University of Khartoum

Inhibitory Effect of Lactic Acid Bacteria on Staphylococcus Arueus Growth at Some Specific Factors

Inhibitory Effect of Lactic Acid Bacteria on Staphylococcus Arueus Growth at Some Specific Factors

Show full item record

Title: Inhibitory Effect of Lactic Acid Bacteria on Staphylococcus Arueus Growth at Some Specific Factors
Author: Shareef, Rayan Abdallateef Mohmmed
Abstract: Background: Food contamination by Staphylococcus aureus is considered a major problem for the health of the consumer. The use of bacterial interactions is a new way to limit the growth of disease-causing germs. Lactic acid bacteria produce bacteriocin, a protein linked to a complex which inhibits the growth of other related bacterial species. This study aimed to investigate the inhibitory effectof lactic acid bacteria on the growth of Staphylococcus aureus in the presence of some specific factors. Methdology: This was anexperimental study.Pure culture of lactic acid bacteria isolated from fermented milk was incubated in twelve test tubes in Man –Rogosa –Shape broth at a temperature of 37 ͦCfor 48 hours at neutral pH. Pure culture of Staphylococcus aureus ATCC 25923 incubated at 37 ͦC for 24 hours. The impact of pH, temperature and salt concentrations on the lactic acid bacteria inhibition on Staphylococcus aureusgrowth was assessed: Staphylococcusaureusspreaded on the surfaces of four nutrient agar platesand 2-3 wells were punched then filled with isolated lactic acid bacteria and each plate incubated at different temperatures: 20ͦC, 37 ͦC, 45 ͦC and at 62ͦCfor 24 hrs. To determine the impact of genitive concentrations ofNaCl(3%, 6%, 12% and 18%), Staphylococcusaureusspreaded on the nutrient agar platessurfacesand 2-3 wells were punched then filled with isolated lactic acid bacteria and incubated at 37ͦC for 24 hrs. AdjustedpH at 2, 3.5, 5 and 9,Staphylococcusaureusspreaded on nutrient agar platessurfaces and 2-3 wells were punched then filled with isolated lactic acid bacteria and plates incubated 37ͦC for 24 hrs. Results: The highest inhibition zone of lactic acid bacteria onStaphylococcusaureus growthwas 17 millimeter at 20ͦC and the lowest inhibition zone was 12 millimeter at NaCl 3% , while no inhibition zonemeasuredat NaCl 6% ,18% andno inhibition zonemeasuredat pH5 and 9. Conclusion: It's evident that,lactic acid bacteria has strong inhibitory effect of on the growth of Staphylococcus aureus in the presence of some specific factors (values of pH, temperatures and concentrations of NaCl).Therefore, the current study suggests application of this inhibitory effect in fermented foods in specific amounts.
Description: 48page
URI: http://khartoumspace.uofk.edu/123456789/25920


Files in this item

Files Size Format View

This item appears in the following Collection(s)

Show full item record

Share

Search DSpace


Browse

My Account