Then each 0.9 ml of the aseptic milk was blended with 0.1 ml of raw milk in the reaction cell containing Pt electrode as working electrode. The optimal voltage was assayed and input in the electrochemical measurement system. The optimal temperature was selected and set by a circulating water bath asso- ciated with the system. DT measured for each assay was loaded into the calibration graph of DT against microbial density to cal- culate the bacterial counts after being multiplied by the dilution factor.