Nagaland Scientist in US Develops Tiny, Inexpensive Sensor To Detect Spoiled Food

NEW DELHI: An Indian researcher in the US has developed a sensor that can tell in real-time when food has spoiled. The small and low-cost acidity sensor will help address a key health concern in a cost- effective manner.

Khengdauliu Chawang, hailing from Nagaland and a PhD student at Southern Methodist University in Texas, US, has created the device to detect food spoilage in real time.

The flexible pH or acidity level sensor is only two millimetres in length and 10 millimetres in width, which will make it possible to include the device in current food packaging methods, such as plastic wrapping.

Typically, industries use much bulkier devices, measuring roughly one inch long by five inches tall, to calculate pH levels or to tell how acidic or basic the food is. This does not make them suitable to be included in every package of food to monitor its freshness in real-time.

Device- creator Khengdauliu Chawang explained that the pH sensors they developed work like a small wireless radio-frequency identification device -- similar to that found inside a luggage tag after it has been checked at airports.

"Every time a food package with our device passes a checkpoint, such as shipping logistics centres, harbours, gates or supermarkets' entrances, they could get scanned and the data could be sent back to a server tracking their pH levels," Chawang said in a statement released by the university.

Chawang said that such configuration would allow continuous pH monitoring and accurately detect freshness limits along the entire journey -- from farms to consumers' houses.

Roughly 1.3 billion metric tonnes of food produced around the world go waste every year, according to the Food and Agriculture Organization of the United Nations,

Creating the device has a personal meaning for Chawang, who is originally from Nagaland in India’s northeast, where the population relies heavily on agricultural crops.

Chawang elaborated, "Food waste in Nagaland means undernourished children and extra fieldwork for the elderly to compensate for the loss."

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

Food waste not only contributes to food insecurity and lost profits for food manufacturers, but such wastage is also bad for the environment, the researcher noted.

According to Chawang, food freshness level is directly correlated to pH levels, For example, food with a pH level higher than the normal range indicates spoiled food, as fungi and bacteria thrive in high-pH environments.

Possible food spoilage can be indicated by sudden pH changes in food storage during production and shipping, she said.

The concentration of hydrogen ions found in a substance or solution can measure the pH level.

The latest pH sensor has successfully been tested on food items like fish, fruits, milk and honey, Chawang said. The sensor is made with a very small amount of biocompatible materials and uses printing technologies on flexible films.

"The entire process is similar to printing newspapers. The processing does not require expensive equipment or a semiconductor cleanroom environment. Thus, the costs are low and make the sensor disposable," added JC Chiao, a professor at SMU, who helped in the development of the device.

Big Ideas competition at the 2022 IEEE Sensors Conference organised by the Institute of Electrical and Electronics Engineers (IEEE) honoured Chawang with the Best Women-owned Business Pitch for her invention, the university added.

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