How Pfizer's GMO Rennet Got Into 90% of American Cheese (And Why No One Told You)
The cheese industry has a dirty little secret: Up to 90% of American cheese is made with a genetically engineered enzyme developed by pharmaceutical giant Pfizer.
What you'll learn in this article:
✔️ How Pfizer created the world's first FDA-approved GMO food ingredient
✔️ Why up to 90% of American cheese contains GMO without labelling it
✔️ How traditional cheesemakers taste better and are more nutritious
✔️ Ways to identify and source cheese made with traditional, non-GMO methods
The Great Cheese Deception
Let's get one thing straight: The cheese your grandparents ate isn't remotely similar to what's filling refrigerators across America today. The transformation didn't happen by accident—it was engineered in pharmaceutical laboratories and rubber-stamped by federal regulators without consumers ever getting a say.
For over 7,000 years, cheesemaking relied on a simple, ancestral ingredient: rennet, an enzyme complex harvested from the stomachs of young calves. This traditional process created the cheeses that nourished civilizations and developed our collective palate.
But in 1990, Pfizer—yes, the same pharmaceutical corporation now known for other products—fundamentally altered our food supply by introducing the world's first genetically engineered food product: fermentation-produced chymosin (FPC), a laboratory-created version of rennet made by inserting cow genes into genetically modified mold.
Today, this Franken-enzyme is in approximately 80-90% of all cheese produced in the United States. Yet most Americans have no idea they're consuming it. This isn't a coincidence—it's by design.
When Wall Street Hijacked Cheesemaking
The infiltration of genetic engineering into our cheese wasn't driven by health concerns or consumer demand. It was purely about industrial efficiency and corporate profits.
By the 1960s, the cheese industry faced challenges that threatened their bottom line:
Animal rights activism was reducing veal consumption, limiting calf rennet supplies
Traditional production couldn't keep pace with industrial demand
Corporate food giants wanted cheaper, standardized production methods
Rather than adapting to these market signals by supporting more localized, traditional production, industry turned to Pfizer's laboratories for a technological quick fix.
From Pharma Labs to Your Plate
Pfizer scientists took genes from cows and inserted them into Aspergillus niger—a black mold—creating an organism that could produce chymosin in fermentation tanks. This genetic engineering experiment became the test case for our regulatory system's approach to GMO foods.
With minimal long-term safety testing and zero consumer notification requirements, the FDA approved this lab-created enzyme in 1990, establishing the precedent for genetic manipulation of our food supply. They determined that since the mold itself wasn't in the final product—just the enzyme it produced—no special labeling would be required.
Think about that: The very first GMO food product approved for human consumption was deliberately hidden from consumers through a regulatory loophole.
Pfizer later sold this business to Danish bioscience company Christian Hansen in 1996, but their scientific—and regulatory—legacy lives on in nearly every bite of commercial cheese Americans consume
The Labeling Scandal: Legal Deception
Here's where the corporate food system shows its true colors. Despite being produced through genetic engineering, cheese made with FPC requires no GMO labeling in the United States.
The regulatory distinction hinges on semantic games that would make any lawyer proud: while the microorganisms used to produce the enzyme are genetically modified, the purification process removes all microbial components. Therefore, regulators claim, the final product isn't technically a GMO—even though it could not exist without genetic engineering.
To further obscure the truth, manufacturers typically label FPC rennet as "vegetarian rennet" or "microbial rennet" on packaging—deliberately vague terms that hide its laboratory origins from consumers who have a right to know what they're eating.
Traditional Artisans vs. Big Food Science
Despite the industrial dominance of GMO rennet, a small resistance movement of artisanal cheesemakers continues to use traditional methods and materials.
At Shelburne Farms in Vermont, for example, cheesemakers exclusively use genuine calf rennet, reporting superior flavor development during aging. They note that traditional rennet contains a natural balance of enzymes that contribute distinctively to cheese flavor and texture—qualities that the single-enzyme GMO version cannot replicate.
This isn't just nostalgia—it's measurable quality. A study from the Bionutrient Food Association found that traditionally produced cheeses contain up to 28% higher mineral content and more complex flavor compounds than their industrial counterparts.
Is GMO Rennet Safe? The Questions They Don't Want Asked
The FDA and industry representatives insist GMO rennet is identical to traditional rennet and therefore just as safe. But this simplistic claim ignores several critical questions:
Why have no independent, long-term human studies been conducted on GMO rennet consumption?
How can we be certain that the purification process removes all traces of the genetically modified production organism?
Why did the approval process rely heavily on industry-funded research rather than independent verification?
If it's truly identical and equally safe, why fight transparency in labeling?
While no direct evidence links consumption of cheese made with FPC to specific health problems, the systematic avoidance of transparent labeling prevents researchers from tracking potential correlations. This creates a perfect scenario for industry: potential problems can't be proven because the exposure data doesn't exist.
Taking Back Control of Your Food
For those who believe in food transparency and traditional production methods, options do exist:
Certified Organic Cheeses : Organic standards prohibit the use of GMO-derived ingredients
European Protected Designation of Origin (PDO) Cheeses : Many traditional European cheeses still use animal rennet to maintain their protected status
Local Artisanal Cheeses : Small-scale producers often proudly use traditional ingredients—just ask them directly
Make Your Own : Traditional cheesemaking is a rewarding skill that connects you directly to ancestral food wisdom
Each cheese purchase is a vote for the kind of food system you want to support. When you buy traditional cheese from regenerative farms, you're not just getting superior nutrition—you're helping rebuild a food system based on transparency and natural processes rather than corporate manipulation.
The Bigger Battle: Food Sovereignty vs. Corporate Control
The story of Pfizer's GMO rennet represents everything wrong with our industrial food system: corporate engineering of traditional foods, regulatory capture enabling secrecy, and the systematic replacement of ancestral wisdom with laboratory science.
But this issue extends far beyond cheese. The same pattern repeats across our food supply, from lab-created meat substitutes to pesticide-saturated crops to synthetic food additives. In each case, corporations modify our food, conceal the changes through regulatory loopholes, and profit from consumer ignorance.
True food sovereignty means reclaiming your right to know exactly what you're eating and how it was produced. It means supporting producers who embrace transparency and traditional methods that have nourished humanity for generations.
The revolution won't come from corporations or regulators—it will come from informed consumers demanding better and supporting the farmers and food artisans building a more honest, regenerative food system.
Your grocery cart is a protest sign. What statement are you making with your cheese choices? Share your thoughts in the comments below!
Viva La Regenaissance!
Frequently Asked Questions
Is cheese made with GMO rennet legally allowed to be labeled as "organic"?
No. Organic certification standards explicitly prohibit the use of genetically modified ingredients, including GMO rennet. If a cheese carries the USDA Organic seal, it must use either traditional animal rennet or a non-GMO alternative like plant-based or traditional microbial rennet.
How can I tell if my cheese contains GMO rennet if it's not labeled?
Unless specifically stated otherwise, assume that most conventional cheese contains GMO rennet. Terms like "vegetarian-friendly rennet," "vegetarian enzymes," or just "enzymes" on the ingredient list typically indicate GMO rennet. Cheeses that use traditional animal rennet often proudly specify this on their packaging with terms like "traditional rennet" or "calf rennet."
Does European cheese contain GMO rennet?
Many traditional European cheeses, especially those with Protected Designation of Origin (PDO) status like Parmigiano Reggiano, Gruyère, and traditional Manchego, must use animal rennet according to their production requirements. However, many non-protected European cheeses do use GMO rennet, particularly those produced for mass markets.
Is there a nutritional difference between cheese made with GMO rennet versus traditional rennet?
The direct enzymatic function of coagulating milk is essentially the same with both types of rennet. However, traditional animal rennet contains a natural blend of enzymes (including pepsin and lipase along with chymosin) that can influence flavor development during aging in ways that single-enzyme GMO rennet cannot. Some artisanal cheesemakers report that traditionally-produced cheeses develop more complex flavors and may retain higher levels of beneficial enzymes that aid digestion.