THE RIPE STUFF

No more sour grapes? M.I.T. researchers have created an affordable hand-held sensor that can tell when fruit is ripening. Techniques already exist to detect ethylene, a compound involved in ripening, in the air around fruit, but they're expensive and unwieldy. The new sensor, which also measures ethylene molecules, includes tens of thousands of carbon nanotubes, with a copper compound added, and might cost as little as $1 (including a chip that would transmit information wirelessly). Grocers wielding the device could identify which pallet of bananas or avocados to sell first. Roughly 10% of produce is lost to spoilage each year, so the innovation could save significant money.