U.S – A small pH sensor that can detect food spoilage in real time has been created by a researcher at Southern Methodist University (SMU).

Since the flexible pH sensor is only 2 mm long and 10 mm wide, it may be included in the current food packaging techniques.

Conventional pH meters are not ideal for inclusion in food packaging because they are significantly larger, measuring approximately 1 inch (in) long and 5 inches tall.

Chawang, who is originally from Nagaland where the populace mainly depends on agricultural crops, created the device out of a personal motivation.

“Food waste in Nagaland means undernourished children and extra fieldwork for the elderly to compensate for the loss.

“The need to prevent food waste motivated me to think of a device that is not expensive or labour-intensive to develop, is disposable and can detect freshness levels,” he explained.

According to the Food and Agriculture Organization (FAO) of the United Nations, roughly 1.3 billion metric tons of food produced around the world go uneaten every year. Nearly 40 percent of food – approximately 130 billion meals – is wasted in the United States, according to Feeding America estimates.

The pH sensors function similarly to wireless radio-frequency identification devices, such as those that are found in luggage tags to track checked bags at airports or inside identification cards that can be scanned, according to Khengdauliu Chawang, the SMU Ph.D. student who developed the technology.

The sensors might be scanned and data sent back to a server monitoring the pH level of the product each time a food package equipped with Chawang’s device passes a checkpoint, such as shipping logistics centers, harbors, gates, or supermarket entrances.

Chawang was awarded the Best Women-Owned Business Pitch award at the 2022 IEEE Sensors Conference by the Institute of Electrical and Electronics Engineers (IEEE).

She developed her invention with the help of J.-C. Chiao, Ph.D., the Mary and Richard Templeton Centennial Chair and professor in the Lyle School’s Electrical and Computer Engineering Department at SMU.

The system would enable reliable detection of freshness limitations throughout the whole food supply chain as well as continuous pH monitoring.

The pH levels are directly related to the freshness of the food. More specifically, because fungus and bacteria flourish in high-pH settings, food with a pH level greater than normal indicates spoiled food.

Hence, abrupt pH changes in food storage during production and delivery may be an indication of potential food spoilage.

Chawang’s device uses electrodes to measure pH levels based on the quantity of hydrogen ions present in an item or solution.

Since hydrogen ions are electrically charged molecules, the electrodes inside the pH sensor can detect the electrical charge produced. The level of hydrogen ions may then be converted to pH values using what is known as the Nernst Equation.

Further studies are now being conducted on the pH sensor, which has been successfully tested on foods like fish, fruits, milk, and honey.

A limited number of biocompatible components are used to create the technology, which is printed on flexible films.

The manufacturing of the disposable sensors is low-cost and does not require a semiconductor cleanroom setting.

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