The proposal aims at the fast detection of three pathogens, namely Salmonella spp, Escherichia coli, and Bacillus cereus in milk, and one spoilage bacteria (Alicyclobacillus acidoterrestris) in juice samples using Mach-Zehnder interferometer (MZI) arrays integrated on silicon chips. Currently, the detection of these bacteria is performed through multi-step and time-consuming procedures (at least four days). The project will target the simultaneous immunochemical detection of these bacteria at very low concentrations after a few hours enrichment through functionalization of individual MZIs of a single chip with bacteria-specific antibodies. Furthermore, especially for Alicyclobacillus acidoterrestris, for which there are not commercially available antibodies, a rabbit polyclonal antibody will be developed and evaluated for its immunochemical determination. In addition, through improvements in sensor and fluidic design, stabilization of the immobilized onto MZIs immunoreagents and implementation of different signal enhancement approaches high detection sensitivity and suppression of the analysis time will be pursuit.