1-N-1 Sensor to Detect Whey Adulteration of Milk

Whey is added as an adulterant in to the pure milk to increase the volume of milk. In this study a rapid method has been developed to detect adulterated milk by adding liquid whey using a non-destructive sensing system that uses interdigital capacitive (IDC) sensors. We developed an advanced method using four 1-n-1 (1-1-1, 1-3-1, 1-5-1, and 1- 11-1) IDC sensors to detect liquid whey adulteration in pure full cream milk by fringing field emissions using coplanar electrodes. This IDC sensor measured this whey-mixed milk sample with a setup that incorporates a capacitance to digital converter and a microcontroller to display the digital output. This IDC sensor is fabricated on copper-cladded printed circuit boards (PCBs) due to its cost effectiveness, with 70% metallization ratio. The structure of an IDC sensor is analyzed using COMSOL Multiphysics software. We examined five different concentrations (10%, 20%, 30%, 40%, and 50%) of whey-adulterated pure milk in each 50 ml sample. The proposed sensor provides a promising tool for analysis of liquid whey in milk samples. All four sensors capacitance values exhibit a nearly linear correlation with milk's various levels of whey adulteration. The sensor is affordable, lightweight, easy to construct, and convenient. Both simulation and experimental methods have shown that Sensor 1-11-1 has the highest sensitivity.