Measurement of Low Levels of Yeast Contamination in Beers and Wines

Saccharomyces acidifaciens, S. oviformis, S. rosel and S. steineri were isolated frequently from sound and spoilt red, rosé and white wines. Addition of as few as 4 cells of these species to samples of sterile-filtered wines resulted in eventual spoilage. A method based on the presumptive coliform count in the bacteriological analysis of water is suggested for the detection and enumeration of small numbers of yeast cells liable to cause spoilage of wines and beers. The method compares favourably with other methods of assessment of microbial populations.