It is estimated that ninety to ninety-five percent of U.S. cheeses use fermentation produced chymosin (FPC), a genetically modified enzyme used to coagulate milk in the cheese making process. FPC, a synthetic substance, was developed by Pfizer in the late 1980’s and approved by the FDA in 1990. Labeling regulations do not require specifying the source which can be misleading to consumers.

Prior to using a synthetic genetically modified enzyme, milk cheese was made with animal rennet for thousands of years by our ancestors. Animal rennet is an enzyme that naturally occurs inside the stomach chamber of ruminant animals. The use of microbial and vegetable enzymes has also been used in the cheese making process but they experienced a surge in the 1960’s due to a shortage of animal rennet. Vegetable enzymes typically come from plants like thistle, nettles or a fig bark which contain enzymes capable of coagulating milk.

The key to knowing if rennet or an enzyme is used is to read labels. A label listing animal rennet clarifies what is used. If the label specifies ‘vegetable enzyme,’ it strongly suggests the coagulant is plant-derived rather than FPC. However, labeling regulations can be vague, and some manufacturers might not clearly distinguish between plant-based enzymes and FPC on labels. If the label reads ‘enzyme’ it is highly likely that FPC is used as a coagulant.

Cheese made with animal rennet is more digestible than the cheese made with synthetic enzymes. Health problems associated with synthetic enzymes are allergies to cheese, digestive issues, disruptive gut health, and difficulty for the kidneys filtering out the FPC.

A key factor is to choose USDA organic cheeses because they will ensure that either animal rennet or a plant-based rennet was used in the cheese making process. It is safe to assume that all commercial cheeses are made with FPC since we know ninety to ninety-five percent of cheeses use FPC as a coagulant.

For cheeses containing no FPC synthetic enzymes, select Rumiano, Organic Valley or Cadia brands of cheeses located in our dairy cooler. Please contact me at rick@georgetownmarket.com with any questions.

(DISCLAIMER: The information provided has not been evaluated by the FDA and is not intended to treat, diagnose, cure, or prevent any disease. It is not a substitute for the advice of a qualified healthcare practitioner.)