The effect of using bifidobacteria spp. in the manufacturing of yoghurt and low salt soft cheese on the growth of Escherichia coli and Staphylococcus aureus was studied. When B. bifidum or B. longum was inoculated with these bacteria, the numbers of their population gradually decreased and disappeared in yoghurt on the 15^th and 10^th day of storage period at 4ºC for E. coli, respectively. On the other hand, Staph aureus population was disappeared on the 10^th and 7^th day of storage period. Addition of B. bifidum or B. longum inhibited the growth of E. coli and Staph aureus in low salt soft cheese during storage at 4ºC after 7 and 5 days of storage in cheese inoculated with B. longum, respectively. While both organisms couldn't be detected on the 7^th day of storage in cheese inoculated with B. bifidum. The results of the current study indicated application of bifidobacteria spp. as biopreservative cultures in dairy products.