Our infant formula powders are packaged airtight and under a protective atmosphere in cans and then have a long shelf life. Once opened, oxygen and moisture enter the powder. Therefore, do not keep an open can for too long; we recommend using our powders for a maximum of 3 weeks after opening. Not that it is immediately spoiled, but after that we can no longer guarantee that it still meets our quality standards. Always store our bottle food tightly closed with the plastic lid, at a low humidity and not warmer than 20 degrees - and certainly not in the refrigerator.