To maximize the freshness and shelf life of Italian fennel, here are some storage tips: Store the fennel bulb in the refrigerator, either in a perforated plastic bag or wrapped in a damp towel. This will help to keep the bulb moist and prevent it from drying out. Avoid storing the fennel bulb near produce that produces ethylene gas, such as apples, pears, and bananas. Ethylene gas can cause the fennel to spoil more quickly. Use it within 3-5 days of purchase for best quality and flavor.