Is cheese halal? (the rennet question)

Rennet is the enzyme that curdles milk. It can be animal (from calf stomachs), microbial or vegetable. Many traditional cheeses use animal rennet.

Historically, a large body of scholars permitted cheese without investigating the rennet’s origin — the quantity used is minute and transformed. This remains the most widespread view today: cheese made with animal rennet is tolerated.

Stricter consumers prefer microbial rennet — the case for most industrial cheeses (look for “microbial coagulant” or the vegetarian label, which excludes animal rennet by definition) — or certified halal cheese. Both approaches are respectable.