I've read that the sugar count on yogurt actually reflects the lactose in the milk used in the making of the yogurt but that the culturing process changes that lactose to lactase and the actual sugar count would be less than half in the yogurt itself.

Now my question is: Are the live probiotics listed on Greek yogurt actually in the original making of the yogurt and could they be drained off when changing the regular yogurt to Greek style yogurt. I know that when I drain regular plain yogurt, the whey is very bitter. I also know that fermented foods are also very bitter. Could it be I am losing all the probiotics by draining my yogurt?