioaccumulation to higher trophic levels has been primarily observed/studied in marine systems. The cycle usually resembles PFAS entering water systems, contaminating low-level organisms like amphipods. These organisms are eaten by smaller fish, which are then consumed by larger fish and mammals. Studies have found positive correlations between the serum concentrations of long-chain PFAS in people, and the seafood consumption of the community.6,7 This is particularly interesting as while “legacy” contaminants like PCBs and PBDEs also bioaccumulate up the food chain, the mechanisms by which those happen are different from PFAS. Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), for example, accumulate in fatty tissues. While the accumulation behavior of long-chain PFAS mimics that of these highly nonpolar legacy species, PFAS does not accumulate in fatty tissues. Their unique chemical properties make it more difficult to predict the partitioning behavior of PFAS in animal organisms.
Fruits and vegetables can also bioaccumulate PFAS when they are irrigated with PFAS-contaminated water. While this may seem intuitive, there is a plot twist—it is the shorter chain PFAS that are preferentially taken up by food crops from contaminated water…”