[Image above] The sensor adheres to fish skin and would help monitor the freshness of cargo. Credit: ETH Zurich; YouTube
For workers in the food industry, it can be challenging to constantly control and monitor the freshness of food from the farm all the way to the grocery store. This is especially important for food that requires constant refrigeration, such as meat, fish, and dairy products.
Disruptions in the food supply chain do happen. Meat can get exposed to oxygen, which can allow microbes to grow and cause food poisoning. Even produce has its challenges during transport.
Now, a new development for monitoring food quality could be the solution to keeping an eye on the state of perishable food.
Researchers at ETH Zurich have developed a thin sensor that can monitor food quality in real time. A team, led by postdoctoral researcher Giovanni Salvatore, has developed a biodegradable microsensor five times thinner than a human hair that can measure the temperature of the food it’s attached to.
The microsensor is 16 micrometers thick and consists of an electric filament made of magnesium, silicon dioxide, and nitride encapsulated inside a polymer made from corn and potato starch, according to an ETH Zurich news release. It attaches to food products and can actually be ingested, since it’s made of stuff that’s safe for human consumption. All materials comply with food regulations in Europe and the U.S.
Credit: ETH Zurich; YouTube
The researchers claim the sensor will operate for one day when completely immersed in water and dissolves completely in a 1% saline solution in a little over two months. It will also continue to work when bent or crumpled. Although making the polymer thicker will extend its operation, it would be less flexible, according to Salvatore.
Microsensors have been used in dozens of applications, including collecting data to monitor metal corrosion, characterizing emulsion stability in seawater, and checking for heavy metals in groundwater. They’re also being used in the Internet of Things by connecting objects to the internet to perform functional tasks and collect data. Scientists are also developing nanosensors for use in medicine, agriculture, and drug manufacturing.
If you recognize the smell of raw fish, you know it’s sometimes hard to tell when fish has gone bad. However, these microsensors could bring the Internet of Things into the food world. “In preparation for transport to Europe, fish from Japan could be fitted with tiny temperature sensors, allowing them to be continuously monitored to ensure they are kept at a cool enough temperature,” Salvatore states in the release.
He also believes the microsensors will eventually become ubiquitous. But more research is needed to find a biocompatible energy source to power the sensor as well as integrate a battery, processor, and transmitter.
The paper, published in Advanced Functional Materials, is “Biodegradable and Highly Deformable Temperature Sensors for the Internet of Things” (DOI: 10.1002/adfm.201702390).
Watch the video below to learn more about the sensors.
Credit: ETH Zurich; YouTube
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