Probiotics are live microorganisms that, when given in sufficient proportions, provide a health benefit to the host. Lactic acid bacteria and bifidobacteria are the most common microorganisms used as probiotics, however other bacteria and yeasts are also employed. It is critical to emphasise that probiotics have strain-specific biological effects, and that the success or failure of one strain cannot be generalised to another. As a result, effective strain detection using cutting-edge molecular and computer-based methods is critical. 16S rRNA gene sequence analysis and DNA-DNA hybridisation procedures can be used to identify species. Various reproducible genetic approaches or unique phenotypic features can be used to further identify strains. In vitro research is used to gain knowledge of probiotic strains as the first stage.