A baby food pouch that contains ice cream, frozen fruit pulp, or other items that require low storage temperatures are best stored in freezers. They may or may not spoil in the heat of a room, but they can become un-consumable. Very few people will like to eat melted ice cream, or chocolate that has turned into a cocoa paste (although it might still be fit for consumption). So even though most stand up bags are able to withstand room temperature without any damage to their structure, this may not be the case with the food they are carrying.
A class of stand up pouch bags used to store baby food is designed to bear temperatures of close to 100 degree Celsius. This is much more heat than possible under natural circumstances, even in the Sahara. Other stand up pouches for food packaging may not be so well designed.