Generally, the Halalness of a food product is determined by its ingredients (internal factor) and the process at which it is prepared, manufactured, stored and distributed (external factors). In order for a product to be truly Halal, it must be free from any non-Halal ingredients. The food product should not, by any chance, come into contact (cross contamination) with any non-Halal items during the preparation, production, storage and distribution stages. This is the same for rennet that is commonly used in the making of cheeses. Cheeses made with rennet enzyme is Halal if the calf is slaughtered according to Islamic rites. Likewise, it is deemed as non-halal if it is made with rennet enzyme that comes from a non-halal source.