The influence of various fermenting conditions using Saccharomyces cerevisiae, alone (Control, Single) and in combination with mixed lactic acid-producing bacteria (Combined 1, Mixed, Combined 2), including Bifidobacterium longum, Enterococcus faecium, and Lactobacillus acidophilus on flour sourdough preparation was examined. For the Combined 2 method, starters were incubated separately for 15 h, combined, and then further incubated for 10 h. Fermentation using Combined 2 improved the growth of mixed lactic acid-producing bacteria, but inhibited that of S. cerevisiae. This was also reflected in the extent of the pH reduction in sourdough produced in the Combined 2 step by these organisms. Among biochemical activities, $CO_2$ production and titratable acidity were increased by Combined 2, although the viable yeast counts were decreased. Aroma compounds in sourdough markedly varied according to fermentation conditions.