The Pfizer Connection in Your Cheese? The Story Few Consumers Ever Heard
The untold story of fermentation-produced chymosin, hidden ingredient labels, and the growing debate over transparency in the modern food supply.
Walk into almost any supermarket in America, pick up a block of cheddar, mozzarella, Monterey Jack, Colby, or Parmesan, and chances are you’re buying a product made with a biotechnology that most consumers have never heard of.
For decades, the ingredient has quietly appeared on labels under a single, seemingly harmless word:
Enzymes.
Few shoppers realize that in approximately 90% of commercially produced cheese in the United States, and much of the industrialized world, those enzymes are not derived from the traditional animal rennet used for centuries. Instead, they are produced through a genetically engineered process known as fermentation-produced chymosin (FPC), a technology originally commercialized by Pfizer after receiving approval from the U.S. Food and Drug Administration in 1990.
The controversy surrounding FPC is not new. The technology has existed for more than thirty-five years. What is new is that millions of consumers are only now discovering its widespread use, leading to renewed debate over transparency, labeling, and informed consumer choice.
From Calves to Biotechnology
For thousands of years, cheesemakers relied upon rennet taken from the stomach lining of young calves. The key ingredient in rennet is an enzyme called chymosin, which causes milk proteins, primarily casein, to coagulate into curds.
By the late 1980s, scientists discovered they could isolate the gene responsible for producing chymosin and insert it into microorganisms such as bacteria, yeast, or fungi. Those microorganisms could then be grown inside fermentation tanks where they produced large quantities of chymosin.
After fermentation, the microorganisms themselves are removed, leaving behind purified chymosin that is chemically indistinguishable from the enzyme found naturally in calves.
The result became known as fermentation-produced chymosin, or FPC.
Pfizer’s Role
Although the concept originated with advances in biotechnology in the 1980s, Pfizer became the first company to receive FDA approval to commercially produce genetically engineered chymosin for use in food.
In 1990, after approximately twenty-eight months of review, the FDA granted FPC Generally Recognized As Safe (GRAS) status.
According to the agency’s review, fermentation-produced chymosin was considered equivalent to traditional calf-derived chymosin.
Why isn’t this bio-engineered ingredient listed on your cheeses? It’s because regulators decided that the purified enzyme itself was identical to natural chymosin; the FDA determined there was no need for special labeling identifying its genetically engineered origin.
Later, Pfizer sold its cheese-enzyme business to Denmark’s Chr. Hansen, now part of Novonesis following its merger with Novozymes. Today, Novonesis has grown into one of the largest enzyme manufacturers in the world, supplying fermentation-produced chymosin to the dairy industry while also producing enzymes used in laundry detergents, dishwashing products, textiles, biofuels, agriculture, and numerous other industrial applications (You read that correctly).
For many consumers, that realization is striking. The same corporation whose biotechnology helps coagulate the milk used to make much of the world’s cheese also develops enzymes for products found in the laundry room and under the kitchen sink.
Why Most Consumers Never Knew
This is where today’s debate begins. If FPC is used in so much cheese, why have so few people heard of it? The answer lies in food-labeling regulations.
In the United States, fermentation-produced chymosin is generally listed simply as:
Enzymes
Microbial enzymes
Non-animal rennet
Vegetable rennet
The label does not typically state that the enzyme originated through genetic engineering. Regulators classify FPC as a processing aid, not as a genetically modified ingredient remaining in the finished cheese.
The loophole is that, since the purified enzyme contains no living genetically modified microorganisms and generally no detectable recombinant DNA, current regulations do not require GMO labeling solely because FPC was produced using genetically engineered microbes.
Australia follows a similar regulatory framework through Food Standards Australia New Zealand (FSANZ), which likewise permits several genetically engineered chymosin enzymes without requiring GMO labeling when no modified DNA or protein remains in the finished product.
Is It Safe?
Regulatory agencies worldwide have consistently maintained that fermentation-produced chymosin is safe. But please remember, these are the same people who say aspartame and the COVID jab are safe.
International organizations, including the World Health Organization, the European Food Safety Authority, and numerous national food regulators, have likewise affirmed its safety when manufactured in accordance with approved standards. That should make you feel safe. The WHO is looking out for you!
What Critics Are Actually Arguing
Today, the debate extends well beyond the science itself and into the issue of disclosure. Millions of consumers have unknowingly purchased cheese made with fermentation-produced chymosin for decades because ingredient labels typically identify it only as “enzymes,” “microbial enzymes,” or “non-animal rennet.” Now that more people are learning how these enzymes are produced, many are asking a simple question: Why weren’t they told in plain language from the beginning?
Critics argue that meaningful consumer choice is impossible without meaningful labeling. Whether a person ultimately chooses to purchase these products is beside the point. They contend that shoppers should have the information necessary to make that decision for themselves, rather than discovering years later that a genetically engineered production process played a role in manufacturing one of the most common foods in their refrigerator.
For many consumers, the FDA misses the larger issue. The question is no longer whether fermentation-produced chymosin is permitted under existing regulations. The question is whether people should have been clearly informed all along that biotechnology had become the standard behind much of the cheese they buy.
What People Are Saying Online
As awareness of FPC has spread across social media, numerous additional claims have circulated regarding possible health effects.
Some individuals report digestive discomfort, bloating, constipation, or skin irritation after consuming cheeses produced with industrial enzymes. Others speculate about allergic reactions to trace fermentation residues or express concern over possible impurities produced during microbial fermentation.
Some critics also argue that insufficient long-term human studies exist regarding continuous exposure to biotechnology-derived food enzymes.
Can You Avoid It?
Consumers who prefer not to purchase cheese made with fermentation-produced chymosin still have options, although they often require more careful shopping.
Many artisan cheesemakers continue using traditional animal rennet and state so on their packaging. Certain imported European cheeses produced under traditional protected-designation rules may still rely upon animal rennet.
Some certified organic producers advertise the use of traditional or non-genetically engineered microbial enzymes, although organic certification alone does not automatically guarantee that every cheese is made with animal rennet. Consumers should verify the individual producer’s practices.
Fresh acid-coagulated cheeses, including a wide variety of ricotta, paneer, cottage cheese, cream cheese, and some fresh mozzarella, often require no rennet at all.
Reading ingredient labels carefully and contacting manufacturers directly remain the most reliable ways to determine which coagulant was used.
In Closing
Fermentation-produced chymosin is unlikely to be the last biotechnology that quietly finds its way into the food supply before the public even knows it exists. We’ve seen this pattern before. Aspartame, genetically engineered enzymes, synthetic additives, and countless processing aids have all entered the marketplace under the assurance that regulators deemed them safe, while consumers were left with little knowledge of how they were developed or why they were adopted. Whether the motivation is lower costs, higher yields, longer shelf life, or manufacturing efficiency, one principle should remain non-negotiable: people have the right to know how their food is made. Transparency should never be viewed as a threat to science or innovation. If a technology is truly worthy of public trust, it should withstand full public disclosure, not depend on ingredient labels that reveal as little as possible.