Direct Epifluorescence MicroscopyThe Direct Epifluorescent Filter Technique (DEFT) is a rapid method for enumerating bacteria. Used widely in the dairy industry for milk and milk products, it has also been applied to beverages, foods, clinical specimens and in environmental research. The technique involves capturing bacterial cells on the surface of polycarbonate membrane filters, staining with a fluorochrome such as acridine orange, and visualisation using epifluorescence microscopy. Enumeration of bacteria is greatly facilitated by image analysis and Perceptive Instruments has great expertise in DEFT and similar direct epifluorescence microscopy techniques. Semi-automatic enumeration of DEFT by image analysisThe high speed count and feature measurement capabilities of the Sorcerer image analysis system are ideal for the Direct Epifluorescent Filter Technique. Fluorescing cells are viewed in real time by Sorcerer's high sensitivity CCD video camera and viable & non-viable cells readily distinguished by virtue of contrast differences. Different parts of the membrane filter are systematically scanned with bacterial counts transferred directly to Microsoft Excel for customised data processing and reporting. |
