Colorimetric Detection of Milk Adulteration Using a Paper Test Card

Milk is one of the essential foods for humans as it has various nutritious elements. Milk is a colloid consisting of 80–90% water and protein, vitamin, carbohydrate, and many more solid contents. On the other hand, many harmful chemicals are added to milk to increase its shelf life, solid, not fat content, etc., without considering the negative effect on the consumers. Taking these aspects into account, an easy process has been developed to detect a few adulterants which are added to milk, such as hydrogen peroxide (H2O2), detergents, salts, and sodium carbonate. Using a paper test card integrating with an image colorimetry, the method has been developed. The images of the detection zone were captured in a camera, followed by finding the color intensity using a free application software the amount of added adulterants have identified. This method requires only a drop of reagent and a drop of sample to perform the adulteration test. It is a fast, facile, low-cost, and easy-to-use method. The limit of detection (LOD) for these adulterants has been found within 0.2 % (v/v). The recovery percentage of detecting added adulterant concentrations using the method is found within the range of 91–105 %.