Presence and contamination of meat with perfluoroalkyl (PFAS) compounds

Perfluoroethyl compounds (PFAS) is a collective term for a very large group of fluorinated compounds, including oligomers and polymers, consisting of neutral and anion surface active compounds with high heat, chemical and biological inertness. Perfluorinated compounds are generally hydrophobic but also lipophobic and therefore will not accumulate in fat tissues as is usually the case with other persistent halogenated compounds. An important subgroup are (per) fluorinated organic surfactants, including perfluorooctane sulfonate (PFOS) and perfluorooctane acid (PFOA). For PFOS and PFOA, the European Food Safety Authority (EFSA) established a tolerable daily intake (TDI) for humans of 150 ng/kg body weight and 1.5 μg/kg body weight per day (EFSA 2008).

PFAS are best described as a homologous series of fully fluorinated carboxylic acids, which may also be present as sulfonic acids or sulphonamide derivatives. Different compounds of higher molecular weight from which these persistent contaminants are believed to originate should also be considered. The actual list of PFAS requiring monitoring as contaminants or source pollutants consists of 200 individual compounds. Measuring all possible PFAS at this point is unrealistic. The list of priority analogues is generally limited to simple carboxylic acids, sulfonic acids and amides.

Per - and polyfluorocellular compounds have been produced and used since the 1940 s and although many PFAS have been withdrawn from the manufacturing industry, they are still in drinking water and consumer goods such as food packaging, carpets, leather, textiles and non-alcoholic dishes. The release of PFAS into the environment has become globally worrisome. Since PFAS rarely decompose in the environment, they can be kept in water and air for thousands of years, which is why they have been nicknamed “eternal chemicals”. Their consumption or inhalation means they could stay in the body for life.

In addition to cancer connection, PFAS has been associated with hepatic impairment and developmental problems.

In response, many agencies worldwide study the impact of PFAS on food. The livestock may potentially be exposed to PFAS by consumption of contaminated surface water, groundwater, pastureland or soil. The most recent report published by the European Food Safety Authority (EFSA) in 2020 found that fish, meat, fruit/fruit products and eggs/egg products mostly contribute to human exposure to PFAS through nutrition during the 2007-2018 survey period (Schrenk et al., 2020). From this study, EFSA set a recommended tolerable weekly intake (TWI) of 4.4 ng per kg body weight for a total of 4 PFAS: PFOA, PFNA, PFHxS and PFOS.

Among food of animal origin, the EFSA study showed that THE mean identified concentration of PFAS varies depending on the type of sample. PFOA, PFNA, PFHxS and PFOS were found in animal and game meat ranging from 0,02-1,59 ng/g, in edible farmed offal ranging from 0,087-1,18 ng/g, in salmon and trout ranging from 0,003-0,83 ng/g, and in eggs and egg products ranging from 0,06-0,35 ng/g. The mean concentration detected in all sample types considered was 0.32 ng/g. In addition to the EFSA study, the FDA monitors contaminants, including PFAS, in highly consumed foods in its study “Total diet study” (TDS) (FDA, 2021). In the latest 2019 study, the TDS reported a finding of 0.087 ng/g of PFOS in Tilapia.

There is no maximum level for PFAS in feed derived from livestock. However, since these chemicals have remained in humans and the environment for many years, it is recommended that people's exposure to PFAS be minimised as a precautionary measure wherever possible. No country has set regulatory limits for PFAS in food. The European Commission commits to phasing out all PFAS, allowing them to be used only where they are proven irreplaceable and relevant for society. The recast of the drinking water Directive, which entered into force on 12 January 2021, includes a limit of 0,5 µg/L for all PFAS.

Literature:

1. Schrenk D., M. Bignami (2020): EFSA Panel on Contaminants in the Food Chain (EFSA CONTAM Panel), Risk to Human Health Related to the Presence of Perfluoroalkyl Substances in Food, DOI: 10.2903/sp.efsa.2020.EN-1931.

2. Food and Drug Administration. Analytical Results of Testing Food for Pfas From Environmental Contamination. June 2021. https://www.fda.gov/food/chemical-contaminants-food/analytical-results-testing-food-pfas-environmental-contamination.