Quick lactobacillus acidophilus quantification in probiotics using real-time PCR

Abstract

Lactobacillus has a biological effect to supports digestion system. Therefore, it is widely used in dairy products such as yoghurt, food additives and pharmaceuticals. Lactobacillus acidophilus (L. acidophilus) is often used in fermented dairy products such as yoghurt and functional products. However, in Vietnam, there is currently no standard method for quantifying L. acidophilus. In this study, a quantitative method of L. acidophilus using real-time PCR based on a specific fragment of Hsp gene was developed. The limit of quantification of the method is 105 CFU/g/mL that is suitable for quality assessment of probiotic products with greater quality claims than 106 CFU/g/mL. The specificity of the method is of 100% when compared with nonspecific strains and repeatability is of Sr < 0.125 in accordance with the requirements of ISO 16140: 2005 and AOAC: 2016 annex F for method evaluation microbiology.