In Vitro Evaluation of the Probiotic Potential of Lactic Acid Bacterial Strains Retrieved from Raw and Traditionally Fermented Cow Milk

Bile salt; Dairy products; Gastric acid; Lactic acid bacterial; Probiotic potential

Authors

  • Mulatu Workie
    mulatudst6@gmail.com
    Holetta National Agricultural Biotechnology Research Centre, Ethiopian Institute of Agricultural Research (EIAR), Ethiopia
  • Betemariam Kebede Holetta National Agricultural Biotechnology Research Centre, Ethiopian Institute of Agricultural Research (EIAR), Ethiopia
  • Tefera Tadesse Holetta National Agricultural Biotechnology Research Centre, Ethiopian Institute of Agricultural Research (EIAR), Ethiopia
  • Daniel Yimer Holetta National Agricultural Biotechnology Research Centre, Ethiopian Institute of Agricultural Research (EIAR), Ethiopia
  • Tirsit Tibebu Holetta National Agricultural Biotechnology Research Centre, Ethiopian Institute of Agricultural Research (EIAR), Ethiopia
  • Sewunet Abera Holetta National Agricultural Biotechnology Research Centre, Ethiopian Institute of Agricultural Research (EIAR), Ethiopia
  • Adaba Tilahun Holetta National Agricultural Biotechnology Research Centre, Ethiopian Institute of Agricultural Research (EIAR), Ethiopia
  • Melaku Alemu Ethiopian Agricultural Research Council Secretariat, Ethiopia
  • Tadessa Daba Holetta National Agricultural Biotechnology Research Centre, Ethiopian Institute of Agricultural Research (EIAR), Ethiopia
  • Adane Eshetu Holetta National Agricultural Biotechnology Research Centre, Ethiopian Institute of Agricultural Research (EIAR), Ethiopia
  • Asab Alemneh Holetta National Agricultural Biotechnology Research Centre, Ethiopian Institute of Agricultural Research (EIAR), Ethiopia
  • Birhanu Babiye Holetta National Agricultural Biotechnology Research Centre, Ethiopian Institute of Agricultural Research (EIAR), Ethiopia
  • Gudeta Dida Holetta National Agricultural Biotechnology Research Centre, Ethiopian Institute of Agricultural Research (EIAR), Ethiopia
  • Tariku Abena Holetta National Agricultural Biotechnology Research Centre, Ethiopian Institute of Agricultural Research (EIAR), Ethiopia
June 1, 2022

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Background: Probiotics are live bacteria found mostly in milk and milk products that have been
shown to improve intestinal microflora composition, treat lactose intolerance, prevent cancer, allergies,
hepatic illness, and lower cholesterol. Ethiopians consume a lot of dairy and dairy products. However,
little is known about the starter and probiotic properties of the lactic acid bacteria consumed with these
items in the country.
Objective: The objective of this research was to identify and evaluate the probiotic functioning of
lactic acid bacteria from raw and traditional fermented cow milk.
Materials and Methods: Lactic acid bacteria were isolated from raw milk and yoghurt samples
collected from Ethiopia (Holetta, Adama and Bishoftu). Three hundred and fifty colonies exhibiting
the characteristic features of lactic acid bacteria were used for gastric and bile salt tolerance tests.
Results: From among the 27 isolates, 10 (37%) showed a significant tolerance to the various ranges
of gastric pH and bile salt concentrations (P ≤ 0.05). The highest gastric acid tolerance was observed
for the isolate AD6 (OD = 1.352 ± 0.063) at the gastric pH of 4.0 at 24th hours of incubation followed
for the isolate NZ26 (OD = 0.870 ± 0.058) at the same gastric pH and incubation hour. Isolate G25
(OD = 0.733 ± 0.103) was able to tolerate 2% (w/v) of bile salt at 2 h of incubation time. Four isolates
DZ3 (OD = 0.578±0.103), G37 (OD = 0.657 ± 0.046), AD22 (OD = 0.683 ± 0.072) and NZ3 (OD
= 0.694 ± 0.070) showed a significance tolerance at 1% (w/v) of bile salt concentration at the 24th
hours of incubation.
Conclusion: The findings revealed that naturally occurring lactic acid bacteria isolated from dairy
products have the potential for probiotic applications in the dairy industry in the country.This could
pave the way for exploiting the isolates at industrial level and could transform traditional dairy
processing with probiotic function in Ethiopia.