If you’ve ever wondered why those little juice boxes don't need to be refrigerated when other juice does, look no further than the box itself. Paperboard juice boxes are aseptic containers, which means they remain sterile without refrigeration.

The juice box’s aseptic packaging process involves several layers of raw materials, including a consumer plastic called polyethylene, which prevents liquid from getting in or out. Paperboard juice boxes also use aluminum foil, which protects against light and oxygen exposure.

Unopened, properly stored juice boxes can sit comfortably in your pantry or refrigerator for up to three months, but even a small puncture can allow mold or germs into the drink. Estimates on how long an opened juice box can last in the fridge vary, from three days to one week.