The project concerns the development of a demonstrator for a small size portable low-cost device for detection of E. coli bacteria using a Long Period Grating Fibre Sensor (LPGFS). LPGFS operation is based on detection of ambient (where the LPGFS is placed) refractive index variation induced by the presence of E. coli bacteria. The demonstrator has a small volume measuring chamber where liquid phase sample, suspected to be infested with E. coli bacteria is placed. It consists of a Sensor Interrogation Module (SIM - LPGFS and Optoelectronics) and a Data Acquisition and Processing Unit (DAPU). The design will take into account three possible variants: LPGFS cladding refractive index is larger, equal or lower than that of the ambient surrounding the fibre sensor. Short determination time (5 – 10 min) is a major advantage of the project. The device based on LPGFS can be used for other types of pathogenic bacteria strains or chemical substances present in gaseous or liquid phase sample. The project will increase SME industrial capacities and business perspectives by establishing transnational co-operation.