Fluorescence microscopy

Microscopy where specimens are lit with UV or blue light, making them emit longer-wavelength light. In food microbiology and quality control it is used to detect and identify microorganisms, foreign particles and fluorescent adulterants, often with cell-bound fluorescent labels for specificity. Epifluorescence microscopes with filter cubes for dyes like acridine orange let analysts count total bacteria in milk within minutes, distinguishing cells from debris. Immunofluorescence tags specific pathogens with labelled antibodies, and fluorescent in-situ hybridisation identifies spoilage organisms directly in biofilms on equipment surfaces.