Exposure of U.S. adults to microplastics from commonly-consumed proteins

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Scientists find almost 90% of protein sources from supermarkets contain microplastics. Samples were taken from 16 different proteins sold in the U.S., including seafood, pork, beef, chicken, tofu, and three different plant-based meat alternatives.

“This is a startling reminder of just how prolific plastic pollution has become – humans live on land and yet seafood samples are just as likely to be contaminated with plastics as are terrestrial derived proteins,” said study co-author Dr. Britta Baechler, a marine biologist and Associate Director of Plastics Science at Ocean Conservancy. “And there’s no escaping them no matter what you eat, it seems. The plastic pollution crisis is impacting all of us, and we need to take action to address its many forms.”

Abstract: We investigated microplastic (MP) contamination in 16 commonly-consumed protein products (seafoods, terrestrial meats, and plant-based proteins) purchased in the United States (U.S.) with different levels of processing (unprocessed, minimally-processed, and highly-processed), brands (1 – 4 per product type, depending on availability) and store types (conventional supermarket and grocer featuring mostly natural/organic products). Mean (±stdev) MP contamination per serving among the products was 74 ± 220 particles (ranging from 2 ± 2 particles in chicken breast to 370 ± 580 in breaded shrimp). Concentrations (MPs/g tissue) differed between processing levels, with highly-processed products containing significantly more MPs than minimally-processed products (p = 0.0049). There were no significant differences among the same product from different brands or store types. Integrating these results with protein consumption data from the American public, we estimate that the mean annual exposure of adults to MPs in these proteins is 11,000 ± 29,000 particles, with a maximum estimated exposure of 3.8 million MPs/year. These findings further inform estimations of human exposure to MPs, particularly from proteins which are important dietary staples in the U.S. Subsequent research should investigate additional drivers of MPs in the human diet, including other understudied food groups sourced from both within and outside the U.S.

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