ONE GRAD STUDENT’S INVENTION HAS THE POWER TO REVOLUTIONIZE FOOD WASTE – ALL FROM A SENSOR SMALLER THAN A BAND-AID.
A significant amount of food is wasted every year, but what if there were an affordable technology that could give a much closer sense to how far food is from spoiling than a freshness date? A tiny pH sensor may hold the answer.
“The pH sensors have long been used commercially, but ours is small, disposable and flexible to be integrated with circuits – and much cheaper,” says Khengdauliu Chawang ’24, a Ph.D. student in electrical and computer engineering at the Lyle School of Engineering who developed the sensor. “The ones presently in the market, I would estimate, cost $100 to $2,000.”
Higher pH levels mean food is increasingly moving toward going bad, but not all foods have the pH, she explains. “Fruit juice, for example, is usually more on the acidic side,” Chawang says. “The biggest challenge for this is that pH sensors are very calibration-dependent, so they need to adjust, for example, to viscosity. Even liquid-based foods have different viscosities.”
The idea of the sensor, which is 10 millimeters wide and 2 millimeters in length, is that when it passes different points in food distribution, the pH level could be tracked to monitor its present freshness. The sensor has been tested successfully thus far on fish, berries and many liquid-based foods. Chawang saw firsthand the effects of food waste growing up in Nagaland, India, and hopes the sensor will improve the situation globally. “This is something thatmaybe can contribute to many communities hurting in the world,” she says. “Wasted food has sad consequences.”
There are other potential applications, as well. One is research in electronic bandages.
“The idea here is to integrate sensors to study wound status because a wound condition is also directly correlated with pH level,” Chawang says. “If a wound is healed, then the pH level gets more acidic.”
Another potential application is to monitor sepsis, a large, potentially life-threatening response to infection.
“The blood becomes infected and spreads throughout. The problem with today’s medical diagnostics is the diagnosis is usually too late because it has spread over your muscle and tissue and your entire body is infected with virus,” she says.
“There are indicators in research that show blood pH level changes before it spreads into your tissue – the sensor could possibly make a difference before it’s too late.”