Role of osmolytes in adaptation of osmotically stressed and chill-stressed Listeria monocytogenes grown in liquid media and on processed meat surfaces.

ABSTRACT In alkaline conditions, Listeria monocytogenes cells develop higher proportions of branched-chain fatty acids (FAs), including more anteiso forms. In acid conditions, the opposite occurs. Reduced growth of pH-sensitive mutants at adverse pH (5.0/9.0) was alleviated by the addition of 2-methylbutyrate (an anteiso-FA precursor), suggesting that anteiso-FAs are important in adaptation to adverse pH. The balance between anteiso- and iso-FAs may be more important than changes in the amounts and/or degrees of saturation of FAs in pH adaptation.

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Differential mechanisms of intracellular killing of Mycobacterium avium and Listeria monocytogenes by activated human and murine macrophages. The role of nitric oxide

Clinical & Experimental Immunology ◽

10.1111/j.1365-2249.1993.tb05895.x ◽

2008 ◽

Vol 91 (2) ◽

pp. 277-281 ◽

Cited By ~ 80

Author(s):

L. E. BERMUDEZ

Keyword(s):

Nitric Oxide ◽

Listeria Monocytogenes ◽

Mycobacterium Avium ◽

Intracellular Killing ◽

Murine Macrophages

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The effect of processed meat and meat starter cultures on gastrointestinal colonization and virulence of Listeria monocytogenes in mice

International Journal of Food Microbiology ◽

10.1016/s0168-1605(02)00400-2 ◽

2003 ◽

Vol 84 (3) ◽

pp. 255-261 ◽

Cited By ~ 26

Author(s):

M. Mahoney ◽

A. Henriksson

Keyword(s):

Listeria Monocytogenes ◽

Starter Cultures ◽

Processed Meat ◽

Gastrointestinal Colonization

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Control of Listeria monocytogenes with Combined Antimicrobials after Postprocess Contamination and Extended Storage of Frankfurters at 4° C in Vacuum Packages

Journal of Food Protection ◽

10.4315/0362-028x-65.2.299 ◽

2002 ◽

Vol 65 (2) ◽

pp. 299-307 ◽

Cited By ~ 111

Author(s):

JOHN SAMELIS ◽

GERARD K. BEDIE ◽

JOHN N. SOFOS ◽

KEITH E. BELK ◽

JOHN A. SCANGA ◽

...

Keyword(s):

Listeria Monocytogenes ◽

Sodium Acetate ◽

Sensory Quality ◽

Sodium Lactate ◽

Hot Water ◽

Processed Meat ◽

C Storage ◽

Heat Treated ◽

Cured Meat ◽

Sodium Diacetate

Contamination of ready-to-eat foods, such as frankfurters, with Listeria monocytogenes, is a major concern that needs to be addressed in order to enhance the safety of these products. The objective of this study was to determine the effectiveness of combinations of antimicrobials included in the formulation of frankfurters against L. monocytogenes inoculated (103 to 104 CFU/cm2) on their surface after peeling and before vacuum packaging. In addition, the antilisterial effect of immersing the packaged products, prepared with or without antimicrobials, in hot (75 or 80°C) water for 30 to 90 s was evaluated. Samples were stored at 4°C for up to 120 days and periodically analyzed for pH and for microbial growth on tryptic soy agar plus 0.6% yeast extract (TSAYE) and PALCAM agar. Sodium lactate (1.8%; 3% of a 60% commercial solution) used alone inhibited growth of L. monocytogenes for 35 to 50 days, whereas when used in combination with 0.25% sodium acetate, sodium diacetate, or glucono-δ-lactone (GDL), sodium lactate inhibited growth throughout storage (120 days). Immersing packaged frankfurters in hot water (80°C, 60 s) reduced inoculated populations of L. monocytogenes by 0.4 to 0.9 log CFU/cm2 and reduced its growth by 1.1 to 1.4 log CFU/cm2 at 50 to 70 days of storage in samples containing 1.8% sodium lactate alone. However, immersion of frankfurters containing no antimicrobials in hot water (75 or 80°C) did not inhibit growth of the pathogen for more than 10 to 20 days, unless one frankfurter was placed per bag and heat treated for 90 s. These results indicate that the inclusion of 1.8% sodium lactate with 0.25% sodium acetate, sodium diacetate, or GDL in cured meat formulations may control L. monocytogenes growth during refrigerated (4°C) storage. Additional studies are required to evaluate the effects of these combinations at abusive temperatures of storage, as well as on additional processed meat formulations and on the sensory quality and shelf life of products.

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Listeria monocytogenes: An emerging food-borne pathogen and its public health implications

The Journal of Infection in Developing Countries ◽

10.3855/jidc.6616 ◽

2016 ◽

Vol 10 (02) ◽

pp. 149-154 ◽

Cited By ~ 15

Author(s):

Waffa W Reda ◽

Khaled Abdel-Moein ◽

Ahmed Hegazi ◽

Yasmin Mohamed ◽

Khaled Abdel-Razik

Keyword(s):

Listeria Monocytogenes ◽

Raw Milk ◽

Food Samples ◽

Food Borne ◽

Contaminated Food ◽

Luncheon Meat ◽

Stool Specimens ◽

Polymerase Chain ◽

Minced Meat

Introduction: Listeria monocytogenes is considered one of the most important food-borne pathogens transmitted to humans via contaminated food. The aim of the present study was to demonstrate the importance of L. monocytogenes as a food-borne pathogen. Methodology: A total of 340 samples were collected from different localities in El Giza Governorate, Egypt, to check the occurrence of L. monocytogenes in that area. The collected samples comprised 250 food samples, 40 swabs from food refrigerators, and 50 stool specimens from diarrheic children. L. monocytogenes was isolated from the examined samples according to the International Organization for Standardization. The isolates were tested biochemically using Listeria Microbact 12L and confirmed by polymerase chain reaction. Results: The isolation rates of L. monocytogenes were 8% in beef burger, 4% in minced meat, 4% in luncheon meat, while sausage samples were all negative. Eight percent of raw milk samples were positive for L. monocytogenes, whereas cheese samples and refrigerator swabs were negative. Only Listeria grayi was isolated from human stools (2.5%). Conclusion: The high isolation rates of L. monocytogenes among the examined food stuffs highlight the crucial role of food as an important vehicle for this pathogen. More efforts should be made to ensure safe handling and processing of these foods to reduce the transmission of L. monocytogenes to humans.

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Review on Pathogenic Bacteria Listeria monocytogenes, The Detection and The Sequencing Gene Methods Isolated from Meat Products

Journal of Applied Food Technology ◽

10.17728/jaft.6460 ◽

2019 ◽

Vol 6 (2) ◽

Author(s):

Bhakti Etza Setiani ◽

Yoyok Budi Pramono ◽

Lutfi Purwitasari

Keyword(s):

Listeria Monocytogenes ◽

Pathogenic Bacteria ◽

Meat Product ◽

Meat Products ◽

Processed Meat ◽

Confirmation Test ◽

Optimum Ph ◽

Bacterium Species ◽

Genotypic Identification ◽

Ph Range

A study was conducted to review on pathogenic bacteria Listeria monocytogenes, the detection and the sequencing gene methods isolated from meat products, compare selected methods that detect the presence of Listeria monocytogenes in selected raw and processed meat products. Results indicate that Listeria monocytogenenes (originally named Bacterium monocytogenes) is a gram-positive, non-sporeforming, highly mobile, rod-type, and facultative anaerobic bacterium species. It can grow under temperatures between -1.5°C to 45°C and at pH range between 4.4 and 9.4, with the optimum pH of 7. Rapid methods (PCR based and VIDAS-LDUO®) detected Listeria monocytogenes faster than the conventional method. It was also gathered that Phenotypic identification and Genotypic identification are two types of confirmation test for Listeria monocytogenes. Listeria monocytogenenes can be found in raw meat and meat product because of environmental contamination, cross contamination or error process.

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The inlA Gene of Listeria monocytogenesLO28 Harbors a Nonsense Mutation Resulting in Release of Internalin

Infection and Immunity ◽

10.1128/iai.66.7.3420-3422.1998 ◽

1998 ◽

Vol 66 (7) ◽

pp. 3420-3422 ◽

Cited By ~ 85

Author(s):

Renaud Jonquières ◽

Hélène Bierne ◽

Jérôme Mengaud ◽

Pascale Cossart

Keyword(s):

Cell Adhesion ◽

Listeria Monocytogenes ◽

Virulence Factor ◽

Adhesion Molecule ◽

Nonsense Mutation ◽

Cell Adhesion Molecule ◽

Culture Medium ◽

Surface Protein ◽

Truncated Protein

ABSTRACT Internalin is a surface protein that mediates entry ofListeria monocytogenes EGD into epithelial cells expressing the cell adhesion molecule human E-cadherin or its chicken homolog, L-CAM, which act as receptors for internalin. After observing that entry of L. monocytogenes LO28 into S180 fibroblasts, in contrast to that of EGD, did not increase after transfection with L-CAM, we examined both the expression and the structure of internalin in strain LO28. We discovered a nonsense mutation in inlA which results in a truncated protein released in the culture medium. Mutations leading to release of internalin were also detected in clinical and food isolates. These results question the role of internalin as a virulence factor in murine listeriosis.

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