Are you sure?
We normally keep our milk for about a month (due to buying two one-gallon bottles at Costco) with no difficulty at all; in fact, the milk seems to taste better, and is more digestible when it is over a month old. I won't even open a tub of sour cream, or cottage cheese, unless it is about two months old, because of the improvement in flavor.
As for bowel irritation, etc, I found out quite by accident while I was taking Orega-Max capsules for toenail fungus, that they completely eliminated it within about five or six days.
Actually, if'n I read the article more closely, I would have seen the part about pasturization. American milk is pasturized at 72C for 15 seconds. Tests show that this will NOT kill the bacteria in question.