Objective To compare different preparation methods for quantitative real-time PCR (qPCR) detection of Bifidobacteria. Methods Standard strains of Bifidobacteria were prepared with concentration gradients using strain DNA, PCR product amplification and purification, and plasmid DNA methods. The concentrations of Bifidobacteria were determined with ultraviolet spectrophotometer and real-time quantitative PCR. Results Greater than 0.99 R 2 in values of standard curves were achieved by all three preparation methods. The plasmid DNA method obtained a higher level of concentration and purity of Bifidobacteria than the other two methods （ PBifidobacteria.
