Another Study Was Just Published on Pet Food. This Time, It’s About Plastic

Plastic pollution tends to bring certain images to mind: ocean debris, a stray grocery bag caught on a fence, a discarded water bottle. Most pet parents do not think to add a bag of kibble or a can of wet food to that list. A recent study out of the University of Sussex and the University of Exeter suggests maybe they should, because plastic has become so woven into modern food production and packaging that it is turning up in places nobody was really looking.

What Are Microplastics, and Why Look at Pet Food?

Microplastics are tiny plastic fragments, generally smaller than five millimeters, that come from the breakdown of larger plastic items or from materials used directly in manufacturing and packaging. They have already been documented in human food, drinking water, and the air. Pet food has not been studied nearly as closely, which is part of what makes this research notable. Pets often eat a narrower, more repetitive diet than people do, frequently from the same handful of products for years at a time, so understanding their exposure matters in its own right.

Inside the Study

The full study is published in Environmental Toxicology and Chemistry (volume 45, issue 8, 2026) and can be read at academic.oup.com/etc/article/45/8/2182/8692434.

Researchers tested 228 samples drawn from 38 commercial pet food products sold in the United Kingdom, spanning 14 cat foods, 16 dog foods, and 8 hedgehog foods across different price tiers. Each product was tested in six replicates using a combination of chemical digestion and Fourier Transform Infrared Spectroscopy, a method that allows scientists to confirm not just that plastic is present, but what type of plastic it is.

What the Researchers Found

The results were more widespread than many would expect. Microplastics were detected in 27.6 percent of the individual samples tested, but when the researchers looked at whether a product had turned up positive in at least one of its six replicates, that number jumped to 76.3 percent of products. Looking at brands as a whole, 84.2 percent showed contamination in at least one product somewhere in their lineup.

The types of plastic identified were telling. The most common were polyester, polyacrylamide, polypropylene, and polyethylene, materials generally associated with textiles, industrial processing equipment, and packaging rather than the meat, grain, or vegetable ingredients that make up the food itself. That distinction matters for how pet parents think about this issue. It points less toward a single ingredient to avoid and more toward the broader production and packaging chain.

Two other patterns stood out. Budget priced products carried meaningfully higher microplastic concentrations than premium options, a real and statistically significant difference worth understanding rather than just noting. Dry food also had a higher concentration of plastic per gram than wet food, but because pets typically eat a larger volume of wet food to meet their energy needs, total daily exposure was often higher from wet food despite its lower concentration. In practical terms, a large dog eating a typical diet could realistically ingest somewhere between 162 and 2,314 microplastic particles a day.

What This Study Does Not Tell Us

The researchers themselves were candid that the exact source of the contamination is still unclear and needs further investigation. They were equally candid that while microplastics have been shown to disrupt organ function and fertility in laboratory studies involving other species, specific health consequences for dogs and cats have not yet been established. This doesn't mean they are not affected, it just means that there have not been any studies performed. This study also focused on commercial dry and wet products, not raw or home prepared diets, more on what that means below.

Why Would Cheaper Products Have More Plastic If It Isn’t About the Ingredients?

The plastics identified were mostly tied to industrial processing equipment, packaging, and textiles, not the food itself. But budget products tend to rely more heavily on vague, catch all ingredients like meat and animal derivatives rather than a named cut, and turning those lower grade, more processed inputs into a finished product usually means more contact with industrial equipment and packaging along the way. Price itself is likely a marker for how much processing and packaging a product went through to reach the shelf, not a direct cause on its own.

That same logic is useful for thinking about commercial raw versus home cooked diets, since this study tested neither directly. A commercial raw diet is still manufactured and sealed in plastic, so it is not automatically clean just because the protein is not cooked. But because raw diets typically use named, whole ingredients rather than derivative wording, and go through fewer processing steps than extruded kibble, it is reasonable to expect a quality commercial raw product sits closer to a well made premium food than to a budget bag of kibble or a cheap can. That is a reasoned extension of what this study found, not something tested directly, so it is worth treating as a plausible expectation rather than a proven result.

Home cooking with self sourced ingredients goes further still, cutting out the manufacturing step entirely: no factory processing line, no plastic sealed at a facility, a shorter chain from source to bowl. That is likely the lowest exposure option of the three, though not zero. A 2024 study on human proteins (Milne et al.) found microplastics fairly evenly across meat, seafood, and plant sources regardless of processing, so some contamination is likely environmental, and everyday touchpoints like a plastic cutting board or meat wrapped in film at the counter still matter. A 2025 review of food packaging research (Zimmermann et al.) found microplastics in over 96 percent of the packaging and food contact materials studied, which is the evidence behind the packaging concern in the first place.

The practical takeaway: sourcing named, minimally processed ingredients, whether that means a well made commercial product or a known butcher, and storing food in glass or stainless steel rather than plastic, are reasonable steps regardless of feeding style. Home cooked is likely the lowest exposure option, a quality commercial raw diet is likely closer to a premium food than to a budget one, and none of the three should be treated as guaranteed plastic free.

What This Means for Everyday Pet Parents

A few practical, defensible takeaways translate regardless of what a pet currently eats:

1. Price is a reasonable rough guide, not a guarantee. Premium products trended cleaner, but were not contamination free.

2. Named, specific ingredients trended lower risk than vague, derivative style wording, regardless of price tier.

3. Storing dry food in its original bag, or in a sealed container rather than loose in a bin, may help limit additional plastic shedding from repeated handling and scooping, though this specific behavior was not directly tested in the study.

4. Rotating between a few trusted products rather than relying on a single item for years may reduce cumulative exposure to any one contamination source, the same logic that applies to many nutrition recommendations already.

5. It is entirely reasonable to ask a pet food manufacturer whether they test for microplastics and what steps they take during processing and packaging to limit contamination.
   

When to Talk to a Veterinarian

Because pet specific health effects have not yet been established, there is no current official recommendation to change a pet’s diet solely because of this study. Pet parents who want to discuss overall diet quality, ingredient sourcing, or general nutrition planning are always welcome to bring those questions to their veterinarian, who can offer guidance based on an individual pet’s health history and needs.

The Bottom Line

Microplastics showed up in the large majority of pet food products tested in this study, which is worth knowing, but the researchers were honest that pet specific health risks are not yet established and that the source of contamination is still being investigated. That combination, real findings paired with real scientific humility, is exactly the kind of information pet parents deserve: not a headline designed to alarm, but a clear picture of where the evidence stands today and what questions are worth asking as more research comes in.

Frequently Asked Questions

What are microplastics, and how do they end up in pet food? Microplastics are tiny plastic particles, generally under five millimeters, that can come from packaging materials, processing equipment, or the broader environment. Researchers are still working to pin down exactly which of these sources contributes most to pet food contamination.

Are microplastics dangerous for dogs and cats? Pet specific health effects have not yet been established. Laboratory research in other species has linked microplastic exposure to disrupted organ function and fertility, but researchers have been clear that more pet focused study is needed before drawing firm conclusions.

Does premium pet food contain fewer microplastics than budget options? Generally yes, though not perfectly. Budget priced products in this study showed meaningfully higher concentrations on average, likely because they involve more industrial processing and more use of vague, derivative style ingredients rather than because cheaper ingredients are inherently dirtier. Premium products were not free of contamination either.

Is wet food or dry food more likely to expose a pet to microplastics? Dry food had a higher concentration of plastic per gram, but because pets eat larger volumes of wet food to meet their nutritional needs, total daily exposure was often higher from wet food.

What can pet parents do to reduce their pet’s exposure to microplastics? Storing food properly, rotating between a few trusted products, and asking manufacturers about their testing and packaging practices are all reasonable, low effort steps. None of these require an immediate diet change, since the current evidence does not point to one.

Does feeding a fresh or raw diet reduce microplastic exposure? It likely depends more on quality and processing than on raw versus cooked by itself. A commercial raw diet is still manufactured and packaged, so it is reasonable to expect a quality one sits closer to a premium commercial food than to budget kibble, not automatically clean just because it is raw. Home cooking with self sourced ingredients likely reduces exposure the most, though not to zero, since some contamination comes from the environment itself.

None of this is meant to scare anyone. Plastic is simply part of modern life, food packaging included. The point of sharing research like this is to make good information available, not to create fear. The more pet parents understand, the better equipped they are to make calm, informed decisions for their own pets. Dr Paris Asghari, DVM