This is from the Vegetarian Resource Group Web site (http://www.vrg.org).
"Many vegetarians don't consider that some of the cheeses they are eating could actually contain unfamiliar animal ingredients. That's right cheese, a common staple in many vegetarian diets, is often made with rennet or rennin, which is used to coagulate the dairy product.
According to the McGraw-Hill Encyclopedia of Science and Technology, rennin, which is an enzyme used in coagulating cheese, is obtained from milk-fed calves. "After butchering, the fourth stomach...is removed and freed of its food content." After this the stomach goes through several steps including being dry-salted, washed, scraped to remove surface fat, stretched onto racks where moisture is removed, then finally ground and mixed with a salt solution until the rennin is extracted."
Check out this link for some cheese alternatives: http://www.vrg.org/nutshell/cheese.htm
So, even if you're a lacto-vegetarian, you must pay attention to the source of the cheese you eat.
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