Big Pet Food’s Secret Ingredient: Why They’re Fighting to Keep GMOs Off Your Pet’s Label

Editor’s Note (Updated May 2026): When this article was originally published in 2012, California’s Proposition 37, the California Right to Know Genetically Engineered Food Act, had just been narrowly defeated — in no small part due to a well-funded industry opposition campaign. The years since have largely validated the concerns raised here.

The federal government eventually stepped in with its own GMO labeling requirement, the National Bioengineered Food Disclosure Standard, which took effect in 2022. The pet food industry got almost everything it wanted: one national standard that preempted stricter state laws, narrow disclosure requirements that exempt many highly refined GMO-derived ingredients, and the option to bury disclosure behind a QR code rather than print it on the label. The law doesn’t even use the word “GMO” — the chosen term is “bioengineered,” which consumer research consistently shows is less understood by shoppers.

The “natural” labeling problem is exactly where it was in 2012. AAFCO still has no rule barring genetically engineered ingredients from products marketed as natural. A bag of kibble loaded with GMO corn and soy can still legally carry a “natural” claim today.

The industry did shift — but only where the market forced it. Premium brands now compete on non-GMO sourcing and organic ingredients because consumers demand it. That says something about what the industry knew all along: the “natural” association with non-GMO status wasn’t a consumer misunderstanding. It was a selling point, quietly protected while mandatory disclosure was fought off at every turn.

Proposition 37, the California Right to Know Genetically Engineered Food Act 

California voters are heading to the polls tomorrow to weigh in on Proposition 37, the California Right to Know Genetically Engineered Food Act — and the pet food industry is quietly hoping they vote no.

The measure would require pet food manufacturers using genetically modified ingredients to label their products accordingly, using phrases like “Partially Produced with Genetic Engineering.” It would also strip those products of the word “natural” — a marketing staple worth its weight in gold to major pet food brands.

An Industry on the Defensive

The Pet Industry Joint Advisory Council (PIJAC) — whose board includes retail giants like Petco and PetSmart, along with Natural Balance Pet Food and several major industry trade groups — has been vocal in its opposition to the proposition. The organization argues that mandatory relabeling would drive up costs that would ultimately land on pet owners’ shoulders.

But that talking point rings hollow when you look at where the real money is going. Rather than quietly absorbing any hypothetical labeling costs, industry heavyweights have poured millions into defeating the measure outright.

Follow the Money

The opposition’s campaign war chest tells a revealing story. Nestlé USA contributed over $1.3 million. ConAgra Foods added nearly $1.2 million more. Del Monte — the company behind Milk-Bone, Pup-Peroni, and Kibbles ‘N Bits — donated $674,100. Mars Petcare, maker of Pedigree, Greenies, Cesar, and Royal Canin, chipped in $376,650. Cargill contributed $226,846, and Land O’Lakes added an undisclosed amount under $150,000.

These are not companies crying poverty. These are multibillion-dollar corporations spending heavily to ensure that a simple label never appears on your pet’s food bag.

A Simple Question

At the heart of Proposition 37 is a straightforward idea: consumers have the right to know what they’re buying. Whether you’re feeding yourself or your dog, transparency in labeling is a reasonable expectation — not a radical demand.

The industry’s aggressive and expensive campaign to block that transparency raises an obvious question: if there’s nothing to hide, why spend millions making sure no one can see?