Unrefrigerated? Sweet corn is normally packed in waxed boxes and iced soon after picking. It then goes to the produce distributor and is stored at 40-45 degrees. It can easily stay there a week or more. Then it goes to the supermarket where they keep it stored in the walk-in at 40-45. They often only get produce shipments once or twice a week, so it can be another week refrigerated. One or three days more in your fridge at home isn't going to make much difference. Either your store is putting out each days corn at room temp(likely), or they are a specialty niche place that is getting locally grown corn daily straight from the field(unlikely), in which case there is no need for refrigeration.