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Fact vs. Fear: Are GM Enzymes in Cheese Safe?

June 11, 2014
On June 6, 2014, Scientific American released an entertaining blog entitled “Genetically Modified Cheese… is Nothing Safe? At the Boundaries of GMO Controversy” written by Kevin Bronham, Curriculum Fellow in the Microbiology and Immunobiology department at Harvard Medical School.

Bronham’s article provides a common example of the use in biotechnology in food production to show how opposition to GMOs isn't based in science.

In cheese-making, it's necessary to use "rennet,” which causes the milk to coagulate, allowing you to separate the curd. The part of rennet that’s most important for this process is called “chymosin,” which is an enzyme. A common source for rennet is usual source of rennet is the lining of calf stomachs.

With biotechnology, it’s easy to make a bacterium or yeast cell that makes of chymosin – the exact same protein that’s found in the stomachs of calves – without all of the fuss and bother attendant with raising and killing cows. This process is also much more controllable and returns a more consistent product than processing from an animal source, meaning that cheese-makers can expect very little variation in their process.

Recombination is a technical process that brings together two different sources of genetic material to create sequences that would not otherwise be found in biological organisms. Creating recombinant DNA is possible because DNA molecules from all organisms share the same chemical structure. By combining two or more strands together, one can create genetically superior organisms that have wide ranging benefits.

Having explained this, Bonham raises the question: “Would opponents of GMO technology object to eating cheese made in this way? Avoiding it might be hard – between 80-90 percent of hard cheese produced in the United States is made with recombinant chymosin. And what about companies like Whole Foods that are moving to label all of their products that contain GMOs, or states that are passing laws to do the same?

Even with these reassured facts, anti-GMO activists still objectify the use of chymosin (and even citric acid, which is just a chemical compound) because it poses a “GMO-risk,” an expression that is technically meaningless.

In conclusion, Bronham understands that anti-GMO activists are concerned about GMO foods and crops; but most of their fears are rebutted in facts. The fact is that this process of producing chymosin has been FDA approved since 1991.

“…But the objection to using purified proteins, or even chemical compounds, that are 100 percent identical to that from other sources, just because it’s being made in a lab demonstrates the rank ignorance that characterizes the professional anti-GMO movement.”