Researchers in Spain discovered microplastics—tiny plastic particles invisible to the naked eye—in all five brands of commercial dry pet food they tested. Dog food contained 9.33 plastic particles per 5 grams, more than twice the 4.07 particles found in cat food. According to Gram Research analysis, these plastics likely come from environmental pollution, food processing, and packaging materials. While the study is preliminary and doesn’t yet prove these microplastics harm pets, it raises concerns about long-term exposure through daily feeding.
Researchers in Spain discovered tiny plastic particles in commercial dry pet food for the first time. They tested five popular pet food brands and found microplastics—pieces of plastic smaller than a grain of sand—in every single sample. Dog food contained more than twice as many plastic particles as cat food. The study suggests these plastics come from the environment, food processing, and packaging materials. While the long-term health effects on pets aren’t completely clear yet, the findings raise concerns about whether pets eating this food could experience health problems over time.
Key Statistics
A 2026 exploratory study of five pet food brands in Spain found microplastics in 100% of dry dog and cat food samples tested, with dog food containing 9.33 microplastic particles per 5 grams compared to 4.07 particles in cat food.
Researchers identified six types of plastics in pet food including PET (plastic bottles), polyethylene (plastic bags), polypropylene (food containers), polyamide (fishing nets), ethylene-vinyl acetate (shoe soles), and polystyrene (foam packaging).
According to a 2026 Spanish study, dog food contained over twice as many microplastics as cat food (9.33 ± 0.41 MPs/5g vs. 4.07 ± 0.68 MPs/5g), suggesting dogs may face greater health risks from microplastic consumption.
The Quick Take
- What they studied: Whether tiny plastic particles (smaller than a sesame seed) are present in the dry pet food that millions of pets eat every day
- Who participated: Five different brands of commercially available dry pet food sold in Spain, tested using advanced microscopy equipment
- Key finding: All five pet food brands contained microplastics. Dog food had 9.33 plastic particles per 5 grams, while cat food had 4.07 particles per 5 grams—more than twice as much in dog food
- What it means for you: Pet owners should be aware that microplastics in pet food may be a concern, though more research is needed to understand the actual health impact on dogs and cats. This is an emerging issue worth monitoring as scientists learn more
The Research Details
This was an exploratory study, meaning it was designed to investigate a problem that hasn’t been studied much before. Researchers purchased five different brands of dry pet food from Spanish stores and analyzed them using three different high-powered microscopy techniques. These tools allowed scientists to see and identify tiny plastic particles that are invisible to the naked eye. The researchers counted how many plastic pieces were in each food sample and identified what types of plastics they were—similar to how a detective might examine evidence at a crime scene using different tools to get complete information.
This is the first study to look specifically at microplastics in pet food, so it fills an important gap in our knowledge. Since pets eat the same food every single day, understanding what’s in that food matters for their health. The study also helps us understand how microplastics move through our environment and food systems, which affects both animals and humans.
This was a small exploratory study with only five food brands tested, so the results are preliminary. The researchers used reliable scientific equipment and methods, which is good. However, because this is the first study of its kind, the findings need to be confirmed by other scientists testing more brands and larger quantities. The study doesn’t tell us whether the amounts of plastic found actually cause health problems in real pets.
What the Results Show
Every single pet food brand tested contained microplastics. The study identified six different types of plastics: PET (used in plastic bottles), polyethylene (plastic bags), polypropylene (food containers), polyamide (fishing nets and textiles), ethylene-vinyl acetate (shoe soles), and polystyrene (foam packaging). Dog food contained significantly more plastic particles than cat food—about 2.3 times more. The researchers believe the plastics come from three main sources: the environment (from pollution), the food processing machinery and facilities, and the packaging materials used to store and transport the food. The study suggests that dogs may be at higher risk for systemic health effects from these plastics, while cats might be more vulnerable to chronic intestinal inflammation because of how the plastic fibers accumulate in their digestive systems.
The research created a risk assessment model that considered how sensitive each species is to plastic damage, the size of the plastic particles (smaller ones are potentially more dangerous), and how much food each pet eats daily. This model showed that dogs face greater overall health risks than cats based on the amount of microplastics they consume. The study also highlighted that pets could serve as ‘indicator animals’—meaning by studying what’s in pet food, we learn about microplastic contamination in our broader food and environment.
This is the first study to examine microplastics specifically in pet food, so there’s no previous research to directly compare it to. However, other studies have found microplastics in human foods like seafood, drinking water, and salt. This new research suggests that microplastic contamination in food is a widespread problem affecting both humans and pets.
The study only tested five pet food brands from Spain, so we don’t know if these results apply to pet foods in other countries or to brands not included in the study. The sample size is very small for drawing broad conclusions. The study doesn’t include actual health data from pets eating this food—it’s based on calculations and risk models rather than observing real animals. We also don’t know the long-term health effects of eating these microplastics, so the actual danger to pets remains unclear. More research with larger samples and longer-term health monitoring is needed.
The Bottom Line
Pet owners should be aware of this emerging concern but don’t need to panic based on this single study. According to Gram Research analysis, the evidence is preliminary and more research is needed before making major changes to pet diets. If you’re concerned, consider discussing pet food options with your veterinarian. Look for brands that use minimal plastic packaging, though this won’t eliminate microplastics from the food itself. Monitor your pet’s health and report any digestive issues to your vet. Confidence level: Low to Moderate (this is early-stage research).
All pet owners should be aware of this research, particularly those with dogs, who appear to consume more microplastics than cats. Pet food manufacturers should care about this finding and work to reduce plastic contamination in their products. Veterinarians should stay informed about this emerging issue. Environmental advocates should recognize that microplastic pollution affects the entire food chain, including pet food.
Because this is the first study and the long-term health effects are unknown, we can’t predict a timeline for seeing health impacts. It may take years of additional research to understand whether the microplastics found in pet food actually cause health problems in real animals. Pet owners should expect more research on this topic over the next few years.
Frequently Asked Questions
Is microplastic in pet food dangerous to my dog or cat?
The study found microplastics in all pet food tested, but long-term health effects aren’t yet proven. Dogs appear more vulnerable than cats based on consumption amounts. More research is needed to determine actual health risks. Discuss concerns with your veterinarian.
How do microplastics get into pet food?
Microplastics enter pet food from three sources: environmental pollution in ingredients, food processing machinery and facilities, and packaging materials. The plastics break down into tiny particles that contaminate the final product.
Can I reduce microplastics in my pet’s diet?
While this study doesn’t provide specific solutions, choosing pet foods with minimal plastic packaging and discussing alternatives with your veterinarian may help. However, microplastics may still be present regardless of packaging since they come from multiple sources.
Should I switch my pet’s food because of this study?
This is the first study on this topic, so evidence is preliminary. Before making changes, consult your veterinarian. Switching foods suddenly can upset pets’ digestive systems, so any changes should be gradual and discussed with your vet first.
Do humans also eat microplastics in their food?
Yes, microplastics have been found in human foods like seafood, drinking water, and salt. This study shows the problem extends to pet food, suggesting microplastic contamination is widespread throughout the food system affecting both animals and people.
Want to Apply This Research?
- Track your pet’s current food brand and the date you started monitoring. Record any digestive changes (vomiting, diarrhea, constipation, or appetite changes) weekly in the app to establish a baseline before any dietary changes.
- Research and document alternative pet food brands in the app, noting their packaging materials and sourcing information. Use the app to compare brands and set reminders to discuss microplastic concerns with your veterinarian at the next checkup.
- Set monthly reminders to review your pet’s digestive health and energy levels. Track any changes in weight, coat quality, or digestive symptoms. Use the app to maintain a long-term health log that you can share with your veterinarian to identify patterns or concerns related to diet.
This article summarizes preliminary research on microplastics in pet food. The findings are from a small exploratory study and have not yet been confirmed by other researchers. The long-term health effects of microplastics on pets are not yet established. This information is for educational purposes only and should not replace professional veterinary advice. If you have concerns about your pet’s health or diet, consult your veterinarian before making any changes to your pet’s food or feeding practices. Do not use this article to diagnose or treat any health condition in your pet.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.