A team of chemists from the Massachusetts Institute of Technology (MIT) in the USA has developed a new portable sensor based on chemically modified carbon nanotubes, which is able to detect the volatile chemical by-products of microbial meat spoilage.
The MIT researchers modified the carbon nanotubes with a metalloporphyrin containing a central cobalt atom bound to several nitrogen-containing rings. Cobalt-containing metalloporphyrins bind strongly to biogenic amines, such as putrescine and cadaverine, produced by species of bacteria that cause meat spoilage and this increases the electrical resistance of the carbon nanotubes.
The modified nanotubes were used to construct a simple and inexpensive sensor, in which an electrical potential is applied across the device and the current generated is then monitored. When amines are present the resistance increases and the current is reduced. Tests with pork, chicken, cod and salmon meat have shown promising results.
The research team says that the new sensor requires very little power and could be incorporated into smart meat packaging to provide accurate food safety and quality information. It could also be used with an existing wireless platform so that the sensor’s output could be read using a smartphone.
The sensor is described in a paper published in the journal Angewandte Chemie
and an abstract can be found here