Schmid documents eight enzymes in raw milk, their function, and how they respond to pasteurization.
Lactase – Lactase is a sugar found only in milk and "splits lactose into simple sugars galactose and glucose." Pasteurization inactivates lactase and requires the human digestive system to break down lactose, something many people are unable to do, and are called "lactose intolerant." Schmid writes that many people diagnosed as lactose intolerant can drink raw milk without ill effect because lactase helps them digest the lactose.
Galactase – This is the enzyme that "plays a vital role in the devopment of the nervous system." It too, is inactivated by pasteurization.
Lactoperoxidase – This enzyme is known to "seek out and destroy bad bacteria in milk."
Lactoferrin – This enzyme helps destroy pathogens in milk including tuberculosis and Candida albicans. It also assists in the absorption of iron. It also "strengthens the immune system and supports growth in children." It is "greatly reduced by pasteurization and destroyed by UHT [ultra] pasteurization."
Catalase – This enzyme helps protects cells and is inactivated by pasteurization.
Amylase – This enzyme helps digest starches, but is again, inactivated by pasteurization.
Lipase – This enzyme assists in the digestion of fat—particularly important in children. Pasteurization inactivates it.
Phosphatase – This enzymes role is unclear, but its presence is used as the test of the success or failure of pasteurization.
Raw milk itself, is a wonderfully healthy food, but fermentation seems to enhance the nutritional qualities of milk. Some studies have "described reports indicating that infants fed kefir, a fermented milk beverage from the Caucasus region, retained more calcium, nitrogen, phosphorus, iron and fat than infants fed regular milk. Yet another article showed why this is true: the fermentation process renders calcium and phosphorus (and perhaps other nutrients) more available for absorption." (Schmid, p. 348) In addition, "Fermented milk products also have powerful bactericidal properties." This means that bacterial pathogens are destroyed by fermented products such as yogurt.
Raw milk provides great nutritional benefits in both its natural and fermented states. But, pasteurization was introduced for valid reasons, which we'll discuss next.