Tolerance of probiotic microorganisms to sodium chloride

Since the increasing consumption of packaged and ready-to-eat foods leads to excessive sodium intake, this study aims to investigate the effects of various sodium concentrations on probiotic microorganisms, which are key members of the human microbiota. A total of 5 probiotic microorganisms (3 different Lactobacillus plantarum (L. plantarum) strains, Lactobacillus kefiri (L. kefiri), Lactobacillus acidophilus (L. acidophilus)) were used in the present study. In order to find out the impact of varying concentrations of sodium chloride (1%, 2%, 6%, and 10%) on probiotic microorganisms viability, the formed colonies on de Man Ragosa Sharp (MRS) agar were assessed by plate count. Bacterial growth curves were prepared according to the visible colonies on the plates. It was found that, Lactobacillus acidophilus ATCC 4356 demonstrated significantly higher tolerance to sodium, particularly at the concentrations of 6% and 10%. In contrast, all of the L. plantarum strains exhibited limited tolerance at higher concentrations. The survival rate of L. acidophilus and L. kefiri at high concentrations of sodium for extend time is promising in order to develop new probiotic preparations in the pharmaceutical industry.