scholarly journals Listeria monocytogenes in ham sliced in supermarkets in Recife city, Pernambuco state

2019 ◽  
Vol 86 ◽  
Author(s):  
Jéssica Martins de Andrade ◽  
Fernanda Maria de Lino Moura ◽  
Thayná Milena Siqueira Souza Silva ◽  
Elizabeth Sampaio de Medeiros
Keyword(s):  
Public Health ◽  
Listeria Monocytogenes ◽  
Great Risk ◽  
Gram Stain ◽  
Selective Agar ◽  
Camp Test

ABSTRACT: The aim of this study was to investigate Listeria monocytogenes in ham sliced in supermarkets in Recife city, Pernambuco state. In total, 40 samples of sliced ham were collected, and 25 g of ham was added to 225 mL of Demi Fraser broth. After incubation, 0.1 mL was inoculated in Fraser broth and, subsequently, sown in supplemented Listeria Selective Agar, based on Otaviani and Agosti. The following tests were carried out for confirmation purposes: Gram stain, motility test, catalase test and cAMP test. There was L. monocytogenes in 25% (10/40) of the samples. The presence of L. monocytogenes in ready-to-eat food, such as sliced ham, is likely related to lack of proper equipment-cleaning in supermarkets, a fact that poses great risk to public health.

Biofilm Formation and Associated Genes in Listeria Monocytogenes

2017 ◽  
Vol 12 (3) ◽  
Author(s):  
S. R. Warke ◽  
V. C. Ingle ◽  
N. V. Kurkure ◽  
P. A. Tembhurne ◽  
Minakshi Prasad ◽  
...  
Keyword(s):  
Public Health ◽  
Listeria Monocytogenes ◽  
Multiplex Pcr ◽  
Food Processing ◽  
Biofilm Formation ◽  
Milk Samples ◽  
Biofilm Production ◽  
Food Borne ◽  
Serious Infections ◽  
Microtiter Assay

Listeria monocytogenes, an opportunistic food borne pathogen can cause serious infections in immunocompromised individuals. L. monocytogenes is capable of producing biofilm on the surface of food processing lines and instruments.The biofilm transfers contamination to food products and impose risk to public health. In the present study biofilm producing ability of L. monocytogenes isolates were investigated phenotypically and genotypically by microtiter assay and multiplex PCR, respectively. Out of 38 L. monocytogenes isolates 14 were recovered from animal clinical cases, 12 bovine environment and 12 from milk samples. A total of 3 (21.42%) clinical, 2 (16.66%) environment and 3 (25%) milk samples respectively, revealed biofilm production in microtiter assay. Cumulative results showed that 23 (60.52%) out of 38 strains of L. monocytogenes were positive for luxS and flaA gene and 1 (2.63%) was positive only for the flaA gene.

scholarly journals Detection and Potential Virulence of Viable but Non-Culturable (VBNC) Listeria monocytogenes: A Review

2021 ◽  
Vol 9 (1) ◽  
pp. 194
Author(s):  
Nathan E. Wideman ◽  
James D. Oliver ◽  
Philip Glen Crandall ◽  
Nathan A. Jarvis
Keyword(s):  
Public Health ◽  
Listeria Monocytogenes ◽  
Viable Count ◽  
Vbnc State ◽  
Testing Methods ◽  
Tetrazolium Chloride ◽  
Definitive Evidence ◽  
Virulence Potential ◽  
Vbnc Bacteria ◽  
The Impact

The detection, enumeration, and virulence potential of viable but non-culturable (VBNC) pathogens continues to be a topic of discussion. While there is a lack of definitive evidence that VBNC Listeria monocytogenes (Lm) pose a public health risk, recent studies suggest that Lm in its VBNC state remains virulent. VBNC bacteria cannot be enumerated by traditional plating methods, so the results from routine Lm testing may not demonstrate a sample’s true hazard to public health. We suggest that supplementing routine Lm testing methods with methods designed to enumerate VBNC cells may more accurately represent the true level of risk. This review summarizes five methods for enumerating VNBC Lm: Live/Dead BacLightTM staining, ethidium monoazide and propidium monoazide-stained real-time polymerase chain reaction (EMA- and PMA-PCR), direct viable count (DVC), 5-cyano-2,3-ditolyl tetrazolium chloride-4′,6-diamidino-2-phenylindole (CTC-DAPI) double staining, and carboxy-fluorescein diacetate (CDFA) staining. Of these five supplementary methods, the Live/Dead BacLightTM staining and CFDA-DVC staining currently appear to be the most accurate for VBNC Lm enumeration. In addition, the impact of the VBNC state on the virulence of Lm is reviewed. Widespread use of these supplemental methods would provide supporting data to identify the conditions under which Lm can revert from its VBNC state into an actively multiplying state and help identify the environmental triggers that can cause Lm to become virulent. Highlights: Rationale for testing for all viable Listeria (Lm) is presented. Routine environmental sampling and plating methods may miss viable Lm cells. An overview and comparison of available VBNC testing methods is given. There is a need for resuscitation techniques to recover Lm from VBNC. A review of testing results for post VBNC virulence is compared

scholarly journals An overview of Listeria monocytogenes contamination in ready to eat meat, dairy and fishery foods

2017 ◽  
Vol 47 (2) ◽  
Author(s):  
Carla Susana Rodrigues ◽  
Cláudia Valéria Gonçalves Cordeiro de Sá ◽  
Cristiano Barros de Melo
Keyword(s):  
Public Health ◽  
Listeria Monocytogenes ◽  
Sodium Chloride ◽  
Food Safety ◽  
Pregnant Women ◽  
Foodborne Pathogen ◽  
Chloride Content ◽  
The Elderly ◽  
Fishery Products ◽  
Serious Disease

ABSTRACT: Listeria monocytogenes is a relevant foodborne pathogen in public health, responsible for outbreaks of listeriosis often associated to the consumption of ready to eat meat, dairy and fishery products. Listeriosis is a serious disease that can lead to death and mainly affect children, the elderly and immunocompromised individuals. In pregnant women causes abortion or neonatal listeriosis. In Brazil, ready to eat food are appreciated and increasingly consumed by the population. Furthermore, products such as sausages, bologna, hams and cheeses have characteristics such as pH, Aw and sodium chloride content that favor the development of L. monocytogenes during their shelf life. The purpose of this paper was to present an overview of L. monocytogenes contamination in different meat, dairy and fishery products that are ready for consumption and thereby support the adoption of strategies to mitigate this risk, contributing to achieve the appropriate level protection for the consumers and thus strengthen Brazil's food safety system.

scholarly journals Genome Sequence of theListeria monocytogenesFood Isolate HPB913, Collected in Canada in 1993

2016 ◽  
Vol 4 (5) ◽  
Author(s):  
Arthur W. Pightling ◽  
Hugh Rand ◽  
Errol Strain ◽  
Franco Pagotto
Keyword(s):  
Public Health ◽  
Listeria Monocytogenes ◽  
Food Safety ◽  
Genome Sequence ◽  
Sporadic Case ◽  
Foodborne Illness ◽  
Pathogenic Bacterium ◽  
Food Isolate ◽  
Serotype 1

Listeria monocytogenesis a pathogenic bacterium of importance to public health and food safety agencies. We present the genome sequence of the serotype 1/2aL. monocytogenesfood isolate HPB913, which was collected in Canada in 1993 as part of an investigation into a sporadic case of foodborne illness.

scholarly journals Laboratory Gram Stain Misidentifications of Neisseria meningitidis and Impact on Public Health Response to Meningococcal Disease

2016 ◽  
Vol 3 (suppl_1) ◽  
Author(s):  
Shrimati Datta ◽  
Anthony Moore ◽  
Jennifer Zipprich ◽  
Kathleen Winter ◽  
Kathleen Harriman
Keyword(s):  
Public Health ◽  
Neisseria Meningitidis ◽  
Meningococcal Disease ◽  
Gram Stain ◽  
Public Health Response ◽  
Health Response

Evaluation of Nisin-Coated Cellulose Casings for the Control of Listeria monocytogenes Inoculated onto the Surface of Commercially Prepared Frankfurters†‡

2004 ◽  
Vol 67 (5) ◽  
pp. 1017-1021 ◽  
Author(s):  
JOHN B. LUCHANSKY ◽  
JEFFREY E. CALL
Keyword(s):  
Listeria Monocytogenes ◽  
Surface Area ◽  
Internal Surface ◽  
Refrigerated Storage ◽  
Internal Surface Area ◽  
Appreciable Increase ◽  
Potassium Lactate ◽  
Selective Agar ◽  
Peptone Water ◽  
Sodium Diacetate

Commercially prepared frankfurters were formulated with and without ~1.4% potassium lactate and 0.1% sodium diacetate and were subsequently processed in cellulose casings coated with and without nisin (~50,000 IU per square inch of internal surface area) to control the outgrowth of Listeria monocytogenes during refrigerated storage. The frankfurters were inoculated with ~5 log CFU per package of a five-strain mixture of L. monocytogenes and then vacuum sealed before being stored at 4° C for 60 to 90 days. Surviving organisms were recovered and enumerated by rinsing each package with 18 ml of sterile 0.1% peptone water and plating onto MOX selective agar. The data for each of two trials were averaged. In packages that contained frankfurters formulated with potassium lactate and sodium diacetate and prepared in nisin-coated casings, L. monocytogenes levels decreased by 1.15 log CFU per package after 90 days of storage. L. monocytogenes levels decreased by 0.95 log CFU per package in frankfurters that were prepared in casings that were not coated with nisin. In packages of frankfurters that were formulated without potassium lactate and sodium diacetate and prepared in nisin-coated casings, L. monocytogenes levels decreased by 0.88 log CFU per package after 15 days of storage but then increased appreciablythereafter over a 60-day period of refrigerated storage. There was also an appreciable increase in pathogen numbers during 60 days of storage in otherwise similar frankfurters formulated without potassium lactate and sodium diacetate prepared in casings that were not coated with nisin. These data confirm that potassium lactate and sodium diacetate display listeriostatic activity as an ingredient of commercial frankfurters. These data also establish that cellulose casings coated with nisin display only moderate antilisterial activity in vacuum-sealed packages of commercially prepared frankfurters during storage at 4° C.

scholarly journals Public health impact of foodborne exposure to naturally occurring virulence-attenuated Listeria monocytogenes: inference from mouse and mathematical models

2019 ◽  
Vol 10 (1) ◽  
pp. 20190046 ◽  
Author(s):  
Alison Stout ◽  
Anna Van Stelten-Carlson ◽  
Hélène Marquis ◽  
Michael Ballou ◽  
Brian Reilly ◽  
...  
Keyword(s):  
Public Health ◽  
Listeria Monocytogenes ◽  
Food Safety ◽  
Protective Immunity ◽  
Health Benefit ◽  
Intestinal Barrier ◽  
Population Level ◽  
T Cell Response ◽  
Infection Model ◽  
Safety Testing

Listeriosis is a clinically severe foodborne disease caused by Listeria monocytogenes (Lm). However, approximately 45% of Lm isolates in food carry a virulence-attenuating single-nucleotide polymorphism in inlA , which normally facilitates crossing the intestinal barrier during the initial stages of infection. We hypothesized that (i) natural exposure to virulence-attenuated (vA) Lm strains through food can confer protective immunity against listeriosis attributable to fully virulent (fV) strains and (ii) current food safety measures to minimize exposure to both Lm strains may have adverse population-level outcomes. To test these hypotheses, we evaluated the host response to Lm in a mouse infection model and through mathematical modelling in a human population. After oral immunization with a murinized vA Lm strain, we demonstrated the elicitation of a CD8+ T-cell response and protection against subsequent challenge with an fV strain. A two-strain compartmental mathematical model of human exposure to Lm with cross-protective immunity was also developed. If food safety testing strategies preferentially identify and remove food contaminated by vA strains (potentially due to their common occurrence in foods and higher concentration in food compared to fV strains), the model predicted minimal public health benefit to potentially adverse effects. For example, reducing vA exposures by half, while maintaining fV exposures results in an approximately 6% rise in annual incidence.

Comparison of Selective Direct Plating Media for Enumeration and Recovery of L. monocytogenes from Cold-process (smoked) Fish

1992 ◽  
Vol 55 (11) ◽  
pp. 905-909 ◽  
Author(s):  
ROHINEE N. PARANJPYE ◽  
GRETCHEN A. PELROY ◽  
MARK E. PETERSON ◽  
FRANK T. POYSKY ◽  
PAUL J. HOLLAND ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Lithium Chloride ◽  
Indicator System ◽  
Water Phase ◽  
Direct Plating ◽  
Selective Media ◽  
Smoked Fish ◽  
Smoked Salmon ◽  
Selective Agar ◽  
Added Salt

Three selective media were evaluated for direct plating recovery and enumeration of Listeria monocytogenes in the presence of high levels of a variety of microorganisms occurring on cold-process (smoked) salmon products. Sliced salmon was brined to contain either no added salt, 3, or 5% water-phase NaCl, or 3 or 5% NaCl plus 140 ppm NaNO2. The slices were packaged in oxygen-permeable film or sealed under vacuum in oxygen-impermeable film, and stored at 10°C or 5°C until total microbial loads reached 106 to 109 CFU/g. Oxford formulation of Listeria selective agar and Lee's modification of Listeria selective agar achieved quantitative recovery of 102 cells per ml of L. monocytogenes strain Scott A in the presence of diluted slurries of these fish containing 104 to 108 CFU/ml of background organisms. A modification of lithium chloride-phenylethanol-moxalactam agar containing an iron-esculin indicator system sometimes failed because of interfering growth by the background microflora.

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