To store your pumpkin cake bars and maintain their freshness, use an airtight container or wrap them individually with plastic wrap to prevent drying out or absorbing odors from the fridge. Both methods will keep them fresh for up to 5 days in the fridge. For longer storage, freeze leftover bars by wrapping each individually, placing them in an airtight container or freezer bag labeled with the contents and date. Frozen bars can be kept for up to 3 months and should be thawed in the refrigerator before enjoying. While cream cheese frosting doesn't freeze well, you can add it after thawing for the best results.