What are animal enzymes and rennet in cheesemaking?
In cheesemaking, enzymes are used to curdle milk, separating the solid curds from the liquid whey. The most well-known of these enzymes is rennet. Traditionally, animal rennet is an enzyme complex, primarily containing chymosin, extracted from the stomach lining of suckling calves, lambs, or kids. This method has been used for centuries and is still required for certain Protected Designation of Origin (PDO) cheeses in Europe, including some artisanal feta.
The evolution of rennet alternatives
Due to growing demand for vegetarian-friendly products and practical limitations on the supply of animal rennet, the cheesemaking industry developed alternatives. These alternatives are widely used today, and include:
- Microbial Rennet: Extracted from fungi, like Rhizomucor miehei, and purified to avoid any unpleasant byproducts. Modern microbial rennets have improved significantly over time and no longer have the reputation for causing bitterness in aged cheeses that earlier versions had. They are a very common and reliable alternative.
- Fermentation-Produced Chymosin (FPC): Created by inserting the animal rennet gene into microorganisms like bacteria or yeast. These genetically engineered microorganisms then produce the chymosin enzyme during fermentation. FPC is often purified to be chemically identical to animal chymosin and is widely used in industrial cheese production.
- Vegetable Rennet: Sourced from plants that contain coagulating properties. Examples include the thistle (Cynara cardunculus) and fig sap, which have been used for centuries. This type is less common in commercial production but still used for some specialty and artisan cheeses.
How to tell if your feta cheese is vegetarian-friendly
Since traditional feta uses animal rennet and modern versions often use vegetarian options, determining the type of coagulant is crucial for those with dietary restrictions. Unfortunately, labeling in many countries does not mandate specifying the source of the enzymes, though many conscientious brands will.
Here's what to look for on product labels:
- Clear indication of 'vegetarian': Many brands that use non-animal rennet will explicitly state 'suitable for vegetarians' on the packaging.
- Specific rennet types: Look for terms like 'microbial enzymes,' 'vegetarian rennet,' or 'vegetable rennet' in the ingredients list.
- Generic 'enzymes': If the label only lists 'enzymes' without further clarification, the feta likely contains animal rennet, though this is not a guarantee. Your best bet is to avoid it if you're concerned.
- Origin information: For products with PDO certification, the regulations may specify the use of animal rennet, though this is more of a concern for aged hard cheeses like Parmigiano-Reggiano. European Feta PDO regulations dictate it be made from sheep or a mix of sheep and goat's milk, but modern producers often use vegetarian-suitable rennets.
Navigating labels for specific dietary needs
Feta and the Vegetarian Diet
For vegetarians, the primary concern is the presence of animal rennet. Because so many modern, mass-produced cheeses, including feta, use microbial or plant-based rennets, finding a vegetarian-friendly option is often straightforward by checking the label.
Feta and Religious Diets (Halal/Kosher)
The source of rennet is also a key factor for those adhering to halal or kosher dietary laws. Cheeses using microbial or fermentation-produced chymosin (FPC) rennets can be certified halal or kosher, as long as all other ingredients meet the requirements. Products certified as such will typically carry a corresponding symbol on the packaging.
The nutritional profile of feta cheese
Regardless of the enzyme source, feta cheese offers a nutrient-dense addition to a balanced diet. It is a notable source of protein and calcium, especially when made from sheep or goat's milk. However, it is also known for being quite high in sodium due to the brine used during its ripening. Moderation is key, especially for those watching their sodium intake.
Nutrient Comparison: Feta vs. Other Cheeses
| Feature | Feta (Traditional) | Mozzarella (Traditional) | Cheddar (Aged) |
|---|---|---|---|
| Milk Source | Sheep and/or Goat's Milk | Cow's Milk | Cow's Milk |
| Typical Rennet | Historically animal, now often microbial | Historically animal, now often microbial/FPC | Often animal, but vegetarian options available |
| Texture | Crumbly and soft | Soft and elastic | Hard and dense |
| Flavor | Tangy and salty | Mild and milky | Sharp and nutty |
| Production Method | Cured in brine | Stretching of curd (pasta filata) | Matured for months or years |
| Sodium Content | Relatively high due to brine | Lower than feta | Varies, but often moderate |
Conclusion
While traditional feta cheese historically contained animal enzymes derived from rennet, the landscape of cheesemaking has changed significantly. Today, a vast majority of feta produced for the mass market uses vegetarian-friendly microbial or fermentation-produced rennet alternatives. Consumers can easily find suitable options by carefully checking product labels for specific terms like 'microbial enzymes' or 'vegetarian rennet.' By being mindful of ingredient sourcing, you can continue to enjoy delicious and nutritious feta cheese in a way that aligns with your dietary and ethical preferences. This transparency allows for an informed decision, ensuring your nutrition plan meets all your personal criteria. Secret Lands Farm is a resource that explores rennet and cheese-making history further, emphasizing traditional practices versus modern alternatives, which may be helpful for those interested in the full artisan process.
