scholarly journals Detection of Airborne Lactococcal Bacteriophages in Cheese Manufacturing Plants

2010 ◽  
Vol 77 (2) ◽  
pp. 491-497 ◽  
Author(s):  
Daniel Verreault ◽  
Louis Gendron ◽  
Geneviève M. Rousseau ◽  
Marc Veillette ◽  
Daniel Massé ◽  
...  
Keyword(s):  
Lactococcus Lactis ◽  
Quantitative Pcr ◽  
Fermentation Process ◽  
Bacterial Populations ◽  
Manufacturing Plants ◽  
Air Samples ◽  
Bacterial Cultures ◽  
Personal Sampler ◽  
Heat Treated ◽  
Cyclone Sampler

ABSTRACTThe dairy industry adds starter bacterial cultures to heat-treated milk to control the fermentation process during the manufacture of many cheeses. These highly concentrated bacterial populations are susceptible to virulent phages that are ubiquitous in cheese factories. In this study, the dissemination of these phages by the airborne route and their presence on working surfaces were investigated in a cheese factory. Several surfaces were swabbed, and five air samplers (polytetrafluoroethylene filter, polycarbonate filter, BioSampler, Coriolis cyclone sampler, and NIOSH two-stage cyclone bioaerosol personal sampler) were tested. Samples were then analyzed for the presence of twoLactococcus lactisphage groups (936 and c2), and quantification was done by quantitative PCR (qPCR). Both lactococcal phage groups were found on most swabbed surfaces, while airborne phages were detected at concentrations of at least 103genomes/m3of air. The NIOSH sampler had the highest rate of air samples with detectable levels of lactococcal phages. This study demonstrates that virulent phages can circulate through the air and that they are ubiquitous in cheese manufacturing facilities.

scholarly journals Discrimination of Viable and Dead Fecal Bacteroidales Bacteria by Quantitative PCR with Propidium Monoazide

2009 ◽  
Vol 75 (9) ◽  
pp. 2940-2944 ◽  
Author(s):  
Sungwoo Bae ◽  
Stefan Wuertz
Keyword(s):  
Quantitative Pcr ◽  
Light Exposure ◽  
Bacteroides Fragilis ◽  
Extracellular Dna ◽  
Propidium Monoazide ◽  
Human Feces ◽  
Heat Treated ◽  
Pcr Conditions

ABSTRACT Propidium monoazide (PMA) was optimized to discriminate between viable and dead Bacteroides fragilis cells and extracellular DNA at different concentrations of solids using quantitative PCR. Conditions of 100 μM PMA and a 10-min light exposure also excluded DNA from heat-treated cells of nonculturable Bacteroidales in human feces and wastewater influent and effluent.

Application of quantitative PCR to the diagnosis and monitoring of Pseudomonas aeruginosa colonization in 5–18-year-old cystic fibrosis patients

2011 ◽  
Vol 60 (2) ◽  
pp. 157-161 ◽  
Author(s):  
Typhaine Billard-Pomares ◽  
Stéphanie Herwegh ◽  
Nathalie Wizla-Derambure ◽  
Dominique Turck ◽  
René Courcol ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Quantitative Pcr ◽  
Sputum Sample ◽  
Pulmonary Exacerbation ◽  
Additional Tool ◽  
Bacterial Cultures ◽  
Group A ◽  
Group B ◽  
Age Range

Early detection of Pseudomonas aeruginosa and early aggressive treatment are recommended to delay chronic infection in cystic fibrosis (CF) patients. The aim of this study was to assess a quantitative PCR (q-PCR) assay for the diagnosis of early P. aeruginosa colonization in 23 young CF patients (group A, age range 7–18 years) and to survey the eradication of P. aeruginosa in 10 young CF patients (group B, age range 5–18 years) after an initial antibiotic treatment. q-PCR results for consecutive sputum samples from each patient during a period of 18 months were compared with bacterial cultures during the same period plus an additional period of 12 months, and with concomitant clinical signs of pulmonary exacerbation. The q-PCR and bacterial cultures were negative for 17 of the 23 patients in group A and six of the 10 patients in group B during the study period. However, consecutive positive q-PCR results were observed for one patient in group A and three patients in group B, while the bacterial cultures for the same sputum sample remained negative. They preceded positive P. aeruginosa bacterial cultures at 7 and 8 months for two patients in group B. These positive results were associated with a worsening of the clinical status of patients, but pulmonary exacerbation appeared non-specific for the diagnosis of early P. aeruginosa colonization since pulmonary exacerbations were observed in patients in whom q-PCR or bacterial culture remained negative. In conclusion, q-PCR may be a useful additional tool to provide information on the P. aeruginosa status of CF patients.

Enumeration of specific bacterial populations in complex intestinal communities using quantitative PCR based on the chaperonin-60 target

2006 ◽  
Vol 64 (1) ◽  
pp. 46-62 ◽  
Author(s):  
Tim J. Dumonceaux ◽  
Janet E. Hill ◽  
Seth A. Briggs ◽  
Kingsley K. Amoako ◽  
Sean M. Hemmingsen ◽  
...  
Keyword(s):  
Quantitative Pcr ◽  
Bacterial Populations ◽  
Chaperonin 60

scholarly journals Quantitative PCR analysis of abundance of airborne propagules of Leptosphaeria species in air samples from different regions of Poland

Aerobiologia ◽  
2011 ◽  
Vol 28 (2) ◽  
pp. 199-212 ◽  
Author(s):  
Joanna Kaczmarek ◽  
Malgorzata Jedryczka ◽  
Hans J. Cools ◽  
Bruce D. L. Fitt ◽  
John A. Lucas ◽  
...  
Keyword(s):  
Quantitative Pcr ◽  
Pcr Analysis ◽  
Air Samples

scholarly journals Population Dynamics of Phenol-Degrading Bacteria in Activated Sludge Determined by gyrB-Targeted Quantitative PCR

1998 ◽  
Vol 64 (4) ◽  
pp. 1203-1209 ◽  
Author(s):  
Kazuya Watanabe ◽  
Satoshi Yamamoto ◽  
Sanae Hino ◽  
Shigeaki Harayama
Keyword(s):  
Population Dynamics ◽  
Activated Sludge ◽  
Quantitative Pcr ◽  
Pcr Amplification ◽  
Plate Count ◽  
Bacterial Populations ◽  
Pcr Product ◽  
Degrading Bacteria ◽  
Pcr Method ◽  
Kinetics Of

ABSTRACT A method for quantifying bacterial populations introduced into an activated-sludge microbial community is described. The method involves extraction of DNA from activated sludge, appropriate dilution of the extracted DNA with DNA extracted from nonintroduced activated sludge, PCR amplification of a gyrB gene fragment from the introduced strain with a set of strain-specific primers, and quantification of the electrophoresed PCR product by densitometry. The adequacy of the method was examined by analyzing the population dynamics of two phenol-degrading bacteria, Pseudomonas putida BH and Comamonas sp. strain E6, that had been introduced into phenol-digesting activated sludge. The density of each of the two populations determined by the PCR method immediately after the introduction was consistent with the density estimated from a plate count of the inoculum. This quantitative PCR method revealed different population dynamics for the two strains in the activated sludge under different phenol-loading conditions. The behavior of both of these strains in the activated sludge reflected the growth kinetics of the strains determined in laboratory axenic cultures.

scholarly journals Proteolytic Lactococcus lactis and Lipolytic Enterococcus durans of Dairy Origin as Meat Functional Starter Cultures

2021 ◽  
Vol 59 (1) ◽  
Author(s):  
Mirna Mrkonjic Fuka ◽  
Ivica Kos ◽  
Ana Zgomba Maksimovic ◽  
Melita Bačić ◽  
Irina Tanuwidjaja
Keyword(s):  
Survival Rate ◽  
Wild Boar ◽  
Lactococcus Lactis ◽  
Starter Cultures ◽  
Small Scale ◽  
Probiotic Properties ◽  
Enterococcus Durans ◽  
Bacterial Cultures ◽  
Fermented Sausages ◽  
Wild Boar Meat

Research background. As fermentation is an integral feature of both, dry sausage and cheese production this has led to the evaluation of bacterial cultures Lactococcus lactis subsp. cremoris (LL8307) and Enterococcus durans (ED0207) originally isolated from artisanal Croatian hard type cheese to diversify the range of flavour of dry fermented sausages and to increase their microbiological safety. Both strains were chosen for their high or medium acidifying, proteolytic and/or lipolytic activity and bioprotective potential after step-by-step selection of wild isolates. Therefore, this study aimed to evaluate the survival rate of selected starter cultures in wild boar meat sausages during the ripening period of 40 days at a local small-scale facility under artisanal conditions as well as their influence on sausages’ quality parameters. Experimental approach. Safety, biotechnological and probiotic properties of twenty-three enterococcal and lactococcal isolates of dairy origin were studied. Based on those results two best candidates were selected and applied to the meat batter during the artisanal wild boar meat sausages preparation where their survival rate, the effect on physicochemical, microbiological and sensorial properties and histamine content were evaluated. Results and conclusions. As revealed by rep-PCR, native starter cultures survived up to 15 days of ripening and were either absent (LL8307) or reduced by 80 % (ED0207) in final products. The application of native starter cultures rapidly decreased pH (p<0.05) leading to the significantly lower load of E.coli, coliforms and Enterobacteriaceae in ready-to-eat sausages prepared by the addition of starter cultures (3.04-3.94 log CFU/g) in comparison to the control (3.88-5.00 log CFU/g). Analysis of hedonic test data revealed that some of the sensory traits (odour, flavour, juiciness) of treatments with starter cultures were highly liked by the higher share of consumers. The results suggest that these starter cultures would represent a valuable tool to improve the homogeneity of artisanal manufacture and hygienic quality of fermented sausages and can be safely used for food application. Novelty and ccientific contribution. This is the first study to deeply explore the biotechnological potential of bacterial cultures isolated from artisanal Croatian cheese as functional starter cultures for high-quality game meat sausages production.

Alternaria toxins of the alternariol type are not metabolised by human faecal microbiota

2016 ◽  
Vol 9 (1) ◽  
pp. 41-50 ◽  
Author(s):  
A. Lemke ◽  
B. Burkhardt ◽  
D. Bunzel ◽  
E. Pfeiffer ◽  
M. Metzler ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Brain Heart Infusion ◽  
Bacterial Cells ◽  
Faecal Microbiota ◽  
Anaerobic Conditions ◽  
Bacterial Cultures ◽  
Alternaria Toxins ◽  
Heat Treated ◽  
Human Volunteers ◽  
Pure Bacterial Cultures

The metabolism of the Alternaria toxins alternariol (AOH), alternariol-9-O-methyl ether (AME) and altenuene (ALT) by the microbiota present in faeces from three human volunteers was studied. Faecal cultures were prepared as a 5% faeces suspension in brain-heart infusion broth and incubated with 50 μM of the toxins under anaerobic conditions for 72 h at 37 °C. The metabolism of AOH was also studied in pure bacterial cultures with either Escherichia coli DH5α or Lactobacillus plantarum BFE 5092 for 72 h at 37 °C. The three parent toxins were stable in uninoculated, heat-treated medium over a 72 h incubation period with a recovery of more than 90%. As a control for the activity of the faecal microbiota, the isoflavone daidzein was incubated with the faecal cultures and was transformed to its expected metabolites. In contrast, no metabolites of AOH, AME and ALT could be detected in the faecal cultures from the same volunteers, indicating that the gut microbiota was not capable of metabolising these substances. The Alternaria toxins could be shown to be at least partially bound to bacterial cells in a non-covalent manner, which may serve as a mechanism for their removal from the gut.

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