Indian Institute of Technology Hyderabad Researchers are developing a Smart Phone-based sensors to detect adulteration in milk.
As a first step, they have developed a detector system to measure the acidity of milk through design of an indicator paper that changes color according to the acidity of the milk. They have also developed algorithms that can be incorporated on to a mobile phone to accurately detect the color change.
The research team has developed a sensor-chip based method for measuring pH, an indicator of the acidity and have used a process called ‘electrospinning’ to produce paper-like material made of nanosized (~10-9 m diameter) fibres of nylon, loaded with a combination of three dyes. The paper is “halochromic”, that is, it changes color in response to changes in acidity.
The Researchers have developed a prototype smart phone-based algorithm, in which, the colours of the sensor strips after dipping in milk are captured using the camera of the phone, and the data is transformed into pH (acidity) ranges.
They have used three machine-learning algorithms and compared their detection efficiencies in classifying the colour of the indicator strips. On testing with milk spiked with various combinations of contaminants, they found near-perfect classification with accuracy of 99.71%.
The research by a team of researchers comprising of Prof. Shiv Govind Singh, Department of Electrical Engineering, IIT Hyderabad, Dr. Soumya Jana and Dr. Siva Rama Krishna Vanjari, Associate Professors in the Department of Electrical Engineering, IIT Hyderabad and others, has been published in the November 2018 issue of Food Analytical Methods journal.
Speaking about the importance of this research, Prof. Shiv Govind Singh said, “While techniques such as chromatography and spectroscopy can be used to detect adulteration, such techniques generally require expensive setup and are not amenable to miniaturization into low-cost easy-to-use devices. Hence, they do not appeal to the vast majority of milk consumers in the developing world.”
Further, Prof. Shiv Govind Singh added, “We need to develop simple devices that the consumer can use to detect milk contamination. It should be possible to make milk adulteration detection failsafe by monitoring all of these parameters at the same time, without the need for expensive equipment.”
In the long run, the team hope to develop sensors for other physical properties such as conductivity and refractive index, and integrate it with the pH detection unit to obtain comprehensive milk quality check systems that can be easily deployed by the consumer using mobile phones and other hand-held devices.
The conventional way to detect adulteration in milk is to analyse the chemicals that are present in it by complex processes.
This research group will focus on detecting the contamination through sensing changes in the biophysical properties of milk.