why isnt yogort pasturized?

Question

Why isnt yogort pasturized when buttermilk and sour cream are?

And by that I mean buttermilk and sour cream both use bacterial cultures to sour them, but are pasturized before going to the store. Yet yogort still has live bacterial cultures in it. (All three are pasturized as milk before being proccessed of course though)

Why is it nececary for yogort bacteria to remain alive while buttermilk and sourcream can be killed?

I'm asking this because I only had a little bit of buttermilk left, so I mixed in regular milk and left it on the counter overnight, yet the next day it was still just regualr milk. I inspected the package to discover that it was pasturized.

And sour cream, I think most commercially avalible sour creams are artificially soured, but my question is really more about buttermilk vs yogort. Why one has live bcteria but the other does not.

Answer 1

Because the active cultures in yogurt are good for your digestive system. They are "cultured" under controlled circumstances; the bacteria that grow in soured milk/buttermilk/cream are not and are usually harmful.

To meet the National Yogurt Association’s definition of yogurt, the probiotics or live cultures added to yogurt must include Lactobacillus bulgaricus and Streptococcus thermophilus. Probiotics—also known as beneficial bacteria—occur naturally in our digestive tract, but they need regular replenishing. Studies show they improve intestinal function, promote good digestive health, and enhance our body’s defenses against a number of ailments.

Answer 2

Actually, yogurt is derived from pasteurized milk. Here is an interesting article:

http://www.aboutyogurt.com/lacYogurt/

Answer 3

because there's not enough pastors to bless the yogurt!