Evaluation of a commercial fluorochromic system for the rapid detection and estimation of wine lactic acid bacteria by DEFT

A commercial fluorochromic system was evaluated for the rapid detection of lactic acid bacteria in fortified wines by the epifluorescent filter techni que (DEFT). The viability test used, employing the fluorescence dyes SYTO 9 and propidium iodide, was able to detect and clearly differentiate viable from non-viable cells (killed with a 50% v/v ethanol solution). A good over all agreement (n = 0.92) was and the plate count in the range studied (5 x 10(2)-4 x 10(9) cells ml(-1)). Wine components which might otherwise interf ere with the method could be removed by including simple wash steps in the protocol. This measure proved critical to the success of the procedure. For practical purposes, the rapid method studied seems to be a good alternativ e to the traditional cultural methods as part of quality control programmes in wine making. It may also be useful when studying the efficacy of certai n treatments in the elimination of wine bacterial contaminants.