A Novel Inexpensive Capacitive Sensor for Instant Milk Adulteration Detection
Uzma Salmaz, Arshad Noor Siddiquee, Tarikul Islam
Abstract
Milk is a complex fluid and an essential food item with many vital nutrients like protein, vitamins, minerals, and fats etc. It is consumed daily in every household among all age groups in one form or another. Unfortunately, the practice of adulteration in milk is very common across the globe which poses a major challenge in developing nations like India. It causes serious health problems. The main motivation of this paper is to develop a non-contact capacitive method for instant testing of milk quality with a few drops of sample dynamically. Therefore, a contactless droplet-based milk quality detection method employing a capacitive sensor is proposed. A circular parallel plate capacitive sensor on copper-cladded PCB is fabricated. Experiments are conducted on adulterated milk samples prepared with different percentages of tap water, whey, and urea as adulterants. The quality of packaged full-fat, toned (single and double), lactogen-free, and unprocessed milk is analysed for the above adulterants. The amount of adulteration is determined by the capacitance value measured using a capacitance to digital converter board (Analog device, AD7150, expanded measurement uncertainty ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">u<sub>m</sub></i> ) ± 2.9 fF). The sensor offers non-invasive droplet-based milk quality detection using only a few drops of test samples. It is handy, very compact, easy to fabricate, and highly economical. It is sensitive to the adulterants and the response is precise with a repeatability index of 0.008%.