Selection of Lactobacilli with Probiotic Properties

Z. R. DENKOVA, I. D. MURGOV and Al. K. SLAVCHEV
University of Food Technologies, Dept. of Organic Chemistry and Microbiology, BG - 4002 Plovdiv, Bulgaria

Abstract

DENKOVA, Z. R., I. D. MURGOV and Al. K. SLAVCHEV, 2006. Selection of lactobacilli with probiotic properties. Bulg. J. Agric. Sci., 12: 689-706

The aim of the present work was to select strains from genus Lactobacillus with properties, allowing their inclusion in probiotics and probiotic foods - survival in model conditions of digestion, high antimicrobial activity and resistance to some of the applied in medicinal treatment antibiotics. The resistance of lactic acid bacterial strains against different concentrations of bile salts, low and neutral values of pH and presence of pepsin was studied. It was shown that they survive at low (pH 2.0) and neutral (pH 7.0) pH values and pepsin and overcome the bile barrier. The antimicrobial activity against conditional pathogens, toxicogenic and pathogenic bacteria and enterobacteria was investigated according to the agar diffusion method. The highest activity exhibited Lactobacillus acidophilus and Lactobacillus delbrueckii ssp. bulgaricus. The resistance of the lactobacilli against most of the antibiotics, used in medicine was investigated. It was shown that the antibiotic resistance is strain specific. As a result of the conducted investigation were selected Lactobacillus strains, which conform to the requirements for probiotic cultures.

Key words: Lactobacilli, probiotics, artificial gastric juice, antibiotic resistance, antimicrobial activity