scholarly journals Antibacterial Activity of Lactic Acid Bacteria Isolated from Fermented Ethiopian Traditional Dairy Products against Food Spoilage and Pathogenic Bacterial Strains

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Abayeneh Girma ◽  
Aleka Aemiro
Keyword(s):  
Antibacterial Activity ◽  
Dairy Products ◽  
Pathogenic Bacteria ◽  
Antibacterial Activities ◽  
Food Spoilage ◽  
Bacterial Strains ◽  
Secondary Screening ◽  
Traditional Dairy Products ◽  
Fermented Dairy Products ◽  
Fermented Dairy

Fermented Ethiopian traditional dairy products containing LAB that show antibacterial activities against various food spoilage and pathogenic bacteria have been used for the preservation of fermented dairy products for a long time. However, there are no comprehensive scientific reports on the antibacterial activity of LAB isolated from various fermented dairy products in Pawe Woreda. The objective of the study was to evaluate the antibacterial activity of LAB isolated from traditionally fermented Ethiopian dairy products against spoilage and pathogenic bacteria. Thirty-five samples of fermented dairy products were collected from three cattle-farming areas of Pawe Woreda. A total of 97 LAB were isolated and screened primarily using the perpendicular streak plate method against 3 Gram-positive and 3 Gram-negative bacterial strains. Out of the 97 strains, 10 were active against at least two of the tested bacteria, of which 7 strains were selected for secondary screening by their broad-spectrum antibacterial activities. The seven in vitro antibacterial activities of the extract ranged from 5 to 16 mm in diameter during the secondary screening. In this study, Z2, Z4, and N2 strains exhibited the highest inhibition zone with broad-spectrum activity against all tested bacteria. The MIC and MBC values range from 0.10 to 0.30 µg/µL and 0.20 to 0.50 µg/µL, respectively. Following morphological, physiological, biochemical, and molecular characteristics, seven potent strains were identified as Lactobacillus acidophilus, Lactobacillus paracasei, Lactobacillus plantarum, Lactobacillus rhamnosus, Leuconostoc mesenteroides, Streptococcus thermophilus, and Lactococcus lactis. According to the findings of this study, Ethiopian fermented dairy products were the most potent source of bioactive compounds with potential effects against food spoilage and pathogenic bacterial strains.

Probiotics Down-Regulate flaA σ28 Promoter in Campylobacter jejuni

2005 ◽  
Vol 68 (11) ◽  
pp. 2295-2300 ◽  
Author(s):  
WU DING ◽  
HAIFENG WANG ◽  
MANSEL W. GRIFFITHS
Keyword(s):  
Campylobacter Jejuni ◽  
Dairy Products ◽  
Promoter Activity ◽  
Streptococcus Thermophilus ◽  
Scientific Data ◽  
Bacterial Strains ◽  
Positive Effects ◽  
Probiotic Strains ◽  
Fermented Dairy Products ◽  
Fermented Dairy

Lactobacilli and bifidobacteria are important members of the gastrointestinal microflora of humans and animals and are thought to have positive effects on human health. Therefore, there is an increasing interest in using these microorganisms as probiotics to be incorporated into either fermented dairy products or tablets. However, convincing scientific data that support claims of their health benefits are scarce. The effect of cell-free extracts of milk fermented by 10 probiotic bacteria (five Bifidobacterium strains and five Lactobacillus strains) on the expression of the flaA gene of Campylobacter jejuni was assessed using a fusion between the flaA σ28 promoter and a promoterless luxCDABE cassette carried on the plasmid pRYluxCDABE, which resulted in strains with quantifiable luminescence linked to flaA σ28 promoter activity. Cell-free extracts of milk fermented by all of the tested probiotic strains inhibited the growth of the C. jejuni and down-regulated flaA σ28 promoter activity. Two nonprobiotic lactic acid bacterial strains, Lactococcus lactis and Streptococcus thermophilus, were less inhibitory.

scholarly journals Extraction and Isolation of Compound from Roots of Kniphofia pumila, and Its Antibacterial Activities in Combination with Zinc Chloride

2020 ◽  
Vol 17 (7) ◽  
pp. 631-638
Author(s):  
Dele ABDISSA ◽  
Gezahegn FAYE ◽  
Melkamu FAYERA ◽  
Shiferaw DEMISSIE
Keyword(s):  
Antibacterial Activity ◽  
Crude Extract ◽  
Pathogenic Bacteria ◽  
Antibacterial Activities ◽  
Diffusion Method ◽  
Spectroscopic Techniques ◽  
Bacterial Strains ◽  
Pure Compound ◽  
Standard Drug ◽  
Isolated Compound

Kniphofia pumila has been traditionally used for the treatment of different diseases in Oromiya regional state, western part of Ethiopia. Thus, the main objective of this study was to extract bioactive natural products from the roots of K. pumila and perform in vitro antibacterial activity tests against selected pathogens. Extraction of compound from the roots of K. pumila was carried out by maceration method at room temperature and its antibacterial activity was done using agar disc diffusion method. The crude extracts alone and along with ZnCl2 were tested against pathogenic bacteria Escherichia coli (ATCC 25722), Klebsiella pneumoniae subsp. pneumoniae (DSM 19613), Staphylococcus aureus (ATCC 25925) and Salmonella Typhimurium (ATCC 13311). Following its promising activity, the acetone crude extract that have shown better antibacterial activity was subjected to column chromatography for isolation of pure compound. Hence, one pure compound (GZ-1) was obtained from acetone crude extract. Meanwhile, the antibacterial activities of the isolated compound alone and in combination with ZnCl2 were also performed against all aforementioned bacterial strains. Then, isolated compound was characterized by using NMR spectroscopic techniques such as 1H-NMR, 13C-NMR and, 2D NMR, so as to establish its structure as 3’-acetyl-2’,6’-dihydroxy-4-methoxyphenyl-1,8-dihydroxy-3-methylanthraquinone, trivial name knipholone. Finally, GZ-1 was isolated from the roots of K. pumila and it was noted that the antibacterial activities of ZnCl2 in combination with crude extract as well as with isolated compound against E. coli (ATCC 25722), S. aureus (ATCC 25925) and S. Typhimurium (ATCC 13311) bacterial strains showed remarkable results which were greater than the antibacterial activity of the positive standard drug (gentamycin). To sum up, from the chromatographic isolation of roots acetone extract of K. pumila one pure compound (knipholone) was obtained. Its antibacterial activity was also evaluated in combination with ZnCl2 salt and alone.

Antioxidant and Antibacterial Activities of Artemisia herba-alba Asso Essential Oil from Middle Atlas, Morocco

2018 ◽  
Vol 16 (S1) ◽  
pp. S48-S54
Author(s):  
Y. Ez zoubi ◽  
S. Lairini ◽  
A. Farah ◽  
K. Taghzouti ◽  
A. El Ouali Lalami
Keyword(s):  
Antibacterial Activity ◽  
Essential Oil ◽  
Foodborne Pathogens ◽  
Food Systems ◽  
Antibacterial Activities ◽  
Culture Collection ◽  
Bornyl Acetate ◽  
Bacterial Strains ◽  
Disk Diffusion Assay ◽  
Different Strains

The purpose of this study was to determine the chemical composition and to evaluate the antioxidant and antibacterial effects of the Moroccan Artemisia herba-alba Asso essential oil against foodborne pathogens. The essential oil of Artemisia herba-alba was analyzed by gas chromatography coupled with mass spectroscopy. The antibacterial activity was assessed against three bacterial strains isolated from foodstuff and three bacterial strains referenced by the ATCC (American Type Culture Collection) using the disk diffusion assay and the macrodilution method. The antioxidant activity was evaluated using the DPPH (2, 2-diphenyl-1- picrylhydrazyl) method. The fourteen compounds of the Artemisia herba-alba essential oil were identified; the main components were identified as β-thujone, chrysanthenone, α-terpineol, α-thujone, α-pinene, and bornyl acetate. The results of the antibacterial activity obtained showed a sensitivity of the different strains to Artemisia herba-alba essential oil with an inhibition diameter of 8.50 to 17.00 mm. Concerning the MICs (minimum inhibitory concentrations), the essential oil exhibited much higher antibacterial activity with MIC values of 2.5 μl/ml against Bacillus subtilis ATCC and Lactobacillus sp. The essential oil was found to be active by inhibiting free radicals with an IC50 (concentration of an inhibitor where the response is reduced by half) value of 2.9 μg/ml. These results indicate the possible use of the essential oil on food systems as an effective inhibitor of foodborne pathogens, as a natural antioxidant, and for potential pharmaceutical applications. However, further research is needed in order to determine the toxicity, antibacterial, and antioxidant effects in edible products.

scholarly journals Effect of probiotic fermented dairy products on incidence of respiratory tract infections: a systematic review and meta-analysis of randomized clinical trials

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Kamil Rashidi ◽  
Bahman Razi ◽  
Mina Darand ◽  
Azadeh Dehghani ◽  
Parisa Janmohammadi ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Protective Effect ◽  
Dairy Products ◽  
Respiratory Tract Infections ◽  
Randomized Clinical Trials ◽  
Meta Analysis ◽  
Total Sample ◽  
Fermented Dairy Products ◽  
Tract Infections ◽  
Fermented Dairy

Abstract Background Previous studies have suggested that the consumption of probiotic fermented dairy products (PFDP) may have a protective effect on respiratory tract infections (RTIs). However, the results of studies are inconclusive. We aimed to systematically investigate the effect of PFDP on RTIs by performing a meta-analysis of randomized controlled trials (RCTs). Methods PubMed and Scopus databases were systematically searched up to October 2020 to identify eligible RCTs. Meta-analysis outcomes were risk of incidence of upper (URTIs ) and lower (LRTIs ) respiratory tract infections. A random-effects model was used to pool the relative risks (RR) and corresponding 95 % confidence intervals (CI) for outcomes following conception of PFDP. Results A total of 22 RCTs, with a total sample size of 10,190 participants, were included in this meta-analysis. Compared with placebo, consumption of PFDP had a significant protective effect against RTIs in the overall analysis (RR = 0.81, 95 %CI: 0.74 to 0.89) and in children (RR = 0.82, 95 %CI: 0.73 to 0.93), adults (RR = 0.81, 95 %CI: 0.66 to 1.00), and elderly population (RR = 0.78, 95 %CI: 0.61 to 0.98). The significant decreased risk of RTIs was also observed for URTIs (RR = 0.83, 95 %CI: 0.73 to 0.93), while, this effect was marginal for LRTIs (RR = 0.78, 95 %CI: 0.60 to 1.01, P = 0.06). The disease-specific analysis showed that PFDP have a protective effect on pneumonia (RR = 0.76, 95 %CI: 0.61 to 0.95) and common cold (RR = 0.68, 95 %CI: 0.49 to 0.96). Conclusions Consumption of PFDP is a potential dietary approach for the prevention of RTIs.

Identification of L. casei and L. rhamnosus in the dairy products using Real-Time PCR assay

2015 ◽  
Vol 4 (5) ◽  
pp. 222-225
Author(s):  
K. G. Li ◽  
G. P. Pogossian ◽  
A. K. Moldagulova ◽  
E. E. Bekenova ◽  
A. Abdikadirova ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Dairy Products ◽  
Production Control ◽  
High Efficiency ◽  
High Specificity ◽  
Industrial Test ◽  
Fermented Dairy Products ◽  
Species Specific ◽  
Fermented Dairy

  Lactobacilli are essential and important biological objects used in food pro-duction and medicine. One of the sufficient problems is fast, reliable and highly specific identification of lactobacilli in the scientific research and cur-rent production control. We represent two species-specific real-time PCR in the present study to discriminate L. rhamnosus and L. casei basing on the unique peptidoglycan-hydrolase genes p40 and p75 respectively. PCR pri-mers and probes were designed to provide high specificity discrimination via high temperature of PCR annealing stage. High efficiency of the reactions is provided by the size of amplified DNA fragments minimization. Reliable re-producibility of the target sequences amplification and fluorescence detec-tion provide a basis for the future creation of industrial test-systems for op-erational control in the production of fermented dairy products.

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