Diversity, phylogenetic relationship and antibacterial potential of Bifidobacterium species isolated from raw milk production chain in Abidjan (Côte d'Ivoire)

in African Journal of Microbiology Research [=AJMR] (2011), 5(21), 3394-3403

The local dairy commodity, from farm to retail point, is informal and often escapes safety surveillance and results in high contamination of local milk by pathogens. The objective of this study was to ... [more ▼]

The local dairy commodity, from farm to retail point, is informal and often escapes safety surveillance and results in high contamination of local milk by pathogens. The objective of this study was to determine the biodiversity of Bifidobacterium species in the informal dairy production chain in Abidjan and evaluate their potential antibacterial activity against pathogens. Bifidobacterium species were identified after sequencing of hsp60 genes. Results showed that Bifidobacterium were present in 9% of samples. Milkers' hands (14%) and cows’s udders (14%) were the most contaminated with Bifidobacterium. These isolates belong to five different species. Most Bifidobacterium isolated are Bifidobacterium minimum (53%) and Bifidobacterium pseudolongum subsp. Globosum (24.4%). The other strains are composed of one strain of Bifidobacterium thermophilum, Bifidobacterium thermacidophilum subsp. suis and Bifidobacterium magnum. The isolated Bifidobacterium species have antibacterial activities that are not related to bacteriocins production, but to organic acids production (65%), which exert in vitro inhibitory action against Listeria monocytogenes, Salmonella hadar and Salmonella typhimurium, Staphylococcus aureus, Escherichia coli O27 and Escherichia coli O157H7. However, ensuring milk safety along the local milk production chain requires implementation of good hygiene practices together with adapted technology, such as fermentation. [less ▲]

Isolation and characterisation of new spore-forming lactic acid bacteria with prospects of use in food fermentations and probiotic preparations

in African Journal of Microbiology Research [=AJMR] (2010), 4(11), 1016-1025

In Vitro Detection And Characterization Of Bacteriocin-Like Inhibitory Activity Of Lactic Acid Bacteria (Lab) Isolated From Senegalese Local Food Products

in African Journal of Microbiology Research [=AJMR] (2008), 2(8),

The prevalence of lactic acid bacteria (LAB) in Senegalese local food products was determined to be 109 CFU/g in millet flour and milk products, and 103 CFU/g in seafood products. These food products are ... [more ▼]

The prevalence of lactic acid bacteria (LAB) in Senegalese local food products was determined to be 109 CFU/g in millet flour and milk products, and 103 CFU/g in seafood products. These food products are generally preserved by spontaneous fermentation (without addition of starters). Of 220 lactic acid bacteria strains randomly selected from such products, 12 isolates capable of producing bacteriocin-like substances (bac+) were detected. Based on the use of API 50 CH test kits and 16S rDNA sequencing, 11 isolates were characterized as Lactococcus lactis subsp. lactis strains and one as an Enterococcus faecium strain. Nisin- and enterocin B-encoding genes were respectively identified in the bac+ lactococcal strains and the E. faecium strain. Since the bac+ Lc. lactis strains were isolated from different products, it suggests a high potential of growth by these strains in variable ecological environments. Expression of the nisin gene was indicated for one of the lactococcal strains, designated Lc. lactis subsp. lactis CWBI-B1410, which showed the highest in vitro antibacterial activity. An antibacterial preparation prepared from the CWBI-B1410 strain showed many similarities with nisin with regards to its inhibitory effects, heat resistance, protease sensitivity profile, as well as retention time of the antibacterial substances on a C18 column. These results suggest that a nisin-like substance is produced by the CWBI-B1410 strain. This strain has been selected for application as an additional barrier to supplementation with sodium chloride as a means to improve the bacterial quality of fish commodities in Senegal. [less ▲]