Haute Pasture recently received a lesson on rennet, and we were surprised that we, as supposed educated consumers, did not realize that all cheeses are not necessarily vegetarian. Rennet is a mix of enzymes found in a calf’s stomach that is used in nature to help the calf digest its mother’s milk, but is used in traditional cheese making to coagulate milk into cheese.
Milk-source-specific rennet can also be used; so, a lamb’s stomach could be used for rennet for sheep’s milk, and a kid’s stomach for goat’s milk. The argument against slaughtering baby animals for meat is for another post; one could make the point here that stomachs are a byproduct of veal/lamb/baby goat meat production, and it’s good that they can be used for something. This post will not dispute that, but rather discuss the alternative ways to produce cheese that do not involve the use of animal organs.
Vegetarian cheese can be made using vegetable rennet, microbial rennet, genetically-engineered rennet, or acid coagulation.
Vegetable and microbial rennets are enzymes or acids produced from plants and molds. These rennets can be difficult to obtain and may impart unwanted side-effects on the cheeses, so most cheeses in the U.S. are made using genetically engineered rennet. This rennet is produced by bacteria, fungi, or yeasts that were modified with cow genes to produce one of the enzymes in natural rennet. Vegetarian cheeses can also be made using acid coagulation, which is how cream cheese and paneer are made.
So, read the label before you purchase cheese. Whole Foods, for one, prints on cheese labels whether the cheese is vegetarian. Harris Teeter, on the other hand, lists the ingredient “enzymes” on their in-house cheese label, which could be animal-based. If in doubt, ask at the cheese counter. Or better yet, purchase your cheese from a local farmer’s market, where you can not only ask the vendor about rennet in the cheese, but also about the treatment of the livestock on the farm.