IIT Guwahati team develops milk quality testing kit

How fresh is the milk that you consume every day?

​A team of researchers of IIT Guwahati have come up with a paper-based sensor that promises quick detection of freshness and quality of milk.

The research team led by Pranjal Chandra, an assistant professor, department of Biosciences and Bioengineering, IIT Guwahati along with Kuldeep Mahato, a research scholar developed a simple visual detection technique to detect the quality of milk, without the need for special equipment and instruments.

"The quality and freshness of milk are decided by the invasion and presence of microbes in the milk. Bacteria and other microbes that can grow in milk can not only affect the taste and freshness, but can also result in health issues. Pasteurization is commonly used to kill the microbes in milk and various tests are used to ensure the effectiveness of pasteurization. Commonly used tests such as the methylene blue test, are time consuming; it could take many hours for colour changes to indicate presence and absence of microbes. Commercial phenol-based tests require sophisticated spectrophotometers and involve multistep procedures. The portable kit and easy to operate sensor will make the process easy and quick," said a statement quoting Chandra.

Chandra said Alkaline Phosphatase (ALP) is a metalloprotein found naturally in raw milk samples and is considered an important biomarker in quality control of milk.

"It is found in raw milk and is destroyed during pasteurization. ALP is also found in higher amounts in the case of milk derived from animals with infection in the mammary glands. Detection of ALP in milk can thus point to inadequate pasteurization and perhaps contamination," it said.

The researchers successfully tested milk obtained from villages and commercially available milk samples using their paper-based sensor kit and found that they could detect down to 0.87 units of ALP per millilitre of milk to about 91 to 100% accuracy.

The work has recently been published in the journal, Biosensors and Bioelectronics.

The team has also developed a miniaturized detection kit and demonstrated the instrument-free, in-kitchen applicability of the kit for milk monitoring. This new sensor has been developed by Kuldeep Mahato, Ashutosh Kumar and Buddhadev Purohit.