Inhibitor activities of two Lactobacillus strains, isolated from sourdough, against rope-forming Bacillus strains

The effect of two different sourdoughs, produced with Lactobacillus plantarum LMO25 and Lactobacillus alimentarius LMO7, with antimicrobial activities on inhibition of rope-forming Bacillus strains in wheat bread was studied. Addition of 15% or 20% low pH (pH 3.5–4.0) sourdough to bread dough, which were produced by using two strains (Lb. plantarum LMO25 and Lb. alimentarius LMO7) separately, prevented the generation of visual rope caused by Bacillus subtilis and Bacillus licheniformis. However, adding 10% sourdough was not enough to prevent the generation of visual rope. When repeated with sourdoughs with a higher pH (pH > 4), additives at 10% or 15% did not prevent the generation of rope, whereas additives at 20% prevented the generation of visual rope caused by both B. subtilis and B. licheniformis.