Specific optical-based biosensor to rapid detection of Salmonella Typhimurium using FTIR: evaluation in natural orange juice, as an application in food products

Salmonella is one of the main pathogenic microorganisms present in foods, where natural orange juice is an example, although there are techniques that determine this bacterium, it is necessary to develop a device that allows Salmonella detection quickly, easily, and in real time. Therefore, using biosensors is an excellent option to solve this need. In this work, an optical biosensor of amorphous silicon thin films, a non-studied material in this area, was applied for the detection of Salmonella Typhimurium in natural orange juice, using Fourier transform infrared spectroscopy. The characteristic detection infrared band was identified at 1030 cm^-1, related to the functional groups presence of the cell membrane and DNA bacterial, Salmonella concentrations in a range from 100 to 1000 CFU/mL were detected, and a SEM analysis was carried out. Biosensor did not show cross reactivity with enteropathogenic Escherichia coli.

Keywords: biosensor, amorphous silicon, Salmonella, FTIR, orange juice.