Safety Assessment of Dairy Microorganisms, Streptococcus thermophilus and Lactobacillus bulgaricus, Isolated from Traditional Yoghurt Cultures

Abstract

The traditional fermented food consumption has become very popular because of the increasing public concern about food additives. Lactic Acid Bacteria (LAB) species have traditionally been used as starter cultures in the production of fermented food. LAB can acquire antibiotic resistance from other bacteria in the natural environment and different resistant mechanisms via mutation. The resistance of bacteria to antibiotics is an increasingly important public health problem worldwide. In this study, antibiotic resistance of 115 Streptocoocus thermophilus and 35 Lactobacillus bulgaricus isolates obtained from traditional Turkish yogurts were tested against kanamycin, chloramphenicol, erythromycin, ampicillin, rifampicin, tetracycline, vancomycin and gentamicin using disc diffusion method. Study results showed that most strains were susceptible to all the antibiotics tested while a few of them were determined to be resistant only to kanamycin, ampicillin, erythromycin, and tetracycline. When contacted in a human body, resistant strains might transfer the related genes to the pathogenic species, which may result in devastating consequences.