New method for detecting adulterants in milk
Researchers at the Indian Institute of Science (IISc) in Bengaluru have devised a low-cost and effective approach for detecting adulterants in milk by analysing deposition patterns after evaporation. The method was used to test for the presence of urea and water, the most prevalent adulterants, and the researchers believe it can be expanded to other adulterants as well.
Milk adulteration is a critical topic in developing countries such as India, where a considerable portion of supplied milk fails to meet the Food Safety and Guidelines Authority of India's standards. Water and urea are regularly added to enhance the amount of milk, making the watered-down version whiter and foamier – this can potentially jeopardise the normal functioning of the liver, heart, and kidneys.
The researchers focused on evaporative deposition patterns, which form when a liquid mixture, such as milk, entirely evaporates, causing volatile components to dissipate and solids or non-volatile components to organise themselves in different patterns. The evaporation patterns of milk with and without water or urea were considerably different.
The evaporative pattern in pure milk was a central, uneven blob-like shape. Water was discovered to produce distortion or complete loss of this characteristic pattern, depending on how much was added. The centre pattern is also entirely erased by urea. Because it is a non-volatile chemical, it does not evaporate but rather crystallises, beginning at the centre of the milk drop and spreading outward.
Lactometers, for example, search for changes in the freezing point of milk to identify the presence of water, although they have limits. The freezing point approach, for example, can detect water only up to 3.5 percent of the total milk concentration. Furthermore, while high-sensitivity biosensors for testing urea are available, they are expensive, and their accuracy tends to deteriorate over time. Using pattern analysis, the IISc team was able to detect water concentrations as high as 30% and urea amounts as low as 0.4 percent in diluted milk.
Dr. Virkeshwar Kumar, a post doctoral researcher, and Susmita Dash, an Assistant Professor in the Institute's Department of Mechanical Engineering, developed the technique. They reported on their findings in the journal ACS Omega.
The test does not necessitate the use of a laboratory or any other specialised procedure. "It can be done everywhere." "It is simply adaptable for use in remote and rural regions," Dr Kumar stated.
He and Dr. Dash feel that this technology might be expanded to test for adulterants in other beverages and products as well. "The pattern you receive is quite sensitive to what you put to it." As a result, I believe that this technology can be utilised to detect contaminants in volatile liquids. "It will be interesting to see how this technology is applied to items like honey, which is frequently falsified," Dr. Dash said.
They remarked that the method's simplicity may lend itself to straightforward automation once the patterns for adulterants and their combinations are established. These might be loaded into image analysis software, which would compare a snapshot of the sample's evaporative pattern – even one taken with a mobile phone – with other standard patterns to precisely determine the adulterants present.
"The next stage is to test for adulterants such as oil and detergents that generate an emulsion similar to milk." "We intend to continue working in this direction, building a reservoir of patterns corresponding to varying concentrations of different adulterants," Dr Dash said.