Detection of Listeria Monocytogenes in Milk Using a Laser Light Scattering Sensor System

This study reports the detection of foodborne pathogen (Listeria monocyto genes) in milk using the laser light scattering sensor system, bacterial rapid detection using optical scattering technology (BARDOT), and verifies the reliability of the system. The BARDOT mainly includes colony location finder system and light scattering capture system. To apply BARDOT for detection, the library of Listeria monocytogenes and non-Listeria monocytogenes should be established. After that, the laser light scatter patterns of the milk samples will be collected and the features of scatter patterns can be extracted after selecting the appropriate wavelet moments; therefore, the detected colony can be classified and analysed based on the established library. To validate the effectiveness of the presented technology, we test the colonies which have been detected by BARDOT using polymerase chain reaction PCR and real-time quantitative PCR (qPCR) methods. Meanwhile, we also investigated whether the cell wall protein expression of Listeria monocytogenes in different medium would affect the detection result of BARDOT. Results reveal that the BARDOT system can accurately detect Listeria monocytogenes in milk and will not be affected by culture medium, which provides a label-free, real-time detection method for Listeria monocytogenes.