DIAGNOSTIC PREPARATIONS FOR DETERMINING THE SPECIES OF THE BACTERIA LISTERIA MONOCYTOGENES

2021 ◽  
Author(s):  
V. G. Lobanova ◽  
Keyword(s):  
Listeria Monocytogenes ◽  
Dairy Products ◽  
Pathogenic Bacteria ◽  
Food Products ◽  
Nutrient Media ◽  
Microbiological Study ◽  
Highly Sensitive

This article presents a work on the microbiological study of food products for the presence of pathogenic bacteria Listeria monocytogenes, which can cause listeriosis in humans if sanitary and hygienic rules and regulations are not followed. Highly sensitive and specific nutrient media make it possible to quickly and efficiently test meat, vegetable and dairy products for the detection of Listeria monocytogenes.

scholarly journals Prevalence of Listeria monocytogenes in raw bovine milk and milk products from central highlands of Ethiopia

2015 ◽  
Vol 9 (11) ◽  
pp. 1204-1209 ◽  
Author(s):  
Eyasu Tigabu Seyoum ◽  
Daniel Asrat Woldetsadik ◽  
Tesfu Kassa Mekonen ◽  
Haile Alemayehu Gezahegn ◽  
Wondwossen Abebe Gebreyes
Keyword(s):  
Listeria Monocytogenes ◽  
Urban Areas ◽  
Dairy Products ◽  
Pathogenic Bacteria ◽  
Bovine Milk ◽  
Raw Milk ◽  
Milk Product ◽  
Milk Products ◽  
Pasteurized Milk ◽  
Processing Plants

Introduction: Listeria monocytogenes is of major significance in human and veterinary medicine. Most human Listeria infections are foodborne and the association of contaminated milk and dairy produce consumption with human listeriosis is noteworthy. In Ethiopia, there is limited data regarding the prevalence of L. monocytogenes in raw bovine milk and dairy products. The aim of this study was, therefore, to determine the prevalence of L. monocytogenes in raw bovine milk and dairy produce. Methodology: A total of 443 milk and milk product samples were microbiologically analyzed following methods recommended by the U.S. Food and Drug Administration Bacteriological Analytical Manual to isolate Listeria spp. Results: The overall prevalence of Listeria spp. was 28.4% and specifically that of L. monocytogenes was 5.6%. Taking the prevalence of Listeria spp. into consideration, cheese was found to be highly contaminated at 60%, followed by pasteurized milk samples (40%), raw milk (18.9%) and yoghurt (5%). Considering the prevalence of Listeria monocytogenes only, raw milk had the lowest contamination while cheese had the highest, followed by pasteurized milk and yoghurt. Conclusions: Raw milk and milk products produced in urban and peri-urban areas of central Ethiopia were contaminated with pathogenic bacteria, L. monocytogenes. The detection of this pathogen in raw milk and milk products warrants an urgent regulatory mechanism to be put in place and also the potential role of milk processing plants in the contamination of dairy products should be investigated.

A Survey of Iceberg Lettuce for the Presence of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in Japan

2011 ◽  
Vol 74 (9) ◽  
pp. 1543-1546 ◽  
Author(s):  
SHIGENOBU KOSEKI ◽  
YASUKO MIZUNO ◽  
SUSUMU KAWASAKI ◽  
KAZUTAKA YAMAMOTO
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Pathogenic Bacteria ◽  
Coliform Bacteria ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Iceberg Lettuce ◽  
Highly Sensitive ◽  
Plate Counts ◽  
Pcr Method

No information has been available on the prevalence of pathogens in fresh produce in Japan. In the present study, information was collected on the occurrence of contamination by Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in iceberg lettuce in a Japanese retail store. A total of 419 samples of lettuce that had been harvested in different districts and/or by different producers from July 2008 to March 2009 were examined. A multiplex PCR method was used to simultaneously identify the three bacterial pathogens. No pathogenic bacteria, including Salmonella, E. coli O157:H7, and L. monocytogenes, were detected from any of the samples with this highly sensitive and validated procedure. The aerobic bacteria plate counts and coliform bacteria counts in lettuce throughout the examination period did not show any seasonal trends, and the numbers were comparable to those reported by others from around the world. Based on the results of this study, we concluded that none of the three major pathogens were present in this limited survey of iceberg lettuce sold by a retailer in Japan.

scholarly journals Assessment of listeria monocytogenes, staphylococcus aureus and salmonella SPP. Contamination in dairy samples collected in Gia Lam and Ba Vi, Hanoi early 2019

2019 ◽  
Vol 2 (4) ◽  
pp. 22-32
Author(s):  
Minh Huyen Nguyen Thi ◽  
Hoa Tran Thi ◽  
Tuyet Lan Ninh Thi ◽  
Hien Tran Thi ◽  
◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Dairy Products ◽  
Pathogenic Bacteria ◽  
Raw Milk ◽  
Accurate Method ◽  
Salmonella Spp ◽  
Pasteurized Milk ◽  
Milk Samples ◽  
Milk And Dairy Products

Milk and dairy products from dairy farms around Hanoi greatly contribute to the consumed milk quantity in Hanoi. The use of fresh milk or pasteurized milk becomes more and more popular in the daily life of local people. Milk and dairy products were widely sold in numerous stores, particularly in Xuan Mai, Ba Vi, Phu Dong and Gia Lam. However, there have not yet been any studies to assess the pathogenic bacterial contamination of these products. In our study, 49 samples including 23 raw milk samples, 12 pasteurized milk samples, and 14 yogurt samples were collected in order to examine the presence of food­born pathogenic bacteria such as Listeria monocytogenes, Staphylococcus aureus, Salmonella spp. using PCR method. This fast and accurate method works based on the specific amplification of tested bacterial DNA. The results showed that one of the samples may contain Staphylococcus aureus while another may be contaminated with Listeria monocytogenes. None of the samples was contaminated with Salmonella spp. The results were confirmed by gene sequencing.

scholarly journals Probiotic Delivery through Non-Dairy Plant-Based Food Matrices

Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 599
Author(s):  
D. M. D. Rasika ◽  
Janak K. Vidanarachchi ◽  
Selma F. Luiz ◽  
Denise Rosane Perdomo Azeredo ◽  
Adriano G. Cruz ◽  
...  
Keyword(s):  
Functional Properties ◽  
Dairy Products ◽  
Microbiological Quality ◽  
Health Benefit ◽  
Food Products ◽  
Quality Characteristics ◽  
Dairy Plant ◽  
Food Matrices ◽  
Probiotic Food ◽  
Probiotic Delivery

Probiotics are live microorganisms which, when administered in adequate amounts, confer a health benefit on the host. Traditionally, dairy products are the major and most popular probiotic carriers. At present, there is a growing demand for non-dairy probiotic products. Both fermented and non-fermented non-dairy plant-based food products are becoming highly appealing to both dairy and non-dairy consumers worldwide. Non-dairy plant-based food matrices such as fruits, vegetables, plant-based milk, cereals, and legumes have been used successfully in producing probiotic products with the minimum recommended viable probiotic numbers at the time of consumption. However, due to the exclusion of dairy, whether these food matrices can enhance the functional properties of probiotics such as gastrointestinal survival and immune-enhancing effects needs a thorough investigation. Hence, this review focuses on some of the popular non-dairy plant-based probiotic food products and their microbiological quality characteristics in terms of maintaining probiotic viability during product storage. Their gastrointestinal tolerance in these products, other functional properties, and product qualities have also been briefly discussed.

scholarly journals Identification of a CD4+ T cell-stimulating antigen of pathogenic bacteria by expression cloning.

1995 ◽  
Vol 182 (6) ◽  
pp. 1751-1757 ◽  
Author(s):  
S Sanderson ◽  
D J Campbell ◽  
N Shastri
Keyword(s):  
T Cells ◽  
Listeria Monocytogenes ◽  
T Cell ◽  
Mhc Class Ii ◽  
T Cell Activation ◽  
Pathogenic Bacteria ◽  
Genomic Library ◽  
Class Ii ◽  
Cd4 T Cell ◽  
Expression Cloning

Identifying the immunogenic proteins that elicit pathogen-specific T cell responses is key to rational vaccine design. While several approaches have succeeded in identifying major histocompatibility complex (MHC) class I bound peptides that stimulate CD8+ T cells, these approaches have been difficult to extend to peptides presented by MHC class II molecules that stimulate CD4+ T cells. We describe here a novel strategy for identifying CD4+ T cell-stimulating antigen genes. Using Listeria monocytogenes-specific, lacZ-inducible T cells as single-cell probes, we screened a Listeria monocytogenes genomic library as recombinant Escherichia coli that were fed to macrophages. The antigen gene was isolated from the E. coli clone that, when ingested by the macrophages, allowed generation of the appropriate peptide/MHC class II complex and T cell activation. We show that the antigenic peptide is derived from a previously unknown listeria gene product with characteristics of a membrane-bound protein.

Listeria monocytogenes: silage, sandwiches and science

2005 ◽  
Vol 6 (2) ◽  
pp. 211-217 ◽  
Author(s):  
Charles J. Czuprynski
Keyword(s):  
Listeria Monocytogenes ◽  
Murine Model ◽  
Pathogenic Bacteria ◽  
Model Organism ◽  
Intracellular Pathogen ◽  
Innate And Adaptive Immunity ◽  
Potential Vector ◽  
Broad Array ◽  
Common Framework ◽  
Substantial Risk

AbstractListeria monocytogenesis amongst the most intriguing and well studied of the pathogenic bacteria. However, the understanding and perspective one has ofL. monocytogenesdepends to a large extent on the microbiological issues with which one is faced as a part of your professional duties. The focus of the veterinary clinician or investigator is likely to be foremost on the neurologic (circling disease) and reproductive diseasesL. monocytogenescauses. To the food microbiologist, the principal concern is to prevent introduction ofL. monocytogenesinto food products, or to identify its presence and prevent its multiplication to numbers of organisms that are likely to pose a substantial risk to humans who ingest the product. To the cellular immunologist, listeriosis represents a robust murine model that helped to elucidate many important concepts in innate and adaptive immunity, andL. monocytogenesis a potential vector for delivery of novel vaccines. To the student of molecular pathogenesis,L. monocytogenesis a powerful and well-characterized model organism for studying the cellular microbiology of an intracellular pathogen. In this brief overview, I will attempt to highlight some of the classical observations, and contemporary insights, onL. monocytogenesand listeriosis, and integrate these perspectives into a common framework. By so doing, I hope to provide those with one perspective on listeriosis with an appreciation of the broad array of problems and issues faced by those who focus on some other aspect ofL. monocytogenesand its pathogenesis.

Highly sensitive conductometric biosensors for total lactate, d- and l-lactate determination in dairy products

2013 ◽  
Vol 179 ◽  
pp. 232-239 ◽  
Author(s):  
Thanh Thuy Nguyen-Boisse ◽  
Joelle Saulnier ◽  
Nicole Jaffrezic-Renault ◽  
Florence Lagarde
Keyword(s):  
Dairy Products ◽  
Highly Sensitive

scholarly journals A Rapid and Sensitive Europium Nanoparticle-Based Lateral Flow Immunoassay Combined with Recombinase Polymerase Amplification for Simultaneous Detection of Three Food-Borne Pathogens

2021 ◽  
Vol 18 (9) ◽  
pp. 4574
Author(s):  
Kai Chen ◽  
Biao Ma ◽  
Jiali Li ◽  
Erjing Chen ◽  
Ying Xu ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Vibrio Parahaemolyticus ◽  
Pathogenic Bacteria ◽  
Simultaneous Detection ◽  
Lateral Flow ◽  
Recombinase Polymerase Amplification ◽  
Quantitative Detection ◽  
Bacterial Strains ◽  
Food Borne Pathogens ◽  
Food Borne

Food-borne pathogens have become an important public threat to human health. There are many kinds of pathogenic bacteria in food consumed daily. A rapid and sensitive testing method for multiple food-borne pathogens is essential. Europium nanoparticles (EuNPs) are used as fluorescent probes in lateral flow immunoassays (LFIAs) to improve sensitivity. Here, recombinase polymerase amplification (RPA) combined with fluorescent LFIA was established for the simultaneous and quantitative detection of Listeria monocytogenes, Vibrio parahaemolyticus, and Escherichia coliO157:H7. In this work, the entire experimental process could be completed in 20 min at 37 °C. The limits of detection (LODs) of EuNP-based LFIA–RPA were 9.0 colony-forming units (CFU)/mL for Listeria monocytogenes, 7.0 CFU/mL for Vibrio parahaemolyticus, and 4.0 CFU/mL for Escherichia coliO157:H7. No cross-reaction could be observed in 22 bacterial strains. The fluorescent LFIA–RPA assay exhibits high sensitivity and good specificity. Moreover, the average recovery of the three food-borne pathogens spiked in food samples was 90.9–114.2%. The experiments indicate the accuracy and reliability of the multiple fluorescent test strips. Our developed EuNP-based LFIA–RPA assay is a promising analytical tool for the rapid and simultaneous detection of multiple low concentrations of food-borne pathogens.

Electrochemical biosensor for detection of pathogenic bacteria based on dual signal amplification of Cu3(PO4)2-mediated click chemistry and DNAzyme

The Analyst ◽  
2021 ◽  
Author(s):  
Hongguo Wei ◽  
Jiayu Wan ◽  
Shengjun Bu ◽  
Wenguang Zhang ◽  
Ma Li ◽  
...  
Keyword(s):  
Click Chemistry ◽  
Magnetic Separation ◽  
Concanavalin A ◽  
Signal Amplification ◽  
Pathogenic Bacteria ◽  
Electrochemical Biosensor ◽  
Inorganic Hybrid ◽  
Highly Sensitive ◽  
Antibody Conjugates ◽  
Dual Signal Amplification

A novel electrochemical biosensor for detecting pathogenic bacteria was designed based on specific magnetic separation and highly sensitive click chemistry. Instead of enzyme-antibody conjugates, organic-inorganic hybrid nanoflowers (Concanavalin A (Con...

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