Investigation of the probiotic properties and the acid production rate of strains Lactobacillus delbrueckii ssp. Bulgaricus

The antimicrobial activity of strains Lactobacillus delbrueckii ssp. bulgaricus MG1, Lactobacillus delbrueckii ssp. bulgaricus MG2, Lactobacillus delbrueckii ssp. bulgaricus MG3 and Lactobacillus delbrueckii ssp. bulgaricus MG4 has been investigated against pathogenic microorganisms Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 8739, Listeria monocytogenes, Salmonella sp. by the agar well diffusion method.  The biomass, the culture medium and the cell-free supernatant were tested. The antibiotic resistance of the strains against clinical practice antibiotics with different mechanisms of action has been determined. The maximum specific growth rate and the parameters of the respective models for the selected strains was determined. The experiments established that Lactobacillus delbrueckii ssp. bulgaricus MG 3 exhibits the most pronounced antimicrobial activity compared to the other strains tested. Practical applicationsThis study was called for by the need to produce starter cultures with established purity and activity for use in the food industry. The aim of this work is to investigate a certain group of lactic acid bacteria widely used in practice and in the composition of starter cultures.