Move over MIT chemists, Japanese scientists have developed a transparent film to detect when fish or meat is spoilt. When placed on food, the 1 cm long plastic film reacts to food products, and detects food spoilage.
Lead author Shizuo Tokito from the Yamagata University in Japan who led the team said the sensor works by detecting histamine, which accumulates when bacteria begins to decompose amino acids and even small amounts of which can cause symptoms of food poisoning.
The sensor comes integrated with an electrically conductive material on a plastic film and is expected to be improvised using wireless circuitry into the sensor film so that food freshness can be monitored by smartphones.
Compared to other sensors in the market, Japanese have developed sleeker and smaller versions. It may take three years to develop a commercially viable prototype, they said. The MIT chemists last year displayed their inexpensive, portable sensor that could detect gases emitted by rotting meat.
Developed by Timothy Swager, the John D. MacArthur Professor of Chemistry at MIT and his research student Sophie Liu, the device was one among many carbon nanotube devices that Swager’s lab has developed, including one that detects the ripeness of fruit.
MIT device works on the principle that carbon nanotubes can be chemically modified so that their ability to carry an electric current changes in the presence of a particular gas.
The sensor was tested on four types of meat: pork, chicken, cod, and salmon. They found that when refrigerated, all four types stayed fresh for 4 days and then began to decay at varying rates.