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Fate of Listeria monocytogenes on fully ripened Greek Graviera cheese stored at 4, 12, or 25 degrees C in air or vacuum packages: in situ PCR detection of a cocktail of bacteriocins potentially contributing to pathogen inhibition.

https://arctichealth.org/en/permalink/ahliterature151703
Source
J Food Prot. 2009 Mar;72(3):531-8
Publication Type
Article
Date
Mar-2009
Author
Eleni Giannou
Athanasia Kakouri
Bojana Bogovic Matijasic
Irena Rogelj
John Samelis
Author Affiliation
National Agricultural Research Foundation, Dairy Research Institute, Katsikas, 45221 Ioannina, Greece.
Source
J Food Prot. 2009 Mar;72(3):531-8
Date
Mar-2009
Language
English
Publication Type
Article
Keywords
Bacteriocins - isolation & purification
Cheese - microbiology
Colony Count, Microbial
Consumer Product Safety
Enterococcus faecium - metabolism
Food Microbiology
Food Packaging - methods
Food Preservation - methods
Humans
Listeria monocytogenes - drug effects - growth & development
Oxygen - metabolism
Polymerase Chain Reaction - methods
Risk assessment
Temperature
Time Factors
Vacuum
Abstract
The behavior of Listeria monocytogenes on fully ripened Greek Graviera cheese was evaluated. Three batches (A, B, and C) were tested. Batches A and C were prepared with a commercial starter culture, while in batch B the starter culture was combined with an enterocin-producing Enterococcus faecium Graviera isolate. Cheese pieces were surface inoculated with a five-strain cocktail of L. monocytogenes at ca. 3 log CFU/cm2, packed under air or vacuum conditions, stored at 4, 12, or 25 degrees C, and analyzed after 0, 3, 7, 15, 30, 60, and 90 days. L. monocytogenes did not grow on the cheese surface, regardless of storage conditions. However, long-term survival of the pathogen was noted in all treatments, being the highest (P
PubMed ID
19343941 View in PubMed
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Sample preparation and DNA extraction procedures for polymerase chain reaction identification of Listeria monocytogenes in seafoods.

https://arctichealth.org/en/permalink/ahliterature11066
Source
Int J Food Microbiol. 1997 Apr 15;35(3):275-80
Publication Type
Article
Date
Apr-15-1997
Author
A. Agersborg
R. Dahl
I. Martinez
Author Affiliation
Norwegian Institute of Fisheries and Aquaculture N-9005 Tromso, Norway.
Source
Int J Food Microbiol. 1997 Apr 15;35(3):275-80
Date
Apr-15-1997
Language
English
Publication Type
Article
Keywords
Animals
Base Sequence
DNA, Bacterial - analysis - chemistry - genetics
Decapoda (Crustacea) - microbiology
Detergents - pharmacology
Electrophoresis, Agar Gel
Endopeptidase K - pharmacology
Fish Products - microbiology
Food Microbiology
Food Poisoning - diagnosis - epidemiology - etiology
Gene Amplification
Heat
Humans
Listeria monocytogenes - drug effects - genetics - isolation & purification
Muramidase - pharmacology
Norway - epidemiology
Octoxynol - pharmacology
Polymerase Chain Reaction - methods
Prevalence
Research Support, Non-U.S. Gov't
Sensitivity and specificity
Time Factors
Abstract
Five grams of seafood products were inoculated with one to 500 viable or 10(9) heat-killed cells of Listeria monocytogenes. The presence of the pathogen was detected by the polymerase chain reaction (PCR) with primers specific for fragments of the listeriolysin O (hly) gene (two sets) and for the invasion-associated protein (iap) gene (one set). For DNA preparation, boiling, either alone or in combination with lysozyme and proteinase K treatment, was not always sufficient to lyse L. monocytogenes, while treatment with Triton X-100 produced consistently good DNA suitable for amplification. To avoid false-negative and false-positive results, 48 h incubations were necessary and a subculturing step after an initial 24 h incubation greatly improved the results. The primers that amplified regions of the listeriolysin O gene gave clearer and stronger products than primers for the invasion-associated protein gene. Using this method we were able to detect one to five L. monocytogenes cells in 5 g of product in a total of 55 h.
PubMed ID
9105938 View in PubMed
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