The purpose of our research is to develop a novel analysis technique. It is used for food safety control system and able to rapid separation, identification and quantification of microorganism. A three dimension dielectrophoresis (DEP) chip is developed with rapid separation and detection functions. Due to the low bacteria concentration (about 103∼ 105/ml) in fresh milk, a novel design is used for trapping the target bacteria in the specific area, which the unique design can easily combined to Raman spectroscopy and bacteria can be identified via its specific fingerprinting. This integrated chip completed bio-particle separation, trapping, concentration and detection in continuous flow. Bacteria strain and population can be detected in our 3D DEP chip within 3 minutes.