For thousands of years, cheese production has relied on enzymes from in the lining of calf stomachs. These enzyme, known as rennet, is what coagulates and breaks down milk proteins to make firm, long-lasting cheese. Rennet can only be obtained by slicing the calf’s stomach open, and it must be harvested while the calf is still young enough to breastfeed.
Being nutritionally dense and, of course, delicious, the demand for cheese outpaced farm production in favor of factories by the 19th century. The rennet used in large-scale production was supplied as a by-product from the veal industry, and harvested calf stomachs were chopped and chemically refined to allow for consistent cheese production.
But by the 1970s, increased meat demand and criticism from the growing vegetarian community made it more profitable for many livestock farmers to let their cows reach adulthood, instead of slaughtering them early. The supply of rennet plummeted along with the demand for veal, and cheese producers turned to the newly discovered field of genetic engineering for a solution.
Scientist discovered that the enzyme chymosin was responsible for rennet’s milk-coagulating ability. In the late 80s, researchers from Pfizer successfully inserted a chymosin-synthesizing gene in Escherichia coli bacteria. Not only was this bacteria easier and more cost-effective than harvesting cow stomachs, but the final product was actually more pure than animal rennet and contained none of the bacteria used in its production. Pfizer’s product, known as Fermentation-Produced Chymosin (FPC), became the first genetically modified enzyme to be approved for human consumption by the FDA. Today 80-90 percent of cheese in the U.S. and U.K. is made with FPC.
Although cheese was one of genetic engineering’s success stories, the rise of anti-GMO sentiments are causing problems for food retailers that use cheese as an ingredient. Because none of the FPC remains in the final product, some consider cheese to be GMO-free even though it is the byproduct of genetic engineering.
Chipotle has publically stated that they will no longer use any GMO ingredients, but does that mean their burritos are no longer available with cheese? Public distrust of genetic engineering means that retailers who plan to go GMO-free will have to ask themselves some difficult questions. Is it still a GMO if genetic engineering was used in its production? And if so, where will Chipotle and other GMO-free companies get sugar for their sodas or feed or their meat?
Read a more in-depth article on genetically modified cheese, featuring Horticultural Sciences Department chair Kevin Folta, here: http://io9.com/you-can-thank-genetic-engineering-for-your-delicious-ch-1701156684