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.