Rennet is used as a clotting agent to curdle the milk into cheese, separating the liquid parts of milk from the solids. Pfizer makes a genetically modified rennet, but because of a labeling loophole, cheese containing Pfizer’s rennet does not have to be labeled as containing a genetically modified organism.
Story at a glance:
Traditionally, cheese was made with just four ingredients: milk, salt, starter culture and animal rennet.
Rennet is used as a clotting agent to curdle the milk into cheese, separating the liquid parts of milk from the solids. It’s an essential part of the cheese-making process.
Today, there are four types of rennet used in the cheese-making industry: animal rennet, vegetable rennet, microbial rennet and a genetically modified version called FPC (fermentation-produced chymosin), made by Pfizer.
Bioengineered FPC was granted Generally Regarded as Safe (GRAS) status, which exempted Pfizer from the pre-approved requirements that apply to other new food additives. This is even though studies have detailed concerns about safety.
An estimated 90% of North American cheese is made with FPC rennet, and ingredient labels do not distinguish between bioengineered rennet and the original animal-based type so consumers have no way of knowing what they’re eating.
In this article let’s dive into why I believe you should only be eating cheese made with ANIMAL RENNET, and how over 90% of the cheese sold in the U.S. does not use this and instead uses a genetically modified organism (GMO) version made by Pfizer.
Cheese history
Who doesn’t love cheese?! And for good reason — it is not only delicious but also incredibly nutritious. And despite what the mainstream tells us, humans have been making and consuming this superfood for over 7,000 years. In fact, cheese serves an important role in human history.
Historians document that milk, dairy and fermented dairy products, like cheese, served as a nutrient-dense calorie source that was storable, allowing some of the first explorers to safely travel and expand communities, creating more demographic shifts and diverse farming communities.
“Dairy provided food security, as it is a nutrient-rich superfood.
“Consumption of milk and dairy products would have had many advantages for early farming populations. Milk, yogurt, and cheese are good sources of calories, protein, and fat. They provide a reliable food between harvests or during droughts, epidemics, or famines.
“Milk is a relatively pathogen-free source of fluids that could be critical during times of water scarcity. Cheese provides a means of storing these nutrients to be used when milk production is low, and can be easily transported.
“Furthermore, fermentation of milk into yogurt or cheese lowers lactose content and allows lactose intolerant individuals to reap the benefits, while maintain, or in some cases enhancing, other essential nutrients such as fat and calcium.”
But cheese was traditionally made with just these four ingredients:
Milk.
Salt.
Starter culture, what’s used to make the desired cheese strain (for ex. Muenster versus Swiss).
Animal rennet is used as a clotting agent to curdle the milk into cheese, separating the liquid parts of milk from the solids — a very vital part of the cheese-making process!
You add culture to milk and let it ferment. Then, you add rennet, which separates the milk into curds and whey. Then you press the curds and age them. And voila — cheese!
Rennet is a complex set of enzymes that are naturally produced in the stomachs of ruminant animals, like cows.
The main enzyme present is chymosin, which is a protease enzyme, meaning it breaks down protein. Rennet from animals also contains other enzymes like pepsin and lipase.
So these enzymes in rennet target casein, the main protein in milk. They cause the casein molecules to divide and re-coagulate into even larger clumps, forming cheese curds.
So, rennet serves as a vital part of cheesemaking since it helps curdle the milk into cheese, separating the liquid part from the solid part.
Types of rennet
There are four types of rennet used in the cheese-making industry: animal rennet, vegetable rennet, microbial rennet and FPC (a GMO version).
1. Animal rennet — Animal rennet is the most natural and oldest form of rennet, and what was traditionally used in cheese making. There are milk-clotting enzymes naturally occurring in the stomach lining of ruminant animals.
It is well known in the cheese-making industry that animal rennet produces a superior flavor, likely because this rennet is a complex set of enzymes (as nature intended), rather than a single isolated enzyme derived in a lab.
Animal rennet is usually 90% chymosin enzyme and 10% pepsin enzyme. The small amount of pepsin will break down the casein protein in milk in a slightly different way compared to just chymosin alone, producing a final product with an enhanced taste.
Cheese made using animal rennet not only tastes better, but it also produces a safer and more natural final cheese product, which will be discussed in depth below.
2. Vegetable rennet — One alternative to animal rennet is vegetable rennet, which unfortunately varies a lot depending on the source, and the term “vegetable rennet” is misused a lot.
True vegetable rennet is derived from plants that possess coagulation enzymes. These plant extracts have been used as milk coagulants since ancient times. Some examples include cardoon thistle, fig tree bark or nettles.
However, it is well known in the cheese industry that vegetable rennet can negatively impact the final texture and flavor of the cheese.“Most plant-derived [enzymes] typically exhibit low MCA/PA [milk clotting activity/proteolytic activity] ratios resulting in poor cheese yield and formation of bitter substances during cheese ripening … Therefore, most of them are not suitable for cheese production.”This is why most of the cheese with the label “vegetable rennet” isn’t real vegetable rennet. It’s either microbial rennet (made from mold) or FPC (the GMO version) since there is no regulation on the terms used for what rennet is used in cheese labeling.
3. Microbial rennet — Another alternative to animal rennet is “microbial rennet,” where the coagulating enzymes are produced by a specific type of mold, fungus or yeast organism grown and fermented in a lab setting (often fed soy). Yum. So while the microorganisms aren’t genetically modified, their food source likely is.
This is considered vegetarian-friendly as the enzyme produced by the organism is not derived from an animal. There is again a large consensus in the cheesemaking world that cheeses made with this type of microbial rennet can lead to a final cheese product with a bitter taste. This option is commonly used in “certified organic” and “certified vegetarian” cheeses.
“Microbial [enzymes] are mainly produced by fungi and bacteria in the process of growth and metabolism. Microorganisms have the advantages of a short growth cycle, easy fermentation, and are not limited by space and region of production …
“Therefore, the cost of microbial MCEs [microbial enzymes] is low … However, it is found that most MCEs have high PA and low MCA/PA ratios leading to low cheese yield and bitterness.”
4. Genetically modified FPC — To overcome some of the shortcomings of the vegetable and microbial rennets like the potential bitter cheese taste, scientists have leveraged genetic engineering technology to create new, genetically modified species that generate these milk-curdling enzymes.
Introducing the most common alternative to animal rennet in cheese making — FPC. (Chymosin refers to the enzyme that curdles milk, and is naturally present in the stomach lining of ruminant animals).
In fact, 90% of the cheese manufactured in the U.S. uses these enzymes from GMOs.
FPC was created by the one and only Pfizer (biotech company) and is made possible by using CRISPR gene editing technology where the genomes of living organisms are modified. The “safety” of FPC was evaluated by a 90-day trial in rats
How FPC is made
Here’s how it is made: The rennet-producing gene is taken out of the animal cell’s DNA string and then inserted into the bacteria, yeast or mold host cell’s DNA string in a process known as gene splicing (a type of recombinant DNA technology).
Once inserted, the newly placed gene initiates the production of the chymosin enzyme within the host. The host culture is then cultivated and fermented.
These recombinant DNA technologies are relatively new and became popular in the 1980s when the U.S. Supreme Court by a 5-4 vote ruled that new life forms can be patented.
So then in 1990, in another precedent-setting decision by a U.S. government office, the U.S. Food and Drug Administration (FDA) approved the use of FPC in food. It was the first time a bioengineered product was permitted in food in the U.S. It gets better.
This bioengineered FPC was granted GRAS status. This means that Pfizer was exempt from the pre-approval requirements that apply to other (non-GRAS) new food additives.
Since Pfizer demonstrated what is often referred to as “substantial equivalence,” the FDA concluded that bioengineered chymosin was substantially equivalent to calf rennet and needed neither special labeling nor an indication of its source or method of production.
In case you didn’t know, this “GRAS” label is a little hand-wavy and just a big loophole. In general, federal law requires the FDA to ensure that food additives are safe and mandates a rigorous pre-market safety review process. But the loophole = GRAS.
The GRAS loophole
Forty-three percent of food additives are designated “GRAS” and don’t get FDA oversight. Essentially, we must trust that food companies will conduct unbiased safety determinations before adding these new GRAS substances to our food.
“According to the FDC [Federal Food, Drug, and Cosmetic] Act, food additives that are non-GRAS need approval prior to marketing. In contrast, GRAS substances do not require approval or notification to the USFDA prior to marketing.”
Meaning the public and other regulatory agencies lack the data needed to assess the safety of some chemicals in our foods.
In 2014, former Deputy FDA Commissioner for Foods Michael Taylor commented on the FDA’s failure to regulate food chemicals, saying:
“We simply do not have the information to vouch for the safety of many of these chemicals.”
GRAS may have started with good intentions, but it has turned out to be a giant loophole for food companies to get a free pass to use chemical additives in our food with little to no oversight.
And of course, there is no other developed country in the world that has a system as archaic as GRAS for approving food additives. Okay tangent aside, back to FPC.
FPC cheese is exempt from GMO labeling
Even though the organisms that produce this FPC are genetically modified, dairy products using this technology are exempt from having to label their products as “GMO.”
In fact, FPC is just listed as “microbial rennet” or “vegetable rennet” on labels. (The source of the rennet is not required to be listed.) So it is a little deceiving.
[…]
Toxicity concerns
Toxicity means that the enzyme solution contains biotoxins from the genetically modified host (mold or fungus) that is being cultured and fermented in the lab.
The producers of these enzymes claim the final FPC enzyme solution is highly purified, but some people react as though they still contain some of the allergens from the host microorganisms themselves.
In fact, traces of the genetically engineered bacteria have been found in enzymes. A few quotes from the literature regarding these toxicity concerns. I don’t know about you, but I have no desire to consume biotoxins from genetically modified organisms!
[…]
GMO cheese may compromise your gut health
One of the biggest issues here is the potential disruption of the gut microbiome.