Epifluorescent Method for Detection of Nonviable Yeast. L. M. King, D. O. Schisler, and J. J. Ruocco, Adolph Coors Co., Golden, CO 80401. J. Am. Soc. Brew. Chem. 39:0052, 1981.

An epifluorescent method for assessing yeast viability utilizing a protein-staining fluorochrome, the magnesium salt of 1-anilino-8-naphthalene sulfonic acid (Mg-ANS), is described. This method was evaluated against two standard brewery methods for determining yeast viability, specifically the brightfield dye method utilizing methylene blue, and the slide culture method. Results indicate that the Mg-ANS method is simpler, quicker, and as accurate as the slide culture technique and more accurate than the methylene blue method when assessing yeast cultures of low viability. An alternate viability method using acridine orange and nalidixic acid was also attempted, but was less consistent.

Keywords: Fluorescence, Methylene blue, Mg-ANS, Viability, Yeast