Researchers compare kibble, air-dried, and fresh options for contaminants
-
A new independent report tested 79 popular dog foods for heavy metals and industrial chemicals.
-
Dry kibble and other processed formats were found to have much higher contaminant levels than fresh/frozen foods.
-
The study used rigorous lab methods but did not disclose individual product names.
For pet owners, its common to assume that the food youre giving your pets is safe and nutritious.
However, the Clean Label Projects Dog Food Category Report took a hard look at that assumption, aiming to see what contaminants might be hiding in commercially sold dog foods.
Rather than relying on manufacturer claims, the nonprofit organization bought and tested 79 top-selling dog foods across dry, air-dried, freeze-dried, and fresh/frozen categories to see what was in them and whether there are meaningful differences between types.
The study
Clean Label Project teamed up with an independent, ISO 17025accredited lab to analyze these products for a broad panel of industrial and environmental chemicals. They looked for things like heavy metals (arsenic, cadmium, lead, and mercury), phthalates (chemicals linked to plastics), acrylamide (a byproduct of high heat processing), and others. Over 11,000 individual data points were measured from the 79 dog foods examined.
Instead of comparing foods solely by weight or calories, the researchers focused on serving size, because thats how most pet owners actually feed their dogs. They intentionally mirrored real-world behavior like using the cup amounts shown on packaging so the results would reflect everyday exposure more realistically.
This approach doesnt identify which brands or formulas are better or worse, but it does highlight patterns across categories of food.
The results
The key takeaway from the report is that dry dog foods including traditional kibble tended to have much higher levels of contaminants compared to fresh or frozen dog food.
On average, dry foods contained significantly more arsenic, cadmium, lead, mercury, acrylamide, and phthalates than the fresh/frozen samples did, and also higher than typical human food products tested historically by the same lab.
For example, dry formats showed multiple times greater average levels of heavy metals than fresh/frozen foods. Even when accounting for serving size differences, dry foods still came out ahead in terms of contaminant concentration.
The report also suggests that ingredients like meat by-products, vitamin/mineral premixes, and certain grains or seafood might contribute to these elevated levels though it doesnt pinpoint exact sources in any individual product.
Overall, the study doesnt prove that any specific food will harm your dog, but it does raise questions about how contaminants vary across dog food types and encourages pet owners to think critically about whats in the bowl.
What pet owners can do
Before you throw out all of your dogs food, here are a few practical steps pet owners may consider:
-
Pay attention to food format. The study found that dry dog foods, on average, contained higher levels of heavy metals and certain chemicals compared to fresh or frozen formats. If youve been curious about alternative formats, this may be one factor to weigh alongside cost, convenience, and your dogs specific needs.
-
Review ingredient lists thoughtfully. The report notes that ingredients such as meat by-products, certain grains, seafood, and vitamin/mineral premixes may contribute to elevated contaminant levels, though it doesnt identify exact sources. That doesnt mean these ingredients are inherently harmful but it may prompt more careful label reading.
-
Talk with your vet before making changes. Switching food abruptly can upset your dogs digestive system, and not every format works for every pet. If youre considering a change, especially for puppies, seniors, or dogs with health conditions, its smart to get professional guidance.
-
Stay informed. Independent testing like this offers a snapshot in time. Monitoring updates from trusted sources can help you make decisions based on the most current information available.
At the end of the day, feeding your dog is about balancing nutrition, safety, practicality, and budget. Studies like this dont necessarily provide simple yes-or-no answers but they can give pet owners more information to work with when choosing what goes in the bowl.
Posted: 2026-02-19 18:42:22

















