According to a report on the German "Der Spiegel" weekly website on June 5, nearly one-third of the world's food was thrown into the garbage. Every year, Germans throw away 55 kilograms of fruits, vegetables, bread and meat. This is not only a waste of food, but also an adverse effect on the environment.
Researchers are now developing a sensor that can help identify meat and fish spoilage.
The instrument consists of a piece of paper and a tiny carbon electrode printed on it. Ferrat Judel of the Imperial College London and colleagues used the hygroscopicity of paper to create prototypes. They wrote in the professional journal "American Chemical Society Sensors": "Although the paper feels dry and looks dry, it is always wet." At 50% relative humidity, moisture accounts for about the total weight of the paper. 5%.
Scientists continue to write that by detecting the conductivity of the water film in the paper, it is known which substances are dissolved in it. If water-soluble gas is present in the surrounding environment, the conductivity of the paper will increase. Ammonia and trimethylamine produced when meat or fish are degraded are also water-soluble gases. The measurement results can be read by an application.
The researchers also integrated their sensors with near-field communication chips. This technology reads information by electromagnetic induction. When rotten gas is not detected in the paper, the researchers' application automatically pops up when the meat and fish are still edible, and if the food deteriorates, the application does not respond.
The researchers said that testing the packaged fish and chicken in the laboratory found that the sensor's test results were more accurate than the prior art. At the same time, the new system is priced at only 2 cents, which is very cheap. Moreover, the sensor is biodegradable and non-toxic. It therefore meets several key points that have previously caused problems when trying to develop similar sensors.
Judel and colleagues point out that the currently developed sensor is the first commercially available variant of its class. Mass production of such sensors is technically feasible. Scientists hope that food manufacturers and supermarkets will be able to introduce the instrument within the next three years.