In a startling revelation that’s raising questions about food transparency and biotech regulation, over 90% of cheese products in the United States are reportedly made using a genetically modified enzyme originally developed by Pfizer—and consumers are never told.
The enzyme, called chymosin, is a lab-engineered alternative to animal rennet, allowing cheesemakers to mass-produce cheese more efficiently. While it’s been used for decades, the public is largely unaware that it is produced using genetically modified microorganisms (GMOs)—a process that falls under a labeling exemption granted by the FDA.
Because chymosin is classified as a “processing aid”, manufacturers are not required to disclose it on packaging, despite its GMO origins. This regulatory loophole has allowed widespread use of the enzyme in everyday cheese products—from sliced singles to shredded mozzarella—without a single mention on ingredient lists.
Health advocates and consumer rights groups are calling for urgent reform. “Consumers deserve to know what’s in their food, especially when it involves genetically engineered ingredients,” said Karen Andrews, a food transparency advocate. “This isn’t just about safety—it’s about trust and informed choice.”
