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