Is this food starting to spoil? Food producers and distributors want to be able to answer few questions as much as they want answer that one. In the hope of making those answers easier to achieve, researchers from Nanjing University’s School of Electronic Science and Engineering as well as The University of Texas at Austin’s Materials Science and Engineering Program published a paper in The American Chemical Society’s journal Nano Letters in late June announcing the development of a wireless sensor device able to detect spoilage and communicate the food status to smartphones. Using a polymer-based gas sensor, they succeeded in achieving high sensitivities to compounds produced by decomposing organisms.
“Sometimes we cannot easily notice the slightly [spoiled] food by smell or vision and at this time a sensitive and precise electronic nose is much more reliable,” co-author Guihua Yu, PhD, tells Food Quality & Safety. “According to our research, we developed a highly sensitive material and our sensor is able to detect amines with low concentration of 5 ppm, which approximately corresponds to the early stage of food spoilage.”
Prof. Yu his colleagues worked with chemoresistive sensor technology, which he notes is different from the means used by University of Leicester researchers in 2016 in the development of their “electronic nose” capable of identifying ripe mangoes. That research relied on proton-transfer-reaction mass spectrometry.
Building on the technology of near-field communication (NFC) labeling that make possible contactless-payment systems and keycards, Prof. Yu and his collaborators developed NFC tags containing a switch that would detect food spoilage and communicate it to a smartphone. Their gas-based sensor was embedded into NFCs placed near meats that were stored for 24 hours in 86 degrees Fahrenheit, and was able to detect significant quantities of foul-smelling biogenic amines (BAs) released by the spoiling meat.
“The concept of using NFC technology to analyze food has been proposed for 3 to 4 years,” Prof. Yu explains. However, in most previous works, they did not really [develop] wireless detection with mobile phones. Traditional microbe-detection requires professional equipment and trained personnel. It takes time to process samples. Therefore, it does not appeal to the needs of portable, convenient, and precise detection for individual consumers, and is not cost-effective for detection needs in large quantities.”
Prof. Yu says that NFC-tag–based system means professional equipment and trained personnel are no longer necessary in detecting spoilage at an extremely early stage. For that reason, he expects his work will be applicable both to general consumers and to industry as a whole.
“It is much convenient and precise for consumers and also appeals to the detection needs in large quantities at the manufacturing level,” he says. ‘We anticipate this device could get ready for market in 2 to 3 years if all things go well.”