In the house
Is rennet in cheese halal?
Updated 6 September 2026
Rennet is the question
Rennet is what sets most hard and many soft cheeses. Traditional animal rennet is an enzyme from the stomach of a suckling calf or similar animal. Microbial rennet is produced by fermentation. Vegetable rennet uses plants such as cardoon. Fermentation-produced chymosin is a named industrial version of the microbial route.
The cheese is not the issue. Milk from a permissible animal is not the issue. The enzyme is the issue.
What the label usually hides
UK and EU packs often say “rennet” or “microbial rennet”. US packs often say “enzymes”. None of those words, by themselves, tell you the animal and the slaughter. “Vegetarian” on a pack is a useful negative — it usually means no animal rennet — but it is still not a halal mark if other additives are in a processed slice.
Some cheeses also use lysozyme (E1105) as a preservative. Egg-derived lysozyme is not controversial; an unnamed enzyme still is.
What to do at the counter
If the pack names microbial, vegetarian, or vegetable rennet, the classical animal-rennet problem is not the one you have. If it names animal rennet, the same zabiha logic as gelatin applies. If it names nothing, treat it as doubtful or buy a certified block. This page will not tell you that all supermarket cheddar is forbidden. It will tell you that “cheese” is not an answer.
Quick answers
- Is vegetarian cheese automatically halal?
- Usually the rennet question is closed. Still read for flavouring and gelatin in processed slices.
- What does “enzymes” mean on a US label?
- It can be microbial, animal, or mixed. It does not name the source. That is why a mark or a named rennet helps.
- Is mozzarella in the supermarket fine?
- Only if you know the enzyme source or see a mark. The shape of the cheese is not a ruling.
General information, not a fatwa. Where scholars differ, we try to say so. For your situation, ask a scholar you trust.