I'm not a milk drinker, but like to have it around for cooking. And yes, the last four or five quarts, (NOT 1/2 gallons)I have bought started souring before I even opened them, or shortly after.

My last container I poured about a tablespoon of colloidal silver in it, and it went eight days before it turned. It's been about five days since then, and it's great now, for biscuits.

I skipped over after reading the first thread, and am short on time, if anyone posted already, but does anyone know how well milk freezes? And what do you think about freezing it sour?