Use of Rennet in Cheese May Clash with Dietary Restrictions
By Mohammad Abdullah
May/Jun 25
Cheese is a nutrient-dense dairy product that provides protein, fat, and minerals, and although it is high in saturated fat and sodium, it is rich in calcium and protein. Cheese can also be preserved for much longer than milk. Today, Americans are consuming cheese and butter at a higher rate than ever before. Recently, the United States Department of Agriculture reported that butter and cheese consumption surpassed all previous records, reaching all-time highs of 6.5 pounds of butter per person and 42.3 pounds of cheese per person per year in 2023.
“When it comes to great culinary creation, cheese has got to be at the top of the list. . . without it there would be no pizza or lasagna,” food writer DB Kelly wrote in a 2022 article for The Tasting Table.
Cheese consumption has been increasing significantly in the Middle East and other Muslim-majority regions as well. For example, in 2017, the market for certified halal mozzarella cheese from Campania, Italy had been booming with one in four mozzarella cheeses produced according to Islamic law.
In 2022, Future Market Insights noted that the demand for halal cheese is anticipated to rise at a Compound Annual Growth Rate of 4.9% from 2022 to 2032, and the global halal cheese market is expected to be worth $876.8 million by 2032. “The halal cheese market shows rapid growth which meets consumers’ increasing need for halal-certified items. The market growth is primarily driven by both the increasing Muslim population globally as well as creating awareness about Halal dietary requirements,” the report said.
While cheese is popular among Muslims, the process of making it can introduce non-halal ingredients. With cheese as with all products therefore, Muslim consumers should read food labels before buying the product. Knowing what a product is made of can help us make more informed decisions to determine if it is suitable for our diet.
Why Cheese May Not Be Halal
One ingredient often required to make cheese is a group of enzymes called rennet. The type of rennet used in cheese production is a major issue for individuals following halal, kosher, or vegetarian diets as well as other forms of dietary restriction.
Rennet is typically included in the ingredients list or listed as “enzymes” on food labels, but the source of the rennet is typically not disclosed to consumers. According to the Food and Drug Administration (FDA), “enzymes of animal, plant, or microbial origin may be declared as “enzymes” on a cheese label, with no delineation between animal forms and vegetable forms.”
According to a 2024 article on the website Love to Know, “companies often change the ingredients they use when they make a product, so a cheese made with vegetarian rennet one week may be made with animal rennet the next.” Some cheeses are even made using pork-derived rennet such as pecorino di farindola, a traditional Italian cheese using pig rennet used in the production process.
Where Does Rennet Come From?
Rennet is the general name for enzymes that act upon proteins in milk and is usually derived from the stomach linings of young animals, often calves. According to Fermentaholics.com there are four types of rennet: animal rennet typically used for traditional, pressed cheeses like cheddar, microbial rennet (made from yeast, fungi, or bacteria) often used for softer, un-ripened cheeses like mozzarella, vegetable/plant rennet used in some Irish cheeses, and Fermentation-Produced Chymosin (FPC), an artificially-produced enzyme that is used in many hard cheeses. It uses genetic engineering to produce animal enzymes in bacteria, fungi, or yeast.
According to the Genetic Literacy Project (Aug. 16, 2024), today, 90% of the cheese in the U.S. is made using Fermentation-Produced Chymosin (FPC). However, it has been banned in several countries that do not allow genetic engineering of food products. In a 2024 report, the website Food Navigator said that despite vegetarian rennet being far more prevalent than it once was, animal rennet is still present in many cheeses.
However, there are a variety of cheeses that can be made without rennet. For example, Indian Paneer is not made with rennet, and instead, cheesemakers rely on other acidic ingredients like yogurt or lemon juice to curdle the milk. Mozzarella, cottage cheese, and cream cheese also typically don’t require the use of rennet.
Scholarly Opinions Are Mixed
Islamic scholars are divided on the issue of rennet used in cheese production, particularly regarding whether rennet from an animal not slaughtered according to Islamic guidelines is permissible. Some scholars consider this form of rennet pure while others consider it impure. However, most Islamic scholars agree on the prohibition of pork-derived rennet, and the permissibility of rennet from properly slaughtered halal animals.
According to Dar Al-Ifta in Egypt, “it is permissible to eat cheese made with rennet from calves or other ruminant animals that are lawful for Muslim to eat even when these animals are not slaughtered according to Islamic precept as long as the rennet is not derived from pigs.”
And according to Yasir Qadhi, PhD, and Chairman of the Fiqh Council of North America (FCNA), “cheese, in all-of its commonly available varieties (except those that contain alcohol or pork as an added flavoring), is absolutely and totally halal.”
An article in Seekers Guidance stated, “In the Hanafi School, rennet obtained from an animal slaughtered by a non-Muslim or Muslim in accordance with the Islamic law or contrary to it, in all cases, is permissible, as-long-as the animal in question is not a pig. The fuqaha explain, however, that it is better to avoid whenever reasonably possible when its source is unknown because of the difference of opinion between the Sunni School of fiqh regarding its permissibility and the doubt therein.”
What Can Muslim Consumers Do?
According to some halal certification organizations, “while most cheeses are halal, some are doubtful or Mashbooh as many cheese brands do not explicitly state on their packaging where the enzyme used in their production comes from.”
To ensure that their cheese follows halal guidelines, consumers can call manufacturers to request to know the source of the rennet used in a given product. Manufacturers can also acquire halal certifications to appeal to customers with dietary restrictions.
This is also an opportune time for halal certification organizations to bring this issue to the FDA as the agency is currently finalizing a rule to amend regulations for certain cheeses. Consumers can also be proactive by checking the ingredients list on cheeses to ensure that the rennet used in the manufacture of the product contains a “halal” or “vegetarian” label.
Mohammad Abdullah, DVM, served 29 years with the U.S. Department of Agriculture’s Food Safety and Inspection Service, the agency that regulates the meat industry. He is also the author of A Closer Look at Halal Meat from Farm to Fork (2016).