Pepsin — Hidden Processing Agent — Is It Vegan?

Also known as: Porcine pepsin, Stomach enzyme, Animal rennet (pepsin component)

Not Vegan

This processing agent is derived from animals or their byproducts.

Not required on labels

When used as part of the rennet in cheese production, 'animal rennet' on a label indicates the likely presence of pepsin. Plain 'rennet' is ambiguous. Most modern cheese uses microbial rennet or fermentation-produced chymosin (FPC), which is vegan.

Source

A digestive enzyme extracted from the stomach lining of pigs (porcine pepsin) or other animals. Used historically as a component of animal rennet for cheese making, and still used in some food processing applications.

Used In

Traditional cheese making (as part of animal rennet), some meat processing (tenderizing), some pharmaceutical digestive enzyme supplements, gelatine production.

How to Avoid

Look for cheeses labeled with 'microbial rennet', 'vegetarian rennet', or 'FPC (fermentation-produced chymosin)'. Most supermarket own-brand cheeses in the UK and EU now use microbial or FPC rennet. Traditional French, Italian, and Swiss PDO/AOC cheeses (Parmesan, Gruyère, Manchego) are legally required to use animal rennet.

Editorial Notes

Fermentation-produced chymosin (FPC) has largely replaced animal rennet in commercial cheese production globally — over 80% of cheese in the USA and UK is now made with FPC or microbial rennet (International Dairy Foods Association; USDA ERS). PDO-protected European cheeses are the main holdouts. This is a critical data point for vegans attempting to avoid all animal-derived processing agents.