| dc.description.abstract | Bifidobacterium is a genus of Gram- positive, non- motile, often branched anaerobic bacteria inhabiting the human gastrointestinal tract and vagina. Bifidobacteria exert a range of beneficial health effects and are considere d as important probiotic and used in the food industry to relieve and treat many intestinal disorders. The Bifidobacterium populations in commercial dairy and functional food products should be over 106 CFU/g at the time of consumption.
Spread-plate count methods were use d for isolation and enumeration of
Bifidobateria in some selected dairy products from the local market . De Man Rogosa
Sharpe (MRS) medium supplemented with L-cystein and an appropriate
concentration (100mg/L) of mupiroc in showed to be suitable for screening
Bifidobacteria, while supplementation with lithium chloride and propionate did not. Further, Bifidobacteria were differentiated and identified by the test of Gram-staining and analysis of morphological characteristics.
The catalase test was performed, which confirmed the presence of Bifodobacteria but did not differentiate Bifidobateria from others, since all samples showed negative results, even though they we re from different genus by morphologic al analysis.
However, Thin Layer Chromatography (TLC) analysis showed to be a simple, rapid, and economical method for presumptive identification of Bifidobacterium at the genus level. The results of these processes were confirmed by sequencing 16s RNA of mic roorganism and using global alignment with gene bank.
The products chosen for this study were the dairy and pharmaceutical
products in Vietnam market including drinking milk, powder milk, and supple mental
bacteria powder. One of the three products tested showed to contain Bifodobacteria,
as claimed on its label, while two others did not. Further, the level of Bifidobateria in
those products may be far be low the recommended one of 1.0x106 CFU/g.
The results from this study raised the need for stronger measures of quality
control for probiotic products available in the market. Also, the TLC method was
recommended for rapid and c heap method for detection of Bifidobacteria, followed
the screening by mMRS medium supplemented with L-cystein and mupirocin. | en_US |
