Instability of Lactobacillus acidophilus in Yogurt

Abstract

L. acidophilus added to yogurt decreased in numbers during refrigerated storage. This instability was caused by substance(s) produced by L. bulgaricus, a component species of yogurt cultures. H2O2 produced by L. bulgaricus during the manufacture and/or storage of yogurt appeared to be the main substance responsible for the antagonism of L. bulgaricus toward L. acidophilus since added catalase reduced the antagonism.