A study conducted by researchers from the University of Exeter and the University of Sussex has found that a significant majority of popular pet foods in the UK contain microplastic particles. Testing of 38 products from 19 major brands revealed that 76 percent of foods for cats, dogs, and hedgehogs were contaminated.
Tesco's Chunks In Jelly Tinned Dog Food was found to have the highest concentration of microplastics per gram among wet dog foods, with up to three particles per gram, more than double the average of 1.42 particles per gram found in contaminated wet food. Researchers estimate that a large dog could consume up to 2,314 microplastic particles daily from such food.
Microplastics were detected in at least one sample for 84 percent of all pet food brands tested, and 47 percent of products showed contamination in at least two of the six samples. Three specific products—Waitrose Essential Meaty Chunky in Jelly with Chicken cat food, Waitrose Complete and Balanced Dog Food Chicken and Vegetable, and Whiskas Chicken in Jelly—had microplastics in five out of six samples.
Concerns Over 'Animal Derivatives'
Researchers noted a higher prevalence of microplastic contamination in products containing "animal derivatives," which are ingredients not considered suitable for human consumption used to increase bulk. "Of these products with animal derivatives, 90 percent had microplastic contamination," stated co-author Professor Fiona Matthews of the University of Sussex.
Cat food contamination levels also varied, with Lily's Kitchen 'Chicken with Tasty Veggies' dry food showing the highest concentration at three microplastic particles per gram. While dry foods sometimes had higher concentrations, wet foods pose a greater risk due to the larger quantities pets consume. Whiskas wet cat food, with up to two particles per gram, is considered a significant source of daily plastic ingestion for cats, who eat approximately five times more wet food by weight than dry food.
Potential Health and Environmental Impacts
Experts are increasingly concerned about the potential negative health consequences of microplastic consumption for both pets and humans. Scientists warn that these particles can accumulate fat-soluble chemicals like pesticides and hormones, acting as carriers of toxins that can pass through the body. There is growing evidence suggesting plastics may play a role in cancer development, with a 2024 study indicating that microplastics can accelerate the spread of cancer cells in the gut.
"We are even finding that small particles can travel across the gut barrier and make their way into organs," Professor Matthews commented. "This is worrying because, as well as potentially causing physical problems, we know that microplastics can accumulate fat-soluble chemicals, such as pesticides and hormones, so they can act as a 'bullet' of toxins."
Beyond direct consumption, experts are concerned that microplastics excreted by pets could contaminate terrestrial ecosystems. Lead author Emily Thrift highlighted that the large number of pets in the UK, along with wildlife supplementing their diets with pet food, represents a significant and previously unrecognized pathway for plastic to enter the environment.
Researchers are still investigating the source of this plastic contamination, with potential links to ingredient sourcing, packaging, or processing methods. The study did not find a strong correlation between higher-priced pet foods and reduced plastic contamination.
In response, a spokesperson for UK Pet Food, the industry body, stated that their members' products comply with all applicable regulations and food safety standards, assuring pet owners they can continue feeding commercially prepared pet food with confidence. The organization indicated it continues to engage with regulators and scientists to consider new research.