No one likes spoiled fruit, especially the stores that have to eat the cost of the wasted food. Catching when fruit is about to go bad and selling it before it turns would be ideal, and a new sensor from MIT will help shopkeepers do just that and save the roughly 10% of fruits and veggies that go bad on store shelves every year. Best of all, it could potentially be done with cheap electronics and almost no energy use.
According to MIT News, the sensors could "detect tiny amounts of ethylene, a gas that promotes ripening in plants. [MIT chemistry professor Timothy] Swager envisions the inexpensive sensors attached to cardboard boxes of produce and scanned with a handheld device that would reveal the contents’ ripeness. That way, grocers would know when to put certain items on sale to move them before they get too ripe."
Right now, equipment used in warehouses to detect amounts of ethylene are very expensive, but Swager says that the MIT research team built a small sensor using carbon nanotubes, copper and polystyrene, which can detect levels of ethylene as low as 0.5 parts per million. While the ingredients for the sensors are not exactly earth-friendly, if they last awhile and can spare food from being wasted, they just might be worth it. A lifecycle analysis of what it takes to build (and recycle?) the sensors compared to the resources they are able to save would be very interesting. Also, they'd be affordable -- a sensor for a box of produce could be as cheap as $0.25, and an RFID chip that could communicated with a handheld device to display ethylene levels would add just $0.75 more.