Direct loop-mediated isothermal amplification (LAMP) assay for rapid on-site detection of Bifidobacterium longum subspecies longum , infantis, and suis in probiotic products

As interest in probiotics increases, the need for accurate description of probiotic compositions present in commercial products is also increasing. Since Bifidobacterium longum used as probiotics is labeled at species or subspecies levels, a detection method for distinguishing B. longum subsp. longum, infantis, and suis is needed. Thus, we designed three LAMP primer sets for B. longum subspecies. Each primer set was specific for the target subspecies. The detection level was 0.2 pg for each target DNA (about 10(2) CFU/mL). To apply these LAMP assays to on-site detection, a direct DNA extraction method was optimized and combined with LAMP assay. Finally, direct LAMP assays were used to monitor the presence of B. longum subspecies in 16 probiotic products. They could specifically and sensitively detect target subspecies within approximately 45 min. These rapid on-site detection methods are useful for identifying B. longum subspecies in probiotic products.

Automated summary

As interest in probiotics grows, accurate description of probiotic compositions in commercial products is increasingly needed. Three specific LAMP primer sets for distinguishing B. longum subspecies were designed and optimized for on-site detection, successfully detecting target subspecies in probiotic products within approximately 45 minutes. These rapid detection methods are useful for identifying B. longum subspecies in probiotic products.