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 ◽  
...  

  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.

Author(s):  
Le Quyen Pham Thi ◽  
Trong Pham Nhu ◽  
Linh Nguyen Thuy ◽  
Trung Nguyen Thanh ◽  
◽  
...  

Lactobacillus has a biological effect to supports digestion system. Therefore, it is widely used in dairy products such as yoghurt, food additives and pharmaceuticals. Lactobacillus acidophilus (L. acidophilus) is often used in fermented dairy products such as yoghurt and functional products. However, in Vietnam, there is currently no standard method for quantifying L. acidophilus. In this study, a quantitative method of L. acidophilus using real-time PCR based on a specific fragment of Hsp gene was developed. The limit of quantification of the method is 105 CFU/g/mL that is suitable for quality assessment of probiotic products with greater quality claims than 106 CFU/g/mL. The specificity of the method is of 100% when compared with nonspecific strains and repeatability is of Sr < 0.125 in accordance with the requirements of ISO 16140: 2005 and AOAC: 2016 annex F for method evaluation microbiology.


2007 ◽  
Vol 56 (10) ◽  
pp. 1346-1349 ◽  
Author(s):  
Tadayuki Iwase ◽  
Keiko Seki ◽  
Hitomi Shinji ◽  
Yoshimitsu Mizunoe ◽  
Shogo Masuda

Staphylococcus capitis, Staphylococcus haemolyticus and Staphylococcus warneri are coagulase-negative staphylococci. Each species has different characteristics, and a difference in pathology is also seen in compromised hosts. Therefore, the development of a species-specific simple detection method for the identification of these staphylococci is important. Here, a species-specific real-time PCR assay is reported that targets the superoxide dismutase A-encoding gene of these bacteria. Primers were designed with a base that was non-complementary with regard to the other bacteria. This base was at the 3′ end of the primer (3′ mismatch primer) and conferred high specificity. These primers were then evaluated using real-time PCR. They reacted only with the target bacterium. In addition, stable quantitative reactions were observed when experiments were performed using genomic DNA extracted from varying numbers of staphylococci cells (101–107 cells). These results indicate that this method is useful for the identification and quantitative analysis of S. capitis, S. haemolyticus and S. warneri.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Kamil Rashidi ◽  
Bahman Razi ◽  
Mina Darand ◽  
Azadeh Dehghani ◽  
Parisa Janmohammadi ◽  
...  

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.


2012 ◽  
Vol 194 (9) ◽  
pp. 749-757 ◽  
Author(s):  
Catarina Churro ◽  
Paulo Pereira ◽  
Vitor Vasconcelos ◽  
Elisabete Valério

Sign in / Sign up

Export Citation Format

Share Document