Ripping the plastic wrap from the meat or prepackaged fruit and veggies you purchased at the grocery store may contaminate your food with micro- and nanoplastics, according to new research.

Plastic contamination may also occur when you’re unwrapping deli meat and cheese, steeping a tea bag in hot water, or opening cartons of milk or orange juice. Glass bottles and jars with a plastic-coated metal closure may also shed microscopic bits of plastic, the study found.

In fact, the abrasion from repeatedly opening and closing the caps on glass and plastic bottles can release an untold amount of micro- and nanoplastics into the beverage, said Lisa Zimmermann, lead author of the study published Tuesday in the journal NPJ Science of Food.

“The research shows the number of microplastics increases with each bottle opening, so therefore we can say it’s the usage of the food contact article which leads to micro- and nanoplastic release,” said Zimmermann, scientific communication officer at the Food Packaging Forum, a nonprofit foundation based in Zurich, Switzerland, that studies chemicals in food contact materials.

Researchers have measured micro- and nanoplastics in such food and drink products as beer, canned fish, rice, mineral water, tea bags, table salts, take-out foods and soft drinks, according to the study.

“This is the first systematic evidence of how normal and intended use of foodstuffs packaged in plastics can be contaminated with micro- and nanoplastics,” Zimmermann said. “We found food packaging is actually a direct source of the micro- and nanoplastics measured in food.”

A separate investigation by the Food Packaging Forum published in September 2024 found more than 3,600 chemicals leach into consumer products during food manufacturing, processing, packaging and storage, ending up in the human body.

Seventy-nine of those food-processing chemicals are known to cause cancer, genetic mutations, endocrine and reproductive issues, and other health concerns, according to the September 2024 study.

And while scientists have long known about potentially toxic chemicals from plastics leaching into food, “what’s less clear, and deeply concerning, is just how significant food packaging is as a source of exposure to plastic particles and what that means for our health,” said David Andrews, acting chief science officer at the Environmental Working Group, a Washington, DC-based health and environmental advocacy organization, in an email.

“This new study highlights food packaging and processing equipment as potentially significant sources of microplastic contamination in the food we eat, and ultimately in our bodies,” said Andrews, who was not involved with the research. “This study should raise alarm bells.”

CNN reached out to the Plastics Industry Association for comment but did not hear back before publication.

What are micro- and nanoplastics?

Microplastics are polymer fragments that can range from less than 0.2 inch (5 millimeters) down to 1/25,000th of an inch (1 micrometer). Anything smaller is a nanoplastic that must be measured in billionths of a meter.

At 1,000th the average width of a human hair, experts say nanoplastics are so teeny they can migrate through the tissues of the digestive tract or lungs into the bloodstream. As the blood circulates, the plastics may distribute potentially harmful synthetic chemicals throughout the body and into cells.

A flurry of recent studies have discovered microplastics and nanoplastics in human brain tissue, the testes and the penis, human blood, lung and liver tissues, urine and feces, mother’s milk, and the placenta.

In the first analysis to illustrate harm to human health, a March 2024 study found people with microplastics or nanoplastics in their carotid artery tissues were twice as likely to have a heart attack or stroke or die from any cause over the next three years than people who had none.

The latest research searched thousands of studies to find those that did the best job of identifying and measuring plastics in tested foods before narrowing the list to 103 for the review.

Microplastic research is quite new, and studies so far often use different methods of microplastic identification and measurement. The lack of standard protocol can make it difficult to adequately compare findings, said senior study author Jane Muncke, managing director and chief scientific officer at the Food Packaging Forum.

“The novel aspect of our analysis is we didn’t just collect all the studies, but we also examined the scientific reliability of their methods. We included a critical appraisal step,” Muncke said. “That left us with seven highly reliable studies — more high-quality research is definitely needed.”

According to that research, ultraprocessed foods contain significantly more microplastics than minimally processed foods.

“There’s a higher number of manufacturing steps with ultraprocessed foods, which can increase the contact time with plastic food processing equipment,” Muncke said, “thus increasing the chance of micro- and nanoplastic migration.”

Migration into food also increased when the plastic packaging was heated, washed for reuse, exposed to sunlight and subjected to mechanical stress — such as the twist used to open a bottle cap, according to the review. That sort of repeated stress could lead to higher abrasion than opening a plastic container, so future research should consider how plastic is used as well as the types of plastics, Muncke said.

“This is a rigorous, detailed and critical study that applies robust systematic methods to review the existing literature on microplastics and food contact materials,” said Megan Deeney, a research fellow and doctoral student in plastics and global health at the London School of Hygiene & Tropical Medicine at the University of London, in an email.

“What is particularly important is that the authors take the time to extract and evaluate evidence on whether the presence of microplastics changed over time in these studies — this can help to identify the food contact material itself as a direct source of food contamination by microplastics,” said Deeney, who was not involved with the new research.

One of the studies included in the new review found 1 liter of water — the equivalent of two standard-size bottled waters bought at the store — contained an average of 240,000 plastic particles from seven types of plastics, of which 90% were identified as nanoplastics and the rest were microplastics.

Another example involved melamine, which is used to make bowls, plates, cups and other plastic tableware.

“In one study, researchers washed a melamine bowl 10 times, 20 times, 50 times, 100 times and measured the amount of microplastic it released each time,” Zimmermann said. “Then they put something in the bowl and tested it and found more microplastic release after increased washing.”

While it’s not yet possible to clean microplastics from the food supply, there are steps one can take to reduce exposure to plastics and the chemicals they secrete.

“One is to reduce our plastic footprint by using stainless steel and glass containers, when possible,” said Dr. Leonardo Trasande, director of environmental pediatrics at NYU Langone Health, in an earlier interview with CNN.

“Avoid microwaving food or beverages in plastic, including infant formula and pumped human milk, and don’t put plastic in the dishwasher, because the heat can cause chemicals to leach out,” Trasande said.

In addition, check the recycling code on the bottom of packaging to find the plastic type, and avoid plastics with recycling code 3, which typically contain phthalates, he added.

Bring reusable bags to the grocery store, suggests the Natural Resources Defense Council, a New York City-based environmental advocacy group. Invest in a zippered fabric bag and ask the dry cleaner to return your clothes in that instead of those thin sheets of plastic. Bring a travel mug to the local coffee store for takeout and silverware to the office, cutting back on plastic cups and utensils.

However, due to the pervasiveness of microplastics in the environment, “this is not something that any individual can solve on their own,” Deeney said.

“We need systemic action to reduce plastics production and pollution,” she said via email, encouraging anyone concerned about the issue to send a message to their representatives.

“There’s a critical opportunity for individuals to engage with governments to demand strong, ambitious action on plastics in the upcoming final round of negotiations for a Global Plastics Treaty in Geneva this August, where more than 175 countries will convene to determine a legally-binding instrument to end plastics pollution.”

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