Milk Adulteration Testing and Analysis (MATA) kit for rapid detection of cow milk adulterated with urea and glucose at low cost

Abstract

Elevated levels of urea cause kidney and liver function problems, while elevated glucose has been the cause of raising the risk of diabetes in humans. These reasons determine that urea and glucose are of considerable interest in clinical analysis, agro-food chemistry, the dairy industry, and environmental monitoring. ProTox–III software was used to predict urea and glucose toxicity in humans. The colorimetric kit and Fourier-transform infrared spectroscopy were used for preliminary detection and confirmation of urea and glucose in cow milk. The outcome of this study was the development of a point-of-care MATA kit for urea and glucose detection in cow milk. To make the kit, the enzyme immobilization technique was used to coat urease and glucose oxidase-peroxidase enzymes on individual 8 well-polystyrene strips. The biochemical methods of Berthelot assay and Glucose oxidase-peroxidase assay were used to detect urea and glucose, respectively. The toxicity prediction results revealed that urea had an LD50 value of 6350 mg/kg and 23000 mg/kg for glucose. The colorimetric kit helped understand the presence of urea and glucose by change of color in the samples, and the developed MATA kit could detect 1.5 µg of urea and 3 µg of glucose from the cow milk. The shelf life of the urea kit was ~ 30 days, with 15 times the reusability of a single well, whereas that for the glucose kit was ~ 15 days, with the reusability of each well up to 7 times. The overall detection efficiency of the MATA kit was 85–90%.