NEW METHOD FOR COUNTING THE BACTERIAL CONTAMINANTS OF BREWERS' YEAST

Abstract
Counts of the contaminating bacteria of brewery pitching yeasts, fermenting beers and storage beers have been difficult to obtain by methods other than direct microscopic observations because of the similarity in growth requirements of brewers' yeast and some of the contaminating bacteria. The antibiotic, actidione, inhibits the growth of brewers' yeast on culture media but does not interfere with bacterial growth. Actidione is thermostable and its activity against yeast is not affected by the usual ingredients of culture media. This antibiotic should, therefore, become a very useful tool for brewing bacteriologists.