Better Understanding of Chemicals Used To Grease-Proof Food Packaging Needed
Chemicals used to “grease proof” everything from food packaging to carpets have built up in the environment for decades and contaminate ecosystems across the globe, and a new study is calling for a better understanding of the risks posed by these chemicals.
The study, published in the academic journal Trends in Food Science & Technology, collects the proceedings of a symposium chaired by an Iowa State University scientist and issued a call to action on the need for new and better ways to detect and mitigate this class of chemical compounds, collectively known as per- and polyfluoroalkyl substances (PFAS). Evidence indicates exposure to high levels can lead to adverse health effects for humans and other species, and the study stresses the need for new ways to measure and study exposures to these synthetic chemicals from various sources including food.
PFAS accumulate in the environment and do not break down on their own. For instance, the compounds can contaminate waterways after leaching from products discarded in landfills, said Keith Vorst, director of the Polymer and Food Protection Consortium and an associate professor of food science and human nutrition at Iowa State. These entirely manmade chemicals have been used in a wide range of products since the 1940s, and some states have enacted legislation to restrict their use. But their ability to persist in the environment means the compounds that already exist can continue to contaminate the environment.
“They’re out there, we need to be aware of them, and it’s really hard to eliminate them,” Vorst said. “We need to work on mitigation strategies, and we need to be monitoring them and better understand the risks they pose.”
What are PFAS?
PFAS often have been used to coat food packaging as a barrier to keep grease from escaping. Vorst said paper wrappers on hamburgers are often coated in these compounds to prevent grease from leaking onto consumers’ hands. The compounds have also been used widely to coat carpets, in car interiors and in fire-fighting foams.
Some PFAS are no longer produced in the United States, but Vorst said more than 5,000 separate compounds qualify under this category, making it difficult for regulations to keep up with newly developed chemicals.
Studies have indicated that exposure to high levels of some of these chemicals can cause reproductive and developmental, liver and kidney, and immunological effects in laboratory animals, according to the Environmental Protection Agency. The EPA reports the most consistent findings are increased cholesterol levels among exposed populations, and studies have found limited evidence for links between high levels of certain PFAS and low infant birth weights, effects on the immune system, cancer and thyroid hormone disruption. (https://www.epa.gov/pfas/basic-information-pfas)
Monitoring and mitigation
The new paper emerged out of a virtual symposium held in June of 2020 organized by the Institute for the Advancement of Food and Nutrition Sciences. The symposium featured scientists, engineers and regulatory professionals from public, private and academic institutions. The symposium addressed science gaps for exposure routes, detection and quantification of PFAS in food. Speakers also noted that, based on limited data to date, there is little PFAS detected in food.
Polymer and Food Protection Consortium researchers Greg Curtzwiler, an assistant professor of food science and human nutrition, and Paulo Silva, adjunct assistant professor of food science and human nutrition, are working with Vorst in the laboratory to study potential mitigation strategies such as high voltage atmospheric cold plasma to change the chemistry of PFAS. This process could work by passing materials that contains PFAS, such as product packaging or even drinking water, through an engineered atmosphere to mitigate the compounds. The research team has tested the method and is working with Iowa State to patent the technology. Vorst’s PFPC lab has been testing new methodologies to detect and monitor PFAS levels in various environments as well. Much of this research was funded by the ISU Polymer and Food Protection Consortium.
“We’re looking at continuous monitoring of exposure limits,” Vorst said. “We’re trying to develop threshold limits for packaging and products. We’re also looking at how we can change these chemistries to get them out of the environment, make them less persistent or sequester them.”
Vorst KL et al. Risk assessment of per- and polyfluoroalkyl substances (PFAS) in food: Symposium proceedings. Trends Food Sci Technol, Volume 116, October 2021, Pages 1203-1211. doi:10.1016/j.tifs.2021.05.038
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