Food waste is a common problem in modern culture. An environmental impact is caused by the estimated 88 million tons of food waste that is produced annually in the European Union. Foods derived from animals have a negative effect. Food quality is impacted by freezing and thawing because when meat is repeatedly frozen and thawed, it can increase the number of pathogenic germs. By greatly extending the shelf life of food, especially meat, freezing significantly lowers waste while maintaining food quality and safety. The temperature of food containers is measured by frequently used temperature sensors in the food supply chain, e.g., refrigerators.

An edible device made by scientists at the Istituto Italiano di Tecnologia in Italy. The device can detect whether a frozen item has been thawed and then refrozen. Ivan Ilic, Mario Caironi, and their colleagues’ research, titled “Self-Powered Edible Defrosting Sensor,” was published in the journal ACS Sensors.

By joining an ionochromic cell and a temperature-activated galvanic cell, the gadget is able to recognize defrosting events. Table salt, red cabbage, and beeswax are just a few of the perfectly palatable elements used to make the sensor’s components. The aqueous electrolyte solution is used to power the galvanic cell, and it can only generate current at temperatures higher than its freezing point. The defrosting current is used by the ionochromic cell to liberate tin ions. This interacts with natural dyes to generate compounds that change color and reveal information about defrosting activities. For instant visual recognition, this device mostly uses a color shift as its signal.

The sensor’s response temperature can be adjusted between 0 and 50° Celsius. The temperature range enables it to be utilized in the supply chain. As a sensor, it can measure the amount of time that an object was exposed to above-the-threshold temperatures, and as a detector, it may indicate that such exposure occurred. The device could ensure that frozen food is handled correctly and is safe for consumption. The sensor could be used by workers in the supply chain as well as consumers, ensuring that the food was properly frozen during the whole supply chain.