Bellucci rennet powder is available in a variety of compositions, for the production of fresh (low concentration rennet) and mature cheese (higher concentration), or even for organic productions. Paste rennet from suckling goats or lambs is the oldest known form of animal rennet. It is not extracted by maceration. The fourth stomach (abomasum) of young suckling animals is rested with dry salt, alternating layers of animal tissues with layers of salt. At the end of this phase, the semi-dry stomachs are finely ground and stored in barrels with the addition of NaCl. It is ideal for producing tangy and very strong cheeses. Liquid rennet is obtained by grinding deep-frozen stomachs that are milled and put into an enzyme extracting solution with the addition of acid brine. The rennet extract then goes through a purification and/or filtering process. Coagulation is controlled by adding salt solution, or other products, or by means of ultrafiltration. In view of the high salt content (from 17 to 19%), sodium benzoate is added to liquid rennet in levels down to less than 0.5% as preservative in order to ensure that it remains microbiologically stable for a long time. The different types of liquid rennet are then mixed to produce cheeses with a short, longer and long maturation cycle.