The era of "best before" dates may soon be a thing of the past, as chemists inch closer to developing smart labels that can tell you when your food has gone bad.
Researchers at Clarkson University have developed low-cost, portable, paper-based sensor labels that they hope will be able to detect food spoilage, authenticate tea and wine, and even identify new medicinal plants in remote jungles. These results were shared at the 254th National Meeting & Exposition of the American Chemical Society, the world's largest scientific society, last Tuesday.
"I've always been interested in developing technologies that are accessible to both industry and the general population," lead researcher Silvana Andreescu said in a press release. "My lab has built a versatile sensing platform that incorporates all the needed reagents for detection in a piece of paper."
A reagent a substance or mixture for use in chemical analysis, like the kits used to measure the chlorine levels in a pool. Andreescu's paper test can measure different toxins, and the intensity of the colors that come up on the sensors indicate the concentration of the analyte, which indicates spoilage or other factors.
This is easier than most of the other paper sensors being developed, and, practically speaking, means that users wouldn't have to add any other chemicals to the test—just the analyte they wish to measure. It also means that the paper sensors can be designed to detect a wide range of potentially harmful substances such as Ochratoxin A, a fungal toxin that can be found in coffee or cereal.
This technology is still largely in its developmental phase, though Andreescu has created a prototype that can successfully identify Ochratoxin A, and she says it's an encouraging step toward detecting more serious contaminants like salmonella and E. coli.
As far as food spoilage is concerned, these sensors would bind to the reactive oxygen species that rotting foods accumulate over time and would, for example, tell consumers when to throw out that yogurt that doesn't smell too bad but has been in their fridge for way too long.
Sure, we can already use our eyes to see mold or color changes, or our noses for the age-old smell test, but those methods are still prone to human error and lots of food waste, just like the confusing "best before," "use by," or "sell by" indications that are often seen as an imperative and not an estimation.
With these paper sensors, throwing out food would be more like using a high school chemistry kit—and would mean no more crossing your fingers after swallowing that one-dollar oyster.