Microplastic contamination has been reported in beef and pork for the first time, as well as in the blood of cows and pigs on farms.

Scientists at the Vrije Universiteit Amsterdam (VUA) in the Netherlands found the particles in three-quarters of meat and milk products tested and every blood sample in their pilot study.

They were also found in every sample of animal pellet feed tested, indicating a potentially important route of contamination. The food products were packaged in plastic, which is another possible route.

VUA researchers reported microplastics in human blood for the first time in March, and they used the same methods to test the animal products. The discovery of the particles in blood shows they can travel around the body and may lodge in organs.

The impact on human or farm animal health is as yet unknown, but researchers are concerned because microplastics cause damage to human cells in the laboratory and air pollution particles are already known to enter the body and cause millions of early deaths a year. Some wildlife is also known to be harmed by microplastics.

Huge amounts of plastic waste are dumped in the environment, and microplastics have contaminated the entire planet, from the summit of Mount Everest to the deepest oceans. People were already known to consume the tiny particles via food and water as well as breathing them in.

“When you’re measuring blood, you’re finding out the absorbed dose from all the different exposure routes: air, water, food, et cetera,” said Dr Heather Leslie at VUA. “So it’s very interesting because it immediately tells you what’s penetrating into the river of life.”

The pilot study was conducted to assess whether microplastics are present in farm animals, meat and dairy. “It should act as an impetus to further explore the full scope of exposure and any risks that may be associated with it,” said Leslie.

The scientists tested 12 samples of cows’ blood and 12 of pigs’ blood and found microplastics in all of them, including polyethylene and polystyrene. The 25 milk samples included milk from supermarket cartons, milk tanks on farms and hand-milking. Eighteen of the samples, including at least one of each type, contained microplastics.

Seven of the eight beef samples and five of the eight pork samples were contaminated. “It remains unknown if there are any potential toxicological risks of these findings,” the report said. Farm animals and meat have yet to be tested in other countries, but microplastics were reported in purchased milk in Switzerland in 2021 and farm milk in France.

Maria Westerbos at the Plastic Soup Foundation, which commissioned the research, said: “With microplastics present in livestock feed, it is not surprising that a clear majority of the meat and dairy products tested contained microplastics. We urgently need to rid the world of plastic in animal feed to protect the health of livestock and humans.”