Microbiological control of wine. The application of epifluorescence microscopy method as a rapid technique Original Research Article

In this study, epifluorescence microscopy (vital staining) was used for microbiological control of wine, the results being compared with plate counts of colony forming units (cfu). 4′,6-diamidino-2-phenylindole (DAPI) combined with propidium iodide (PI) were the fluorochroms used. The correlation between the two methods (plate counts and vital staining) was 0.52 and 0.83 for the control of finished and non-finished wines, respectively. According to the results obtained the vital staining with DAPI combined with PI, is trustworthy as a fast control for wine during the technological process, and it can be used by industrial wine producing units as an indicator of wine microbiological quality, with the consequent savings in time and money. For finished wines, the results obtained by the vital staining technique, were 103-fold higher than the ones obtained with the plate count method, which is in accordance with what should be expected, since under stressful conditions the number of metabolically active bacteria exceeds by far the number of culturable bacteria.