OCCURRENCE OF LISTERIA MONOCYTOGENES IN READY TO EAT FOOD SAMPLES COLLECTED BY LOMBARDY REGION HEALTH AUTHORITIES IN 2009-2010

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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Optimization of a Viability PCR Method for the Detection of Listeria monocytogenes in Food Samples

Current Microbiology ◽

10.1007/s00284-018-1448-6 ◽

2018 ◽

Vol 75 (6) ◽

pp. 779-785 ◽

Cited By ~ 2

Author(s):

Gemma Agustí ◽

Mariana Fittipaldi ◽

Francesc Codony

Keyword(s):

Listeria Monocytogenes ◽

Food Samples ◽

Pcr Method

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Listeriolysin O-Based Latex Agglutination Test for the Rapid Detection of Listeria monocytogenes in Foods

Journal of Food Protection ◽

10.4315/0362-028x-60.9.1038 ◽

1997 ◽

Vol 60 (9) ◽

pp. 1038-1040 ◽

Cited By ~ 9

Author(s):

GHASSAN M. MATAR ◽

PEGGY S. HAYES ◽

WILLIAM F. BIBB ◽

BALA SWAMINATHAN

Keyword(s):

Monoclonal Antibody ◽

Listeria Monocytogenes ◽

Rapid Detection ◽

Rapid Test ◽

Food Samples ◽

Cross Reactivity ◽

Latex Agglutination ◽

Listeriolysin O ◽

Agglutination Assay ◽

Latex Beads

A latex agglutination-based test for the rapid detection of Listeria monocytogenes in foods was developed. An antilisteriolysin O (LLO) monoclonal antibody (HID5E12D7; IgG2b) covalently bound to polystyrene amidine-modified latex beads was used in a slide agglutination assay. The latex reagent detected 0.1 ng/ml of LLO in phosphate-buffered saline plus bovine serum albumin. It reacted with culture supernatants of L. monocytogenes but not with other Listeria species or Streptococcus groups A through G. The listeriolysin O latex agglutination assay (LLOLAT) was applied to 24-h and 48-h USDA primary enrichment cultures of 208 food samples obtained from refrigerators of listeriosis patients enrolled in a study to determine the role of foods in sporadic listeriosis. Of 19 samples positive by cultural techniques, 17 were positive by the LLOLAT. Cultures with low (<0.3 CFU/g) levels of L. monocytogenes were positive in the LLOLAT. No cross-reactivity occurred when using a heterogeneous monoclonal antibody. The LLOLAT is a sensitive, specific and rapid test and may be useful for screening foods for L. monocytogenes.

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Prevalence and Numbers of Listeria monocytogenes in Various Ready-to-Eat Foods over a 5-Year Period in Estonia

Journal of Food Protection ◽

10.4315/0362-028x.jfp-18-383 ◽

2019 ◽

Vol 82 (4) ◽

pp. 597-604 ◽

Cited By ~ 4

Author(s):

JULIA KOSKAR ◽

TOOMAS KRAMARENKO ◽

KADRIN MEREMÄE ◽

MAIU KUNINGAS ◽

JELENA SÕGEL ◽

...

Keyword(s):

Listeria Monocytogenes ◽

Risk Groups ◽

Food Samples ◽

Safety Criterion ◽

Fish Products ◽

Product Categories ◽

Salted Fish ◽

Smoked Fish ◽

High Prevalence ◽

Fish Product

ABSTRACT The prevalence and numbers of Listeria monocytogenes in various categories of ready-to-eat (RTE) food products taken from retail outlets and food industries over a 5-year period are presented. A total of 30,016 RTE food samples were analyzed for L. monocytogenes prevalence, and 3.6% were found to be positive. The highest prevalence was found for RTE fish and fish products (11.6%), especially for lightly salted and cold-smoked fish products. The overall prevalence of L. monocytogenes in other food categories was low, within the range of 0 to 3.9%. In addition, 14,342 RTE food samples were analyzed to determine the numbers of L. monocytogenes. A food safety criterion of 100 CFU/g was exceeded for 0.3% of RTE food samples. Samples most often exceeding the legal safety limit were from the RTE salted and cold-smoked fish product categories. High prevalence, 28.6 and 26.5%, respectively, and high numbers of L. monocytogenes among salted fish and cold-smoked fish products indicate a risk of listeriosis, especially for susceptible risk groups. The results of the current study can be used at both the national and the international levels to update the perception of the L. monocytogenes risk deriving from RTE foods. HIGHLIGHTS

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A Study to Evaluate the Need for Comminution in the Preparation of Food Materials for Testing of Listeria monocytogenes, Staphylococcus Species, and Generic Escherichia coli

Journal of AOAC International ◽

10.1093/jaoacint/qsaa074 ◽

2020 ◽

Vol 103 (6) ◽

pp. 1639-1645

Author(s):

Patricia Hanson ◽

Nicole Mitchell ◽

S Brian Caudle ◽

Lyndsey Caulkins ◽

Cameron Owens ◽

...

Keyword(s):

Escherichia Coli ◽

Listeria Monocytogenes ◽

Sampling Method ◽

Sampling Error ◽

Food Samples ◽

Test Portion ◽

Target Analytes ◽

Wide Range ◽

Current Sampling ◽

Selection Of

Abstract Background Comminution reduces the sampling error arising from distributional heterogeneity of the target contaminant/target analyte in the material, facilitating the selection of a more representative test portion. A laboratory sampling method incorporating comminution prior to selection of the test portion (Sampling Method B) was compared to current sampling methods that used no comminution step (Sampling Method A). Objective This required the development of an efficient process for comminution of food samples prior to removal of the test portion for the detection and isolation of Listeria monocytogenes and the enumeration of Staphylococcus species and Escherichia coli. Method From December 2016 to December 2017, 2742 tests were conducted on 778 unique food samples. For all food samples, a test portion (TPA) was first removed using Sampling Method A, and then the remainder of the material was comminuted and a second test portion (TPB) was removed using Sampling Method B and tested alongside the first portion. Results Across all food matrices and microbial targets, 17 additional targets were detected using only Sampling Method B, and positive detections of target analytes increased by 77% using Sampling Method B from the test portions taken using Sampling Method A. Conclusion Utilizing a sample preparation method that includes a comminution step resulted in an increased number of pathogen detections. Highlights The introduction of a comminution step in the preparation of food samples for detection of three common microbial contaminants resulted in an increase in the rate of detection of natural contaminates in a variety of ready to eat foods. An efficient aseptic process for commutation that can be adapted to a wide range of laboratory settings was identified.

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Recombinase Polymerase Amplification-Based Assay for Rapid Detection of Listeria monocytogenes in Food Samples

Food Analytical Methods ◽

10.1007/s12161-016-0775-0 ◽

2016 ◽

Vol 10 (6) ◽

pp. 1972-1981 ◽

Cited By ~ 20

Author(s):

Weifang Gao ◽

Hailong Huang ◽

Yan Zhang ◽

Peng Zhu ◽

Xiaojun Yan ◽

...

Keyword(s):

Listeria Monocytogenes ◽

Rapid Detection ◽

Food Samples ◽

Recombinase Polymerase Amplification

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A new method for rapid detection of Listeria monocytogenes in food

Czech Journal of Food Sciences ◽

10.17221/8319-cjfs ◽

2000 ◽

Vol 18 (No. 3) ◽

pp. 103-109 ◽

Cited By ~ 3

Author(s):

K. Zdeňková ◽

K. Demnerová ◽

G. Jeníková ◽

J. Pazlarová

Keyword(s):

Listeria Monocytogenes ◽

Pcr Primers ◽

Immunomagnetic Separation ◽

Food Samples ◽

Special Importance ◽

Ground Meat ◽

Specific Detection ◽

Gene Encoding ◽

Pcr Method

Listeria monocytogenes represents serious danger for human health. Thus detection of this pathogen in food, which represents its main means of entry into the organism, is a topic of special importance. The original classic methods for the determination of Listeria monocytogenes are in general laborious and time-consuming procedures. In order to address this issue we developed a new rapid method for specific detection of Listeria monocytogenes in food samples. The method consists of three steps: i) enrichment of food microflora (16 h), ii) selective isolation of Listeria sp. exploiting immunomagnetic separation (2–3 h) followed by iii) precise identification of Listeria sp. and Listeria monocytogenes using duplex PCR. PCR primers specific to part of 16S rRNA were used in order to identify the members of Listeria genus. The specific identification of Listeria monocytogenes was accomplished exploiting a pair of primers specific to gene encoding invasion-associated protein – iap (4–5 h). Amplification products, 1003 bp and 593 bp respectively, were separated by electrophoresis and visualized by UV detection. The optimized IMS-PCR method was used to test the presence of Listeria sp. and Listeria monocytogenes in food samples (ground meat, low-fat milk and cheese [olomoucké tvarůžky]). A comparison of the efficiency of the bacteria enrichment step by IMS and centrifugation was also performed. The analysis time including enrichment is less than 24 h. The detection limit for Listeria monocytogenes was found between 101–102 cfu per 25 g of food sample.

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Preparation of Fluorescent Molecularly Imprinted Polymers via Pickering Emulsion Interfaces and the Application for Visual Sensing Analysis of Listeria Monocytogenes

Polymers ◽

10.3390/polym11060984 ◽

2019 ◽

Vol 11 (6) ◽

pp. 984 ◽

Cited By ~ 11

Author(s):

Xiaolei Zhao ◽

Yan Cui ◽

Junping Wang ◽

Junying Wang

Keyword(s):

Listeria Monocytogenes ◽

Sample Pretreatment ◽

Spherical Shape ◽

Pickering Emulsion ◽

Food Samples ◽

Water Soluble ◽

Water Emulsion ◽

Molecularly Imprinted ◽

Oil In Water ◽

Oil In Water Emulsion

In this work, a novel molecularly imprinted polymer (MIP) with water-soluble CdTe quantum dots (QDs) was synthesized by oil-in-water Pickering emulsion polymerization using whole Listeria monocytogenes as the template. Listeria monocytogenes was first treated by acryloyl-functionalized chitosan with QDs to form a bacteria–chitosan network as the water phase. This was then stabilized in an oil-in-water emulsion comprising a cross-linker, monomer, and initiator, causing recognition sites on the surface of microspheres embedded with CdTe QDs. The resulting MIP microspheres enabled selective capture of the target bacteria via recognition cavities. The target bacteria Listeria monocytogenes was detected. Scanning electron microscopy (SEM) characterization showed that the MIPs had a rough spherical shape. There was visual fluorescence detection via quenching in the presence of the target molecule, which offered qualitative detection of Listeria monocytogenes in milk and pork samples. The developed method simplified the analysis process and did not require any sample pretreatment. In addition, the fluorescence sensor provided an effective, fast, and convenient method for Listeria monocytogenes detection in food samples.

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Rapid detection of Listeria monocytogenes in raw milk and soft cheese by a redox potential measurement based method combined with real-time PCR

Acta Veterinaria Hungarica ◽

10.1556/avet.2014.013 ◽

2014 ◽

Vol 62 (3) ◽

pp. 304-316 ◽

Cited By ~ 1

Author(s):

Orsolya Erdősi ◽

Katalin Szakmár ◽

Olivér Reichart ◽

Zsuzsanna Szili ◽

Noémi László ◽

...

Keyword(s):

Listeria Monocytogenes ◽

Redox Potential ◽

Real Time ◽

Real Time Pcr ◽

Rapid Detection ◽

Raw Milk ◽

Food Samples ◽

Potential Measurement ◽

Effective Manner ◽

Soft Cheese

The incidence of outbreaks of foodborne listeriosis has indicated the need for a reliable and rapid detection of the microbe in different foodstuffs. A method combining redox potential measurement and real-time polymerase chain reaction (PCR) was developed to detectListeria monocytogenesin artificially contaminated raw milk and soft cheese. Food samples of 25 g or 25 ml were homogenised in 225 ml of Listeria Enrichment Broth (LEB) with Oxford supplement, and the redox potential measurement technique was applied. ForListeriaspecies the measuring time was maximum 34 h. The absence ofL. monocytogenescould reliably be proven by the redox potential measurement method, butListeria innocuaandBacillus subtiliscould not be differentiated fromL. monocytogeneson the basis of the redox curves. The presence ofL. monocytogeneshad to be confirmed by real-time PCR. The combination of these two methods proved to detect < 10 cfu/g ofL. monocytogenesin a cost- and time-effective manner. This method can potentially be used as an alternative to the standard nutrient method for the rapid detection ofL. monocytogenesin food.

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