Effectiveness of Soy Milk as Food Carrier for Lactobacillus Acidophilus.

Three mild-fermented milk beverages prepared from soy milk and cow's milk were compared for their ability to preserve the cell viability of Lactobacillus acidophilus during refrigerated storage, in associative growth with Lactobacilus casei and Streptococcus thermophilus . The highest survival rate was obtained by using soy milk as substrate. The presence of L. casei in the starter culture had no influence on the viability of L. acidophilus , while the streptococcal cells showed a harmful effect. The culture activity measured as proteolysis and acid production remained fairly constant during the shelf life, despite the variations in colony counts observed for the different fermented milks analyzed.