It used to be that making cheese meant killing cows. Young cows, specifically—a few days old, at most. The stomach of an unweaned calf produces enzymes that turn liquid milk into good, hard, flavorful cheeses like Parmesan and Cheddar. These enzymes, called rennet, are secreted by mucous membranes that line the calf’s fourth stomach. Harvesting rennet the old fashioned way requires slicing this stomach open, which in turn requires slicing open the baby bovine itself. This, as they say, kills the cow.


For thousands of years, this was how we made cheese. Eventually, calf stomachs became a byproduct of the veal industry. But in the 1970s, America’s growing appetite for cheese collided with its mounting aversion to killing newborn cows. Anticipating a crisis of supply and demand, researchers turned to a then-unprecedented technology in food science: genetically modified organisms. The result was a genetically altered bacterium that produced cheesemaking enzymes in a beaker, instead of an animal’s stomach. This revolutionized the cheese industry. Today, the vast majority of cheese is made with enzymes produced not by baby animals, but genetically modified microbes.

By any measure, the use of GMOs in the production of cheese is among the greatest feats of modern food science. But today, that achievement is often ignored, disowned, and overlooked. At a time when “GMO” is, to many people, a four-letter word, companies like Chipotle are endeavoring to distance themselves from the technology, which they paradoxically depend on.

This is the story of how genetic engineering saved the cheese industry, and how it continues to satisfy one of our biggest culinary cravings in spite of society’s shaky relationship with GMOs.

Lastly, if you find the milk that goes into cheese is itself bothersome from an animal rights standpoint, rest assured that scientists are currently attempting to recreate the biosynthesis of cow’s milk in GM microbes. Real Vegan Cheese is a startup that aims to produce cheese exclusively with GMOs. Some vegan groups have pushed back against the vegan movement’s broad opposition to GMOs, in recognition that GMOs could make food production less dependent on animal lives. Regardless, it’ll be some time before we successfully source cow’s milk from the lab.

It’s up to you whether you consider FPC to be a GM food, vegetarian, or just a modern solution to an old problem, but it is undeniable that using genetically engineered microbes to make FPC has saved countless animal lives while keeping the cheese industry afloat. For that, we should be grateful.