Rapid Detection of Lactobacillus kefiranofaciens in Kefir Grain and Kefir Milk Using Newly Developed Real-Time PCR

Kim, Dong‐Hyeon; Chon, Jung‐Whan; Kim, Hong-Seok; Yim, Jin-Hyeok; Kim, Hyun‐Sook

doi:10.4315/0362-028x.jfp-14-329

Cited by 20 publications

(11 citation statements)

References 27 publications

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“…The average level of background microflora of the 82 beef samples was 4.53±2.67 log CFU per gram, suggesting that the real-time PCR assay could detect the targeted organism even when it was hidden by other background organisms in the culture media. The same phenomenon was observed in the real-time PCR assays for the detection of Listeria monocytogenes and Lactobacillus kefiranofaciens in food samples with high levels of background microflora (10,19). In addition, the results of the real-time PCR assay for detection of C. perfringens could be obtained within 30 h, whereas the conventional culture method requires 96 h (Fig.…”

Section: Resultssupporting

confidence: 66%

Prevalence and toxin type of Clostridium perfringens in beef from four different types of meat markets in Seoul, Korea

Jeong

Kim

Kang

et al. 2017

Food Sci Biotechnol

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Beef is the primary source of foodborne poisoning caused by . We investigated the prevalence of in retail beef from four different types of meat markets in Seoul using a standard culture method and real-time PCR assay. From June to September 2015, 82 beef samples were collected from 6 department stores (=12), 14 butcher shops (=28), 16 traditional markets (=32), and 5 supermarkets (=10). The culture method and real-time PCR assay revealed that 4 (4.88%) and 10 (12.20%) samples were positive for C. perfringens, respectively. The beef purchased from the department store showed the highest prevalence (16.67%), followed by the traditional market (3.12%), butcher shop (3.57%), and supermarket (0%) (>0.05). All isolates were type A and negative for the enterotoxin gene. In conclusion, the real-time PCR assay used in this study could be useful for rapid detection and screening of in beef.

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Section: Resultssupporting

confidence: 66%

Prevalence and toxin type of Clostridium perfringens in beef from four different types of meat markets in Seoul, Korea

Jeong

Kim

Kang

et al. 2017

Food Sci Biotechnol

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“…L. kefiri and L. kefiranofaciens have been recognised as indicator microorganisms of kefir and reported to have pivotal roles in the beneficial health effects of kefir (CODEX Alimentarius Commission 2003; Chen et al 2012; Kim et al 2015c, 2016). It is interesting that culture supernatnant of L. kefiri exerted stronger inhibition on C. sakazakii than that of L. kefiranofaciens , although the supernatnant of L. kefiranofaciens has lower pH and higher titrable acidity than that of L. kefiri .…”

Section: Resultsmentioning

confidence: 99%

Culture supernatant produced by Lactobacillus kefiri from kefir inhibits the growth of Cronobacter sakazakii

Kim

Jeong

Song

et al. 2018

Journal of Dairy Research

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Cronobacter sakazakii is a life-threatening foodborne pathogen found in powdered infant formula and dairy products. Kefir is a dairy probiotic product and its antimicrobial activity against C. sakazakii was reported in our previous study. To identify key microorganisms that mediate growth suppression, we tested the antimicrobial activity of culture supernatants derived from lactic acid bacteria found in kefir. Lactobacillus kefiri DH5, L. kefiranofaciens DH101, and Bifidobacterium longum 720 (a commercial probiotic strain that served as a positive control) all significantly inhibited the growth of C. sakazakii ATCC 29544, delaying the initiation of exponential growth from 3 to 9 h in the nutrient broth. Among them, L. kefiri DH5 exerted the strongest antimicrobial effects against C. sakazakii, showing bactericidal effect at the addition of 300 µl of supernatant in 1 ml of nutrient broth. Interestingly, the supernatant of L. kefiri DH5 has higher pH and lower titrable acidity than that of L. kefiranofaciens DH101, suggesting metabolites produced by heterofermentation of L. kefiri acted more effectively to antagonise the growth of C. sakazakii. In addition, the supernatant of L. kefiri DH5 induced the leakage of cytoplasmic materials including nucleic acid and proteins, suggesting L. kefiri DH5 disrupted the cellular membrane integrity of C. sakazakii. Considering that pH neutralisation reduced the L. kefiri-dependent growth suppression, it is inferred that this activity is mainly due to organic acids produced during the fermentation process.

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“…Although not yet confirmed in vivo, several strains isolated from kefir have been shown to adhere to human enterocyte-like Caco-2 cells, indicating a potential ability to colonise the human gut [50]. Kefir, or its constituent strains, have also been shown to have a considerable impact on the gut microbiota population with increases in Lactobacillus , Lactococcus and Bifidobacterium concentrations, and reductions in Proteobacteria and Enterobacteriaceae concentrations, being demonstrated in numerous animal studies [51,52,53]. Furthermore, one study found higher concentrations of Firmicutes , Bacteroidetes and Prevotella , as well as a higher stool weight and stool water, in mice administered Lactobacillus kefiranofaciens (but not kefir per se ), a common strain found in kefir grains, compared to control [52].…”

Section: Kefirmentioning

confidence: 99%

Fermented Foods: Definitions and Characteristics, Impact on the Gut Microbiota and Effects on Gastrointestinal Health and Disease

et al. 2019

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Fermented foods are defined as foods or beverages produced through controlled microbial growth, and the conversion of food components through enzymatic action. In recent years, fermented foods have undergone a surge in popularity, mainly due to their proposed health benefits. The aim of this review is to define and characterise common fermented foods (kefir, kombucha, sauerkraut, tempeh, natto, miso, kimchi, sourdough bread), their mechanisms of action (including impact on the microbiota), and the evidence for effects on gastrointestinal health and disease in humans. Putative mechanisms for the impact of fermented foods on health include the potential probiotic effect of their constituent microorganisms, the fermentation-derived production of bioactive peptides, biogenic amines, and conversion of phenolic compounds to biologically active compounds, as well as the reduction of anti-nutrients. Fermented foods that have been tested in at least one randomised controlled trial (RCT) for their gastrointestinal effects were kefir, sauerkraut, natto, and sourdough bread. Despite extensive in vitro studies, there are no RCTs investigating the impact of kombucha, miso, kimchi or tempeh in gastrointestinal health. The most widely investigated fermented food is kefir, with evidence from at least one RCT suggesting beneficial effects in both lactose malabsorption and Helicobacter pylori eradication. In summary, there is very limited clinical evidence for the effectiveness of most fermented foods in gastrointestinal health and disease. Given the convincing in vitro findings, clinical high-quality trials investigating the health benefits of fermented foods are warranted.

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Rapid Detection of Lactobacillus kefiranofaciens in Kefir Grain and Kefir Milk Using Newly Developed Real-Time PCR

Cited by 20 publications

References 27 publications

Prevalence and toxin type of Clostridium perfringens in beef from four different types of meat markets in Seoul, Korea

Prevalence and toxin type of Clostridium perfringens in beef from four different types of meat markets in Seoul, Korea

Culture supernatant produced by Lactobacillus kefiri from kefir inhibits the growth of Cronobacter sakazakii

Fermented Foods: Definitions and Characteristics, Impact on the Gut Microbiota and Effects on Gastrointestinal Health and Disease

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