Metabolic Properties, Functional Characteristics, and Practical Application of Streptococcus thermophilus

The lactic acid bacteria (LAB) are a group of Gram-positive, non-respiring, non-spore-forming bacteria, cocci or rods, which produce lactic acid as the solely or main end product of carbohydrates fermentation. Some strains of LAB are probiotics that play important role in food processing and safety, as well as in maintaining human health as an integral part of the microbiota, that could be widely found in fermented foods, such as yogurt, cheese, kimchi, and wine. Streptococcus thermophilus, a species of LAB, exhibits probiotic effects, including alleviation of lactose intolerance, chronic gastritis, diarrhea, and bacteriostatic effects on pathogens. Recently, S. thermophilus in fermented products has attracted increasing research interest. However, the sources of new isolates of S. thermophilus are limited, so it is necessary to screen a large number of diverse habitats and functionally enriched selection to discover new and useful strains. This review summarizes the results related to insulation and identification, safety assessments and metabolic properties of S. thermophilus. Functional properties, its application in the production of fermented products, the development of new perspectives, as well as shortcomings are discussed in detail, in order to facilitate future research and application of S. thermophilus.