Good news: month old opened almond milk is just fine!
We left for vacation near the end of July. Everything I left in the fridge was still there when we got back. Mr.BT had a freezer well stocked with tater tots and fish sticks and the pantry was not wanting for high sodium boxed cheese flavored starches. I got through the carton of almond milk that I bought when we got back, sniffed the old one, and used it pancakes yesterday and my coffee today. Happy to report that the kids and I are still alive and without any intestinal distress!