Studies on the Antimicrobial Activity of Some Probiotic Bacteria and their Usage as a Bio-preservative.
Ebtehag Abdelfattah Elsebaiey Saker;
Abstract
Three lactic acid bacterial strains (Bifidobacterium bifidum, Lactobacillus acidophilus La-5 and Lactobacillus casei-01) were characterized to select the best candidate one. Lactobacillus acidophilus La-5 appeared to be the best probiotic one achieving most criteria tested including antimicrobial activity, acid and bile tolerance, lysozyme resistance, phenol tolerance, antibiotic resistance, gelatinase and haemolytic activity, auto-aggregation, co-aggregation, cell surface hydrophobicity and biofilm formation.
To produce economically low cost media comparable with the synthetic Mann Rogosa Sharpe (MRS) media, several attempts were done to exploit the best agro-industrial waste materials namely sugar cane molasses and cheese whey as cheaper available raw substrates. This media was used for growing L. acidophilus La-5 to produce antimicrobial metabolites and biomass. The optimized cheese whey-based medium was found to be the useful and economical one for the production of L. acidophilus La-5 biomass. Production of organic acids (lactic acid, citric acid and propionic acid) by L. acidophilus La-5 in both optimized cheese whey (CW) and MRS media was determined. Formic acid was not produced in MRS broth but it was produced in CW.
The effect of cell free culture supernatant (metabolites) of L. acidophilus La-5 grown in MRS and CW based medium on the morphology of S. typhimurium cells was assayed by transmission electron microscope showing an alteration in morphology.
Microencapsulated cells of L. acidophilus La-5 were assayed for the ability to survive at low pH and high bile-salt concentration compared with non-capsulated cells. It was found that survival of microencapsulated L. acidophilus La-5 was improved by almost 4 times compared with the free cells reveal.
Yoghurt was manufactured, as a bio- product, using L. bulgaricus and Str. thermophilus mainly as the original starter cultures. Free and microencapsulated L. acidophilus La-5 with and without sorbitol (as a prebiotic agent) were used as bio-preservative additives. Yoghurt with microencapsulated and sorbitol addition, was found to be the best treatment for stability, viability of microencapsulated L. acidophilus La-5 during fifteen days cold storage, sensory acceptance and complete reduction of S. typhimurium and E. coli O157.
To produce economically low cost media comparable with the synthetic Mann Rogosa Sharpe (MRS) media, several attempts were done to exploit the best agro-industrial waste materials namely sugar cane molasses and cheese whey as cheaper available raw substrates. This media was used for growing L. acidophilus La-5 to produce antimicrobial metabolites and biomass. The optimized cheese whey-based medium was found to be the useful and economical one for the production of L. acidophilus La-5 biomass. Production of organic acids (lactic acid, citric acid and propionic acid) by L. acidophilus La-5 in both optimized cheese whey (CW) and MRS media was determined. Formic acid was not produced in MRS broth but it was produced in CW.
The effect of cell free culture supernatant (metabolites) of L. acidophilus La-5 grown in MRS and CW based medium on the morphology of S. typhimurium cells was assayed by transmission electron microscope showing an alteration in morphology.
Microencapsulated cells of L. acidophilus La-5 were assayed for the ability to survive at low pH and high bile-salt concentration compared with non-capsulated cells. It was found that survival of microencapsulated L. acidophilus La-5 was improved by almost 4 times compared with the free cells reveal.
Yoghurt was manufactured, as a bio- product, using L. bulgaricus and Str. thermophilus mainly as the original starter cultures. Free and microencapsulated L. acidophilus La-5 with and without sorbitol (as a prebiotic agent) were used as bio-preservative additives. Yoghurt with microencapsulated and sorbitol addition, was found to be the best treatment for stability, viability of microencapsulated L. acidophilus La-5 during fifteen days cold storage, sensory acceptance and complete reduction of S. typhimurium and E. coli O157.
Other data
| Title | Studies on the Antimicrobial Activity of Some Probiotic Bacteria and their Usage as a Bio-preservative. | Other Titles | " دراسة علي نشاط التضاد الميكروبي لبعض سلالات البروبيوتيك وإستخدامها كمواد حيوية حافظة." | Authors | Ebtehag Abdelfattah Elsebaiey Saker | Issue Date | 2017 |
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