Ethylene is an odorless, colorless gas that is produced naturally by fruits and vegetables. It can increase the pace at which fresh produce ripens, shortening shelf-life. Some of the highest producers of ethylene are apples, avocados (ripe), bananas, cantaloupe, kiwi fruit, pears, and stone fruit (including apricots, nectarines, peaches, and plums). Almost all fresh produce is at least somewhat sensitive to ethylene gas. In storage, be sure to isolate the high producers from the rest of your fruits and vegetables to maximize shelf-life.