Not your grandma’s milk

There are so many additives and processes involved that buying a gallon of milk or a cup of yogurt at your grocery store essentially guarantees that you'll get a mixture of substances from all over the country -- and possibly the world. But that's not where it ends; milk by-products also now appear in a wide variety of other processed foods.

Lloyd Metzger, director of the Midwest Dairy Foods Research Center and Alfred Chair of the Dairy Department at South Dakota State, outlined the process: Milk is received at the processing facilities and is tested for off-flavors and antibiotics. Several tanker trunks worth (from multiple different farms) get combined and placed in holding silos. Then the milk goes through a cream separator to create two products: cream and skim milk. At this point, various percentages of cream are added back into the skim milk in order to create whole and low fat milk. Milk is then homogenized, which is the process of passing it at high speeds through very small holes to create a uniform texture and prevent the cream from separating and rising to the top. It's then pasteurized, or heated to at least 145 degrees. In some states, non-fat milk solids are added to the milk in order to thicken it and give it a better mouth feel. Then synthetic vitamins A and D are added.

When all is said and done, the product is a far cry from the milk that actually comes out of a cow. And, depending on whom you ask, each step along the way might carry its own risks.

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