Immediately place them in a bag and store them in your refrigerator. Avoid exposure to sunlight or air, which can cause carrots to worsen in quality. To store carrots in the refrigerator for a long period of time (say, more than three days), try to keeping them in an airtight and zip-top or vacuum-sealed bag is the most efficient. The bag’s seal helps control the humidity (refrigerators tend to create dry conditions, which causes food to dehydrate).