Bifidobacterium bifidum is a bacterial species exclusively found in the human intestinal tract. This species is becoming increasingly popular as a probiotic organism added to lyophilized products. In this study, porcine mucin was used as the sole carbon source for the selective enumeration of B. bifidum in probiotic food additives. Thirty-six bifidobacterial strains were cultivated in broth with mucin. Only 13 strains of B. bifidum utilized the mucin to produce acids. B. bifidum was selectively enumerated in eight probiotic food supplements using agar (MM agar) containing mupirocin (100 mg/L) and mucin (20 g/L) as the sole carbon source. MM agar was fully selective if the B. bifidum species was presented together with Bifidobacterium animalis subsp. lactis, Bifidobacterium breve, and Bifidobacterium longum subsp. longum species and with lactic acid bacteria (lactobacilli, streptococci). Isolated strains of B. bifidum were identified using biochemical, PCR, MALDI-TOF procedures and 16S rRNA gene sequencing. The novel selective medium was also suitable for the isolation of B. bifidum strains from human fecal samples.

Department of Agri food and Environmental Systems Management University of Catania Via S Sofia 100 95123 Catania Italy

Department of Microbiology Nutrition and Dietetics Faculty of Agrobiology Food and Natural Resources Czech University of Life Sciences Kamycka 129 Prague 6 165 21 Czech Republic

Institute of Animal Physiology and Genetics v v i Academy of Sciences of the Czech Republic Vídenská 1083 Prague 4 142 20 Czech Republic

Institute of Animal Physiology Slovak Academy of Sciences Soltesovej 4 6 040 01 Kosice Slovakia

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