Food Waste Sensor

Food waste is an issue for individuals, producers, and transporters. While there are multiple contributors to food waste globally, one source that is difficult to detect and control is food waste as a result of rot during transport. Four chemists from the Massachusetts Institute of Technology published a paper in March of 2020 about a new sensor they had created that can pick up minute traces of ethylene gas, as low as 15 parts per billion. They see their sensor as the first commercially feasible candidate for ethylene detection amongst produce and flowers, which start producing ethylene as they start to bloom, reach peak ripeness, or start experiencing environmental stress (for example, from being exposed to too much heat). The “sensor” is actually a dense cluster of carbon nanotubes within a glass slide. The carbon nanotubes contain a metal catalyst called palladium that adds oxygen to ethylene. It is a complex process, but essentially the palladium gains electrons, and the electrons cause the electrical current in the carbon nanotubes to shift, a shift that can be monitored to indicate ethylene is being released by the fruits or flowers. While the authors of the paper see their invention as a strong commercial candidate, the design still has to be refined for that to become a reality. There might also be an issue of waste; the authors state that the sensor is usable for five days, implying that the efficacy of the sensor is short-lived. Can parts be recycled or refurbished in some way so that new sensors don’t have to be continually purchased and there is less waste? Questions of commercial viability and waste linger, but seeing as this is a relatively new technology, it is likely that they will be addressed as time goes on.

Fong, Darryl, Shao-Xiong Luo, Rafaela S. Andre, and Timothy M. Swager. “Trace Ethylene Sensing via Wacker Oxidation.” ACS Central Science 6, no. 4 (2020): 507-512.


Monitoring, Pollution, Regulation