Bicarbonate inhibition of Saccharomyces cerevisiae and Hansenula wingei growth in apple juice.

The ability of sodium bicarbonate to inhibit growth of Saccharomyces cerevisiae and Hansenula wingei in apple juice was investigated. Sodium bicarbonate at concentrations of 0.06, 0.12, and 0.24 M was added to pasteurized apple juice that was then inoculated with 10(3) or 10(5) cfu/ml of either yeast. Growth of both yeasts was inhibited by 0.12 M sodium bicarbonate when incubation was at 4 degrees C; 0.24 M sodium bicarbonate caused a slow die off of yeast. At 18 degrees C, H. wingei became more sensitive and died in the presence of 0.12 M sodium bicarbonate, but S. cerevisiae became resistant to 0.24 M sodium bicarbonate. These results could not be attributed to bicarbonate-induced pH elevation or sodium. Potassium and ammonium bicarbonate were also inhibitory, implicating bicarbonate ion as the antimicrobial agent.