People perceive food differently, for someone who, as they say, has a tinned stomach, nothing will come from stale food, and someone has diarrhea. Analyze yourself as an organism, remember similar situations and, if you have not previously suffered from stale, eat. No - no
Better not. There was a case when they were poisoned with a shorter shelf life without a refrigerator. You can hike so that the geyser will open for a long time and with temperature. If you have nothing else, you can boil well and eat right away.