M.I.T. researchers who more typically work on new ways to detect chemical weapons and explosives have created an affordable hand-held sensor that can tell when fruit is ripening.
Techniques already exist to detect ethylene, a hormone that initiates ripening, in the air around fruit, but they are expensive and unwieldy. The new sensor, which need not even touch the fruit, includes tens of thousands of carbon nanotubes, with a copper compound added, and might cost as little as a dollar (including a chip that would transmit information wirelessly). Grocers wielding the device could identify which pallet of bananas or avocados to sell first; and people storing fruit could make economically sound decisions about when to subject it to expensive interventions to preserve it, including refrigeration.
Roughly 10% of produce is lost to spoilage each year, so the innovation could save millions of dollars.
The research, by Birgit Esser, Jan M. Schnorr and Timothy M. Swager — affiliated both with M.I.T.’s chemistry department and its Institute for Soldier Nanotechnologies — is described in a forthcoming article in Angewandte Chemie.