The coagulation of milk is the main step for producing cheese,
and coagulating enzymes have been utilized for centuries in cheese
manufacturing. Rennet from the fourth stomach of the unweaned
calf is believed to be an ideal and most widely used coagulating
agent in cheese making. However, limited supply and high price
of rennet, religious factors (e.g., Islam and Judaism), diet (vegetarianism)
or ban on recombinant calf rennet (in France, Germany and
The Netherlands) have prompted searches for alternative milk clotting
sources