Is cheese halal?

Cheese is milk that has been curdled and set, and the agent that does the curdling — rennet — is where the halal question lives. Milk itself is halal; the issue is whether the enzyme used to coagulate it is acceptable, and rennet comes in three broad types: microbial (grown from moulds), vegetable (from plants such as thistle), and animal (from the stomach lining of calves or other ruminants).

Microbial and vegetable rennet are not animal-derived, so cheese made with them is straightforwardly halal — and today a large share of supermarket cheese, including most cheddar and many soft cheeses, uses microbial rennet, often labelled “suitable for vegetarians”. Animal rennet is the case that needs thought: it is permissible if it comes from an animal slaughtered according to Islamic rules, but doubtful if the calf was conventionally slaughtered, which is the norm in non-halal supply chains.

Here scholars genuinely differ. One well-established position holds that rennet from the stomach of a ruminant is pure and the cheese is permissible regardless of how the animal was slaughtered — partly because rennet is a tiny processing aid and partly on transformation grounds; this is reported from within the Hanafi and some other schools. A more cautious position treats animal rennet from a non-Islamically-slaughtered animal as impermissible. Both are held by reputable scholars, which is why uncertified cheese with unspecified animal rennet is best called doubtful rather than flatly haram or halal.

Two extra things occasionally make a specific cheese haram outright: lard or other pork fat used in processing (rare, but check), and alcohol — some washed-rind and speciality cheeses are made with wine or beer. For everyday shopping, the quickest path to certainty is a “microbial/vegetarian rennet” note or a halal-certification logo. Lacking that, treat the cheese as doubtful and either choose a vegetarian-rennet alternative or follow your school's position on animal rennet.