Technological Performances of Isolated Heterofermentative Lactobacillus Alone or in Coculture with Isolated Streptococcus thermophilus

Technological performances of three bacterial isolates belonging to the family of heterofermentative lactobacilli: Lactobacillus brevis, Lactobacillus buchneri and Lactobacillus fermentum and one isolate belonging to the family of homofermentative lactobacilli; Streptococcus thermophilus on synthetic media and on milk cows have been studied. The results of this study did not highlight a synergistic effect; however, the acidification was improved in cocultures of S. thermophilus and Lb. fermentum in MRS lactose broth at 37°C. These studies indicated that the acidification of the added sucrose to the synthetic medium was mainly by the lactobacilli. This indicated that there was no improvement of the culture acidification by S. thermophilus. Cluster analysis of the sensorial assessment of the milk fermented by the pure or mixed cultures showed important organoleptic properties variations. The results carried out permit to suggest many technological performances that can be used by the dairy industries to produce new products or to improve the taste, color or texture of the existent products