TITLE:
Dominant Lactic Acid Bacteria and Their Antimicrobial Profile from Three Fermented Milk Products from Northern Namibia
AUTHORS:
L. N. Heita, A. Cheikhyoussef
KEYWORDS:
Namibia, Traditional Fermented Milk, Lactic Acid Bacteria, Omashikwa, Mabisi, Mashini ghamushikwa
JOURNAL NAME:
Journal of Biosciences and Medicines,
Vol.2 No.9,
November
25,
2014
ABSTRACT: The present study focused on the isolation,
identification and antimicrobial profile of the dominant lactic acid bacteria from
three traditional fermented milk products namely: Omashikwa, Mabisi and Mashini
Ghamushikwa from the north-central and north-eastern parts of Namibia. The microbiological
and antimicrobial activities of these products fluctuate from one region to another
depending on the local indigenous microflora. Omashikwa and Mashini Ghamushikwa
fermentation processes involves the addition of Boscia albitrunca root (Omunkuzi)
and butter churning. The root contributes to the flavor of the product, increasing
the milk fermentation rate and churning. Mabisi is produced by letting the milk
to ferment naturally until the water is separated from the whey. The water is then
decanted, and the whey is shaken until it is smooth without removal of fat. A total
of 180 isolates of Lactic acid bacteria (LAB) were obtained and identified based
on their phenotypical characterization. Cell free supernatants (CFS) of the 180
LAB isolates were evaluated for antimicrobial activities against selected food borne
pathogens; Escherichia coli ATCC 25,922, Staphylococcus aureus ATCC 25,923, Bacillus
cereus ATTC 10,876, Candida famata and Geotrichum klebahnii using the well diffusion
assay. Twenty LAB isolates having the highest inhibitory effects were selected for
biochemical identification using API 50 kit and these were identified as being;
Lactobacillus plantarum (53%), Lactobacillus rhamnosus (29%), Pediococcus pentosaceus
(6%), Lactobacillus paracasei ssp. paracasei (6%) and Lactococcus lactic ssp. lactis
(6%). Pediococcus pentosaceus showed the highest inhibitory effect on all the indicator
strains. This study provides an insight into LAB diversity of unstudied Namibian
fermented milk products and reports a potential production of antimicrobial compounds
which is significant in the standardization of protective starter cultures which
can be used to control fermentation process and shelf life extension of dairy products
in Namibia.