What Attorneys Should Know About Pet Food Contamination Litigation: A Veterinary Microbiologist’s Perspective
- Dr. Nihan
- Feb 13
- 4 min read
Updated: Apr 4
Why Pet Food Contamination Cases Are Surging
Pet food recalls aren’t slowing down. They’re accelerating. In 2023 alone, Mid-America Pet Food issued three expanding recalls for Salmonella contamination across Victor, Wayne Feeds, Eagle Mountain, and Member’s Mark brands, eventually settling a class action for $5.5 million. A year earlier, Midwestern Pet Foods paid $6.375 million over aflatoxin and Salmonella in Sportmix and Pro Pac products. And the FDA continues to issue advisories on raw pet food brands like Darwin’s and Blue Ridge Beef almost quarterly.
What’s driving this? A few things. The U.S. pet industry hit $157 billion in 2025. More products on shelves means more manufacturing, more ingredient sourcing, more opportunities for contamination and more lawsuits when something goes wrong.
For attorneys, these cases require an expert who understands not just the microbiology of the pathogen but the manufacturing environment where the contamination occurred.
The Microbiology Behind Pet Food Contamination Cases
The most common pathogens involved in pet food recalls are Salmonella, Listeria monocytogenes, and E. coli. Each behaves differently in manufacturing environments and each requires different analytical approaches.
Salmonella is the most frequently detected pathogen in pet food litigation. It survives well in dry environments which means dry kibble, the most common pet food format, is particularly vulnerable. Unlike Listeria, which typically indicates environmental contamination in the facility (floor drains, condensation, equipment surfaces), Salmonella in finished dry product usually points to an ingredient source problem, inadequate thermal processing, or post-process recontamination.
Aflatoxin contamination is different altogether. Aflatoxin is a mycotoxin produced by Aspergillus flavus mold, typically found in corn and other grains used in pet food formulation. Aflatoxin cases often involve ingredient sourcing failures the manufacturer purchased contaminated grain and failed to test it adequately before use.
Heavy metals (lead, arsenic, cadmium) and Vitamin D toxicity represent another category. These cases often involve formulation errors or ingredient adulteration rather than microbial contamination.
Understanding which contamination type is at issue fundamentally changes the expert analysis. A Salmonella case requires examining the kill step, environmental monitoring programs, and post-process handling. An aflatoxin case requires examining ingredient supplier qualification and incoming raw material testing.
What a Manufacturing Expert Evaluates in These Cases
I’ve spent 20 years inside manufacturing operations. When I evaluate a pet food contamination case, I’m not just looking at the lab results. I’m looking at the entire system that was supposed to prevent those results.
That means examining the HACCP plan (or lack of one), the preventive controls under FSMA, the environmental monitoring program, the ingredient supplier qualification protocols, the thermal processing records, the sanitation standard operating procedures, and the finished product testing regime. Each one of these can be the point of failure and each one tells a different story about whether the manufacturer met the standard of care.
GMP compliance matters enormously in these cases. Did the facility follow its own CGMP protocols? Were deviations documented? Was the corrective action adequate? Often the answer is no, and the documentation trail (or absence of one) becomes the central evidence.
Proving Causation in Pet Food Product Liability
One of the trickiest issues in pet food contamination litigation is causation. The attorney needs to connect the contaminated product to the animal’s illness or death. This is where veterinary microbiology expertise becomes critical.
Microbiological analysis can establish whether the pathogen strain found in the product matches the strain causing illness. Epidemiological analysis can establish a temporal and exposure-based link between consumption and symptoms. And a veterinary assessment can rule out alternative causes.
In the Mid-America case, six of seven confirmed human Salmonella cases were children under one year old who had been exposed to contaminated pet food (a zoonotic transmission pathway) that requires both microbiology and veterinary expertise to explain to a jury.
The Role of the Expert Witness in Pet Food Recall Litigation
The expert witness in these cases serves multiple functions: reviewing manufacturing records and lab data, identifying the contamination source and pathway, evaluating whether the manufacturer met regulatory obligations, assessing causation between the product and the injury, and communicating complex science clearly to judges and juries.
The ideal expert combines three things that rarely overlap: deep scientific training in microbiology and pathogen behavior, hands-on experience in GMP manufacturing environments, and knowledge of the regulatory frameworks (FDA-CVM, FSMA, AAFCO) that govern these products. Without all three, critical aspects of the case may be missed.
How to Retain a Pet Food Contamination Expert Witness
If you’re an attorney with a pet food contamination case on your desk, the first step is a confidential case discussion with a qualified expert. An initial review typically takes 3–5 business days and helps determine whether the scientific issues align with the expert’s credentials and whether a supportable opinion can be formed.
Dr. Nihan Marun is a veterinary microbiologist (DVM, PhD Microbiology) with 20 years of experience in animal health product manufacturing, GMP compliance, and regulatory science. She is available for both plaintiff and defense engagements nationwide and internationally.
