01/10/2026
🚨 A recent article from the Daily Mail has reignited debate about a practice that's been standard in the dairy industry for over three decades: the use of fermentation-produced chymosin (FPC), a genetically engineered enzyme originally developed by Pfizer, in roughly 90% of cheese produced in North America.
Traditional rennet, sourced from the stomachs of young calves, has long been the classic coagulant in cheesemaking.
But with cheese consumption in the U.S. now surpassing 40 pounds per person annually, an alternative became essential for scalability, consistency, and cost.
In 1990, Pfizer scientists isolated the gene for chymosin (the key enzyme in rennet) and inserted it into microorganisms like bacteria, yeast, or mold.
These microbes are fermented in industrial tanks to produce chymosin that's chemically identical to the natural form, often yielding up to 1% more cheese from the same milk volume, without animal sourcing.
Pfizer later sold this technology to Chr. Hansen in 1996, and the company remains a primary supplier today.
This enzyme enables many commercial cheeses like cheddar, mozzarella, and processed varieties, to qualify as vegetarian, kosher, or halal when no other animal ingredients are involved.
The FDA granted FPC Generally Recognized as Safe (GRAS) status, a designation that has drawn sharp criticism as a regulatory loophole.
Under the current system, companies can self-determine that a substance is GRAS based on their own safety evaluations, often without mandatory FDA notification or full pre-market review, unlike other food additives.
For FPC, approval rested partly on a 90-day rat feeding study, with no requirement for longer-term human studies due to its claimed equivalence to traditional rennet.
Critics, including former FDA officials, have long argued this self-regulatory approach lacks sufficient oversight; one former Deputy Commissioner for Foods stated, "We simply do not have the information to vouch for the safety of many of these chemicals."
Read more at https://www.dailymail.co.uk/sciencetech/article-15439443/cheese-Pfizers-ingredient-dairy-products.html
