Novel system to detect bacteria in real time in aquatic environments

Bacteria tests are conducted for quality control in many different industries. However, the cultivation method takes a long period of time to obtain results and there are more than a few bacteria that are difficult to cultivate. We have focused on the autofluorescence substance in the bacteria to detect them, and developed a sensor to measure the bacteria in real-time, without any pretreatments or addition of any reagents. This system uses a 405nm laser focused on the sample flowing through the flow-cell in order to detect the fluorescent light from the bacteria as well as scattered light. Fluorescent light and scattered light are separated by a dichroic mirror, and the number of viable particles (bacteria) and that of non-viable particles are obtained. We tested this system using fluorescent polystyrene latex particles and several bacterial strains, and confirmed that it had good detection capability. We believe that this system will become a next-generation bacteria detection system and help the introduction of PAT (process analytical technology) to all areas where real time and on-site detection is needed.