Fresh produce left on the counter ripens so quickly because of a natural ripening agent called ethylene gas. If you have produce that can't be refrigerated, like onions, tomatoes, bananas, avocados and other fruits and vegetables, do one thing to help extend their freshness: Wrap them in small sheets of newspaper. Newspaper is designed to absorb ink, which makes it great at absorbing other things, including excess ethylene gas. And the newspaper also cushions produce, preventing bruising that can accelerate ripening, too.
ANDREWS MCMEEL SYNDICATION