As a common probiotic, lactic acid bacteria must be able to withstand gastric acidity and intestinal bile salts and survive in the human body in large amounts. Nowadays, most studies concerning the mechanism of acid resistance of lactic acid bacteria are focused on the theory of proton pump and alkali production. In addition, the contents of exogenous substances such as glucose, amino acid and fatty acid have a certain effect on its tolerance. The mechanism of inhibition lactic acid bacteria under bile salt stress mainly involves bile salt hydrolase, stress protein and the self-protection ability of its cell membrane. This article reviews the existing literature on the mechanism of acid and bile salt resistance of lactic acid bacteria. The second aim of this review is to explore the factors affecting the acid and bile salt resistance of lactic acid bacteria.

The probiotic effects of lactic acid bacteria (LAB) depend on their tolerance to the human gastro-intestinal tract. The acid and bile salt tolerance of four exopolysaccharide-producing strains of Lactobacillus plantarum was examined by the measurement of optical density at 600 nm (OD600 nm) and the plate colony counting. The results showed that the strain F401④ had higher acid tolerance capacity, and F201⑥ had the highest bile salt tolerance capacity which showed more than 100% survival rate after culture for 4 h in the presence of 0.3 and 0.5 g/100 mL bile salt.