scholarly journals Virulence factors, serogroups and antimicrobial resistance properties of Escherichia coli strains in fermented dairy products

2014 ◽  
Vol 7 (1) ◽  
Author(s):  
Farhad Safarpoor Dehkordi ◽  
Farshad Yazdani ◽  
Jalal Mozafari ◽  
Yousef Valizadeh
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Virulence Factors ◽  
Dairy Products ◽  
Fermented Dairy Products ◽  
Fermented Dairy

Persistence of Escherichia coli O157:H7 in Dairy Fermentation Systems

1998 ◽  
Vol 61 (12) ◽  
pp. 1602-1608 ◽  
Author(s):  
SEAN S. DINEEN ◽  
KAZUE TAKEUCHI ◽  
JANE E. SOUDAH ◽  
KATHRYN J. BOOR
Keyword(s):  
Escherichia Coli ◽  
Lactococcus Lactis ◽  
Dairy Products ◽  
Starter Cultures ◽  
Escherichia Coli O157 ◽  
Potential Health ◽  
E Coli ◽  
Lactococcus Lactis Subsp ◽  
Fermented Dairy Products ◽  
Fermented Dairy

We examined (i) the persistence of Escherichia coli O157:H7 as a postpasteurization contaminant in fermented dairy products; (ii) the ability of E. coli O157:H7 strains with and without the general stress regulatory protein, RpoS, to compete with commercial starter cultures in fermentation systems; and (iii) the survival of E. coli O157:H7 in the yogurt production process. In commercial products inoculated with 103 CFU/ml, E. coli O157:H7 was recovered for up to 12 days in yogurt (pH 4.0), 28 days in sour cream (pH 4.3), and at levels >102 CFU/ml at 35 days in buttermilk (pH 4.1). For the starter culture competition trials, the relative inhibition of E. coli O157:H7 in the experimental fermentation systems was, in decreasing order, thermophilic culture mixture, Lactobacillus delbrueckii subsp. bulgaricus R110 alone, Lactococcus lactis subsp. lactis D280 alone, Lactococcus lactis subsp. cremoris D62 alone, and Streptococcus thermophilus C90 alone showing the least inhibition. Recovery of the rpoS mutant was lower than recovery of its wild-type parent by 72 h or earlier in the presence of individual starter cultures. No E. coli O157:H7 were recovered after the curd formation step in yogurt manufactured with milk inoculated with 105 CFU/ml. Our results show that (i) postprocessing entry of E. coli O157:H7 into fermented dairy products represents a potential health hazard; (ii) commercial starter cultures differ in their ability to reduce E. coli O157:H7 CFU numbers in fermentation systems; and (iii) the RpoS protein appears to most effectively contribute to bacterial survival in the presence of conditions that are moderately lethal to the cell.

scholarly journals Characterization and transfer of antimicrobial resistance in lactic acid bacteria from fermented dairy products in China

2019 ◽  
Vol 13 (02) ◽  
pp. 137-148 ◽  
Author(s):  
Chao Yang ◽  
Tao Yu
Keyword(s):  
Lactic Acid ◽  
Antimicrobial Resistance ◽  
Lactic Acid Bacteria ◽  
Resistance Genes ◽  
Dairy Products ◽  
Active Role ◽  
Fermented Food ◽  
Antimicrobial Resistance Genes ◽  
Fermented Dairy Products ◽  
Fermented Dairy

Introduction: Lactic acid bacteria (LAB) are commonly found in foods and are also natural intestinal inhabitants in humans and most animals. However, information regarding antimicrobial resistance and the transfer of resistance genes of LAB from fermented dairy products in China is limited. Methodology: In this study, LAB isolates (n = 82) of Lactobacillus (n = 43) and Streptococcus thermophilus (n = 39) were isolated from 51 commercial fermented food samples in China. All isolates were subjected to pulsed-field gel electrophoresis (PFGE), antimicrobial susceptibility, detecting resistance genes, as well as investigating the transferability of resistance genes. Results: The 43 Lactobacillus isolates yielded 24 PFGE patterns and the 34 isolates of S. thermophilus generated 32 different PFGE patterns. Among the 43 Lactobacillus strains, the most commonly observed resistance was that to streptomycin (83.7%) and gentamycin (83.7%). Among the 39 S. thermophilus strains, the most frequently observed resistance was that to streptomycin (92.3%), gentamycin (87.2%), ciprofloxacin (79.5%), and chloramphenicol (71.8%), whereas the lowest level of resistance was that against erythromycin (7.7%). Antimicrobial resistance genes for erythromycin (emrB), gentamycin (aac(6')-aph(2")), streptomycin (ant(6)), sulfamethoxazole (sulI and sulII), tetracycline (tetM and tetS) were detected in the 18 resistance LAB strains. Conjugation experiments showed that tetM from L. delbrueckii subsp. bulgaricus R6 and tetS from L. plantarum R41 were successfully transferred to L. monocytogenes by filter mating. Conclusions: LAB strains could potentially act as reservoirs of resistance genes and play an active role in the transfer of resistance to humans via the food chain.

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.

Invited review: Potential antiobesity effect of fermented dairy products

2021 ◽  
Vol 104 (4) ◽  
pp. 3766-3778
Author(s):  
Carmen G. Manzanarez-Quín ◽  
Lilia M. Beltrán-Barrientos ◽  
Adrián Hernández-Mendoza ◽  
Aarón F. González-Córdova ◽  
Belinda Vallejo-Cordoba
Keyword(s):  
Dairy Products ◽  
Fermented Dairy Products ◽  
Fermented Dairy
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