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When most of us buy a type of cheese, we select it because we want to bite into that particular delectable taste and chewy texture. Many of my readers also prefer cheese that is organic and even raw when possible. But do you know what type of rennet or coagulator was used to turn that milk into cheese – and why you might want to be even more choosey about your cheese?
On my Eat, Pray, BUGS tour, we have been meeting artisan cheese-makers in small European towns that have inspired me to learn more about the different types of rennet and coagulators that help transform milk into different kinds of cheese.
In America and the UK, most of our cheeses are made with a variety of coagulator alternatives – the most common of which is bio-engineered. Since the FDA does not require labels to indicate what kind of rennet is being used, I’d like to share some really cool tips to help you navigate your coagulator of choice.
The History of Rennet and Cheese-Making
Most sources place the origins of cheese-making to 5500 to 6000 BC or earlier. (1,2) Interestingly, researchers recently found milk-fat residues in pottery dating back about 7,200 years along the Vistula River in Poland. (3) While most agree that the origins of cheese were a result of spontaneous fermentation of milk, the cheese industry probably would not exist today if it had not been for the discovery of rennet.
Rennet is a digestive enzyme mixture found in the stomachs of ruminant animals that happens to possess the property of curdling milk. (“Ruminant” refers to any mammal that is able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion.) Rennet consists of digestive enzymes such as lipase for digesting fats, protease and pepsin for digesting the proteins, but primarily it is its content of an enzyme called chymosin, or rennin, which separates the curds and whey necessary in the initial stages of the cheese-making process.
The use of rennet as a coagulator of milk is thought to have been discovered during attempts to transport milk in containers made from the stomachs of cows or other ruminant animals. Most believe that it was the residual amount of rennet made in their stomachs that mixed with the milk during transportation that initiated curdling, thus preserving the milk.
Rennet is Not Vegetarian
While rennet is found in the stomachs of most ruminants, the best quality rennet for making cow’s milk cheese is, sadly, extracted from the stomachs of calves as a by-product of the veal industry. In the same way, lamb and young goat rennet is used for making sheep and goat cheeses.
This makes rennet-based animal cheeses extremely controversial, especially for vegetarians.
This Common Rennet Alternative is Vegetarian… and Bio-Engineered
Fortunately, due to the worldwide growth of the cheese industry, a weakening veal industry, and a global outcry against killing ruminant animals, rennet is rarely used in the US. Even in Europe, fermentation-produced chymosin (FPC), which is a genetically modified organism, has become the preferred coagulant. Unfortunately, labeling of such is not required.
FPC, as a bio-engineered rennet alternative, was introduced in 1990 and quickly became the preferred coagulant because it was inexpensive and produced a more consistent and reliable cheese than the other alternatives that existed at the time. By 2008, up to 90% of the major cheese manufacturers in the US and UK were using FPC.
FPC is made by inserting genes from rennet-producing stomach cells into bacteria, yeasts or fungi, which then begin to produce chymosin during a fermentation process. Manufacturers are quick to point out that while the bacteria, fungi or yeast that make the chymosin are genetically modified organisms (GMO), the chymosin — which is identical to animal rennet — is not GMO, but is officially labelled a bio-engineered product.
Many Bio-Engineered Foods are Considered ‘Natural’
While bio-engineered foods (not GMO) are generally considered safe, they are still controversial, and I believe consuming them should be a personal choice. To do so, we need to be armed with the right information regarding what they are. For example, citric acid, xanthan gum and carrageenan are some of the common bio-engineered food additives (made by genetically modified microbes) found in many natural food products. To see the FDA’s list of bio-engineered food additives, please see this link. (5)
The Labels to Look For
Fortunately, both GMO and bio-engineered products like FPC exist outside the standards for the USDA “Certified Organic” label, (4) so to avoid bio-engineered rennet, buy organic.
Organic cheeses, however, can be made of animal rennet. To be sure you are not getting animal rennet, look for two labels occurring on the same product: “USDA Organic” and a Kosher label. Kosher foods are not allowed to mix meat and milk together, thus a dairy product containing animal rennet cannot be classified as kosher.
Reading the Kosher Certification
There are different kosher certification organizations, each using its own symbol to designate its products as such. While many of them contain a “K” for “kosher,” some of them are more obscure and need a bit of decoding to the untrained eye. A quick internet search can speedily educate you on the gamut of symbols used to signify a kosher rating on a packaged food.
In addition, a certified kosher cheese will also likely have a “D” printed next to its certification symbol – indicating that it is a kosher dairy product.
Buying kosher ensures you are not getting animal rennet, and organic means — among other things — that you are not eating a bio-engineered product made by genetically modified organisms.
While FPC-coagulated cheeses are approved by the World Health Organization (WHO), and of course, the FDA, and can also be certified kosher and halal for vegetarians – they cannot be labeled organic.
A Cheese Touting Microbial Rennet May Actually be Bio-Engineered FPC
The microbial-rennet-making process uses molds like Rhizomucor miehei that naturally make enzymes (not bio-engineered) similar to chymosin. While it is considered a vegetarian process, it is not known for producing reliably great-tasting cheese. Before 1990, when FPC was introduced, most of the US cheeses used this type of coagulant. While still used in the US, today the preferred non-animal rennet is the FPC. Again, because there are no labeling requirements in the US for the type of rennet used, cheeses often labelled microbial rennet are actually FPC.
Vegetable Rennet and Coagulants
There are many plants that produce enzymes similar to those in rennet that can be used to make cheese. Some of the vegetarian plant-based coagulants that have been used around the world to make cheese are:
- Caper leaves
- Thistles – the extract is called cynara
- The Mallow plant family
- Ground Ivy
- Phytic acid from soy beans
In Part 1 of this series on Euro-Vedic Cheese-Making, I discuss many of the most typical vegetable-based acid coagulants still used to make the simplest cheeses around the world today, such as paneer, cream, cottage and ricotta cheeses.
Rennet-Less Vegetarian Cheeses
Cheeses made without rennet are typically soft and surrounded by some liquid in the packaging. These cheeses are great for lacto-vegetarians as they are still commonly made without the use of rennet:
- Cottage cheese
- Cream cheese
- Some types of goat cheese
- Some types of mozzarella
- Ice cream, sour cream and yogurt are also made without the use of rennet.
Trader Joe’s is one supplier that has gone through the trouble of creating a pamphlet they call a “Rennet List,” which lists all of the cheeses they carry and the exact source of rennet used in the production of that cheese. [update: this is no longer available on Trader Joe’s site](6)
Appreciating Rennet-Free Ayurveda
While Northern Europeans may not have survived some long winters without cows and cheese, it is clear that the microbiological health benefits delivered from regularly eating cheese were not dependent on pasteurization or rennet.
Perhaps a thousand years before the discovery of rennet, farmers were making cheese with raw milk using spontaneous fermentation. When milk is warmed and left to sit at room temperature, it naturally coagulates. The lactic acid bacteria in the milk starts eating the milk sugar (lactose) and produces more lactic acid. When more lactic acid is produced, the increased acid (lower pH) starts breaking down the hard-to-digest casein, rendering the cheese lactose- and casein-free, which most folks can digest without problems. This spontaneous process is hypothesized to be the origin of cheese around the world – and a great effortless way to preserve milk! (7)
In India there is a famous cheese called paneer, which to this day continues to be touted for its health benefits. Paneer is simply the curds of whole milk that have been brought to an almost-boil with lemon juice added as a coagulant to separate the curds from the whey. We frequently make paneer at home, which is a delicious source of vegetarian protein and surprisingly easy to make – and even easier to eat! >>> My wife’s recipe for making homemade paneer.
Paneer and other simple cheeses from around the world have provided traditional people a natural source of healthy microbes that boost immunity, as well as support innumerable health and psychological benefits that we are only just now beginning to understand.
At the end of the day, when sourcing cheeses, here are some of my takeaway tips:
- Dairy and cheese products are not a requirement for optimal health.
- When eaten in small amounts and in the right season, dairy and cheese products can be a source of good probiotic bacteria. As all fermented foods, including cheese and yogurt, are acidic and heating to the body, take the season and your body type into consideration. Consume more in the winter (vata), less in the summer (pitta) and even less in the spring (kapha).
- Eat simple, organic, rennet-less cheeses, like the ones mentioned above.
- Organic yogurt is a great source of probiotics, and doesn’t contain rennet.
- Most importantly, if you want to eat hard cheeses, look for the “USDA Organic and Kosher” labels. Since you can’t be sure what type of rennet or coagulant has been used, know that “USDA Organic” eliminates bio-engineered FPC rennets, and “Kosher” eliminates all animal-derived coagulants like lipases and rennet. Since cheese labeling isn’t specific, you can deduce that if the cheese is labeled “USDA Organic and Kosher” it was made using one of the following non-animal and non-bio-engineered coagulants that I have described in more detail above:
- Microbial enzyme coagulant: natural coagulating enzymes from mold
- Vegetable rennets
- Rennet-free cheeses
With these tips in mind, and an eye on balance, enjoy delicious, health-supportive, microbiome-nourishing cheeses as part of la dolce vita.