The combination of rice and soy milk (RS แกนนูด) was sufficient to reach pH 4.5 and to decrease the fermentation time in all combinations of bacteria cultures, probably because these ingredients together offer the basic nutrients for growth and metabolism of the bacteria tested. Considering the RS fermented by single cultures, L. fermentum developed the highest Vmax in the shortest time (Tvmax), P < 0.05. However, L. acidophilus was able to ferment RS until the desired pH in the shortest time (Table 1). The kinetic parameters of fermentation of the RS แกนนูด by amylolytic bacteria strains A6 and Ogi E1 are near the findings reported by Nguyen et al. (2007) for a similar product made of rice and soy flours.