Application of electrical admittance measurements to the quality control of milk

The method of electrical admittance spectroscopy has been used to study the water and fat content of milk. Over the frequency range 5 Hz to 1 MHz, the electrical circuit was dominated by a single time constant. To eliminate the effect of electrode polarisation, the conductance of the milk was measured at high frequencies where it showed a saturation value. The characteristics at 100 kHz and 8 °C for all milk samples revealed a linear decrease in conductance with increasing water content. Admittance data for full fat, semi-skimmed and skimmed milk showed an increase in milk conductance with decreasing fat content.