M Khomeiri - PhD. Student of Food Science and Technology
S.A Mortazavi - Professor
H.B Ghoddusi - Associate Professor, Food Science and Technology Department, Agriculturl School, Mashhad University of Medical Sciences, Mashhad, Iran
A Khamessan - Member of Animal Science Research Institute, Karaj, Iran
D Ahmad - Faculty Member of INRS, Canada
F Shahidi - Associate Professor, Food Science and Technology Department, Agriculturl School, Mashhad University of Medical Sciences, Mashhad, Iran

For the first time in Iran ۴۰ strains of Bifidobacterium were isolated from feces of Iranian subjects. By using phenotypic tests, ۱۸ isolates were identified as Bifidobacterium longum, ۱۰ as Bifidobacterium bifidum and one as Bifidobacterium catenolatum. In order to validate these results and also to identify other isolates that had not been identified by phenotypic tests, two methods of PCR with genus-specific primers of Bif۱۶۴f and Bif۶۰۱r and ۱۶SrRNA gene sequence analysis were applied. Results of PCR confirmed the obtained phenotypic identifications. Moreover by this method the ۸ remaining strains were identified as Bifidobacterium species. Using sequencing ۱۶SrRNA gene, ۵ B. longum strains were identified that had different fermentation pattern from B. longum. Some new ribose negative Bifidobacterium longum strains were also identified. The obtained results present new strains of Bifidobacterium longum.

Bifidobacterium, ۱۶S rRNA, PCR, Iranian strains, Bif ۱۶۴f, Bif ۶۰۱r, Identification