scholarly journals Prevalence of Listeria monocytogenes and Salmonella spp. in Different Ready to Eat Foods from Large Retailers and Canteens over a 2-Year Period in Northern Italy

2021 ◽  
Vol 18 (20) ◽  
pp. 10568
Author(s):  
Marta Castrica ◽  
Egon Andoni ◽  
India Intraina ◽  
Giulio Curone ◽  
Emma Copelotti ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Significant Contribution ◽  
Food Samples ◽  
Northern Italy ◽  
Salmonella Spp ◽  
Preparation Methods ◽  
Group A ◽  
Fully Cooked ◽  
Cooked Food ◽  
Group B

This study aims to give an overview of the prevalence of Listeria monocytogenes and Salmonella spp. in 9727 samples (2996 for L. monocytogenes and 6731 for Salmonella spp.) from different categories of ready-to-eat (RTE) foods, collected over 2 years from 28 large retailers and 148 canteens in the regions of northern Italy. The RTE samples were classified into two groups according to the preparation methods: (i) multi-ingredient preparations consisting of fully cooked food ready for immediate consumption, or with minimal further handling before consumption (Group A), and (ii) multi-ingredient preparations consisting of cooked and uncooked food, or preparations consisting of only raw ingredients (Group B). L. monocytogenes and Salmonella spp. were investigated in both of these categories. The overall prevalence of L. monocytogenes and Salmonella spp. was 0.13% and 0.07%, respectively. More specifically, L. monocytogenes was found in 0.04% of 2442 analysed RTE food samples belonging to group A and in 0.54% of 554 samples belonging to group B. Furthermore, 0.03% of 5367 RTE food samples from group A and 0.21% of 1364 samples from group B tested positive for Salmonella spp. In conclusion, the results obtained in this study can provide a significant contribution to L. monocytogenes and Salmonella spp. risk analysis in RTE foods.

Microbiological Quality and Safety of Ready-To-Eat Cooked Foods from a Centralized School Kitchen in Argentina

2002 ◽  
Vol 65 (4) ◽  
pp. 636-642 ◽  
Author(s):  
M. A. TESSI ◽  
E. E. ARÍNGOLI ◽  
M. E. PIROVANI ◽  
A. Z. VINCENZINI ◽  
N. G. SABBAG ◽  
...  
Keyword(s):  
Foodborne Pathogens ◽  
Sensory Quality ◽  
Microbiological Quality ◽  
Food Samples ◽  
Food Groups ◽  
Salmonella Spp ◽  
Temperature Group ◽  
Group A ◽  
Cooked Food ◽  
Group B

The purpose of this study was to evaluate the microbiological and sensory quality as well as the safety of ready-to-eat (RTE) cooked foods prepared in and distributed from a centralized kitchen to schools in Argentina. A total of 101 cooked food samples delivered as hot RTE cooked foods (group A) and as RTE cooked foods at room temperature (group B) and 140 surface swab environment samples were collected from February to November 1999. Petrifilm plates were used for aerobic (PAC), coliform (PCC), and Escherichia coli (PEC) counts. Standard methods were used to determine Enterobacteriaceae (EntC) and thermotolerant coliform counts (TCC). Samples were also tested for the presence of Salmonella spp., Staphylococcus aureus, Bacillus cereus, and Clostridium perfringens. Food temperatures just before samples were put into containers ranged from 80 to 98°C and from 28 to 32°C for group A and group B, respectively. For group A food samples, PAC ranged from 1.04 to 3.50 log CFU/g, and PCC, PEC, TCC, and EntC were not detected. For group B food samples, PAC ranged from 3.63 to 6.48 log CFU/g, PCC ranged from 1.90 to 5.36 log CFU/g, TCC ranged from 1.30 to 3.95 log CFU/g, and EntC ranged from 3.60 to 5.46 log CFU/g. Of the foodborne pathogens, only B. cereus was isolated (63.4% of samples) in both food groups (<4 log CFU/g). The microbiological and sensory quality and the safety of group A foods were satisfactory. Large numbers of PAC and EntC detected in group B foods show that better control is needed to avoid potential foodborne diseases.

Combination of Immunomagnetic Separation and Polymerase Chain Reaction for the Simultaneous Detection of Listeria monocytogenes and Salmonella spp. in Food Samples

2001 ◽  
Vol 64 (11) ◽  
pp. 1744-1750 ◽  
Author(s):  
HSIEN-YEE HSIH ◽  
HAU-YANG TSEN
Keyword(s):  
Polymerase Chain Reaction ◽  
Listeria Monocytogenes ◽  
Simultaneous Detection ◽  
Meat Products ◽  
Immunomagnetic Separation ◽  
Food Samples ◽  
Chain Reaction ◽  
Salmonella Spp ◽  
Pcr Method ◽  
Polymerase Chain

A method that combined the immunomagnetic separation (IMS) technique and the multiplex polymerase chain reaction (PCR) method (i.e., the IMS-mPCR method) was developed for simultaneous detection of Listeria monocytogenes and Salmonella spp. in food samples. When only the multiplex PCR method was used, it was found that if cell numbers of each of the two target organisms (L. monocytogenes and Salmonella spp.) were above the detection limit, but differed by more than 2 logs—e.g., n × 107 to n × 104 or n × 106 to n × 103—the organism presenting the lower numbers might go undetected. Following the enrichment step with universal preenrichment (UP) broth, if an IMS method using equal quantities of anti-Listeria and anti-Salmonella immunomagnetic beads was performed prior to PCR, both pathogens could be detected unambiguously. Such results could be obtained for target organisms in food samples, such as milk, dairy, and meat products, if similar enrichment and IMS steps were performed prior to PCR.

scholarly journals Genotypic versus phenotypic methods in the detection of Listeria monocytogenes prosthetic joint infection

2009 ◽  
Vol 58 (6) ◽  
pp. 829-831 ◽  
Author(s):  
Barbora Žaloudíková ◽  
Martin Kelbl ◽  
Libor Paša ◽  
Tomáš Freiberger
Keyword(s):  
Listeria Monocytogenes ◽  
Prosthetic Joint Infection ◽  
Pathogen Detection ◽  
Joint Infection ◽  
Group B Streptococci ◽  
Prosthetic Joint ◽  
Routine Clinical Setting ◽  
Group A ◽  
Phenotypic Methods ◽  
Group B

A rare case of a severe prosthetic joint infection in a 71-year-old immunocompetent woman is presented. Listeria monocytogenes was identified in two consecutive samples using broad-range PCR and sequencing, whereas cultivation remained negative for the first sample and streptococci of a non-group A streptococci, non-group B streptococci type were detected for the second one. This report demonstrates that the phenotypic approach may lead to misidentification of L. monocytogenes in a routine clinical setting. Molecular methods of pathogen detection might be useful when a rare and/or unexpected micro-organism is present or the sample is collected during antibiotic treatment.

scholarly journals Definition of Genetically Distinct Attenuation Mechanisms in Naturally Virulence-Attenuated Listeria monocytogenes by Comparative Cell Culture and Molecular Characterization

2005 ◽  
Vol 71 (7) ◽  
pp. 3900-3910 ◽  
Author(s):  
Angela Roberts ◽  
Yvonne Chan ◽  
Martin Wiedmann
Keyword(s):  
Cell Culture ◽  
Listeria Monocytogenes ◽  
Hemolytic Activity ◽  
Molecular Techniques ◽  
Listeriolysin O ◽  
Virulence Attenuation ◽  
Genetic Mechanisms ◽  
Group A ◽  
Group B ◽  
Group D

ABSTRACT Listeria monocytogenes is a foodborne pathogen able to cause serious disease in humans and animals. Not all isolates are equally pathogenic, however, and several isolates have been characterized as naturally virulence attenuated. We sought to identify the genetic basis of natural virulence attenuation using cell culture assays and molecular techniques. By comparing the phenotypes of naturally virulence-attenuated isolates to those of defined virulence gene mutants in plaque, cytotoxicity, and hemolysis assays and by characterizing selected virulence genes and their expression using DNA sequencing and TaqMan reverse transcriptase PCR, we classified virulence-attenuated isolates into four categories. Both group A and group B isolates were noncytotoxic and nonhemolytic; however, group A isolates underexpressed listeriolysin O (LLO, encoded by hlyA), while group B isolates produced LLO proteins that were inactive. The single isolate in group C was fully cytotoxic, had higher than wild-type hemolytic activity, and was, therefore, likely virulence attenuated due to overexpression of LLO. Group D isolates were characterized by normal cytotoxicity, hemolytic activity, and hlyA expression but had reduced intracellular growth. The genetic mechanisms causing virulence-attenuated phenotypes among the group D isolates could not be determined definitively but may involve defects in the expression of actA or the function of the ActA protein. Our results show (i) that the combination of cell culture assays and molecular techniques used in this study allows for identification and characterization of naturally virulence-attenuated isolates and (ii) that multiple distinct genetic mechanisms are responsible for natural virulence attenuation in L. monocytogenes.

scholarly journals Treatment of enteric fever with pefloxacin for 7 days versus 5 days: a randomized clinical trial.

1996 ◽  
Vol 40 (12) ◽  
pp. 2898-2900 ◽  
Author(s):  
S Unal ◽  
M Hayran ◽  
S Tuncer ◽  
D Gür ◽  
O Uzun ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Clinical Cure ◽  
Enteric Fever ◽  
Day Treatment ◽  
Salmonella Typhi ◽  
Bacterial Eradication ◽  
Salmonella Spp ◽  
Group A ◽  
Paratyphi B ◽  
Group B

In this prospective study of enteric fever, 22 patients received 400 mg of pefloxacin twice daily for 5 days (group A) and 24 received 400 mg of pefloxacin twice daily for 7 days (group B). Causative microorganisms were Salmonella typhi (8 in group A, 11 in group B) and Salmonella paratyphi B (14 in group A, 13 in group B). The clinical cure and bacterial eradication rates were 96% (21 of 22) in group A and 100% in group B. In conclusion, 5-day oral administration of pefloxacin was as effective as 7-day treatment of enteric fever caused by Salmonella spp.

FoodSimplex as a Mean to Improve Portuguese Restaurants’ Goods Manufacturing Practices - Audit and Microbial Assessment

2020 ◽  
Vol 16 (9) ◽  
pp. 1449-1458
Author(s):  
Ana L. Baltazar ◽  
Ana Ferreira ◽  
Lara Manyes ◽  
Jordi Mañes
Keyword(s):  
Listeria Monocytogenes ◽  
Food Safety ◽  
Control Point ◽  
Food Samples ◽  
P Value ◽  
Salmonella Spp ◽  
E Coli ◽  
Critical Control Point ◽  
Audit Data ◽  
Coagulase Positive Staphylococci

Background: The consumption of meals at resturants has increased mass catering establishments. Such food services may present several risk factors for foodborne diseases, which have a substantial negative impact on public health. The smallest business with no technical or financial support struggles to comply with food safety European Regulation. The aim of this four years study was to assess Good Manufacture Practices (GMP) in Portuguese restaurants applying a designed food safety methodology, FoodSimplex, through audit data to determine good manufacture practices, and microbiological sampling of the meals before and after its implementation, by food groups according to their risk. Methods: FoodSimplex is a combination of four stages methodology, based on Hazards Analysis and Critical Control Point (HACCP), combined with technical-functional and food safety audits, with pretested checklist, training and microbial analysis (Mesophylic bacteria, Listeria monocytogenes, E. coli, Coagulase-positive staphylococci and Salmonella spp) of the meals served. Results: Results of the food safety audit for GMP parameters showed a general improvement with 80% compliance with the checklist subitems. The ready-to-eat food samples presented, regarding the total mesophilic aerobes count, a statistical significant change to acceptable and satisfactory condition (p-value= 0.029). 100% compliance, with acceptable and satisfactory results was observed for Listeria monocytogenes (p-value= 0.180) and for E. coli, coagulase-positive Staphylococci and Salmonella spp., all the food samples presented satisfactory results in the study (100%). Conclusion: At the end of the investigation period, a decrease in bacterial populations in food samples was observed with an improvement of the GMP audit data which indicated that the FoodSimplex methodology improved the food safety status of these establishments.

Multiplex Real-time PCR for the Simultaneous Detection of Salmonella spp. and Listeria monocytogenes in Food Samples

2010 ◽  
Vol 4 (2) ◽  
pp. 131-138 ◽  
Author(s):  
Olaya Ruiz-Rueda ◽  
Marçal Soler ◽  
Laia Calvó ◽  
Jesús L. García-Gil
Keyword(s):  
Listeria Monocytogenes ◽  
Real Time ◽  
Real Time Pcr ◽  
Simultaneous Detection ◽  
Food Samples ◽  
Salmonella Spp

An ultrastructural study of sertoli cells in two geographically isolated populations of Aphanius dispar

1992 ◽  
Vol 50 (1) ◽  
pp. 548-549
Author(s):  
Taber A. Ba-Omar ◽  
Philip F. Prentis
Keyword(s):  
Ultrastructural Level ◽  
Uranyl Acetate ◽  
Freshwater Teleost ◽  
Isolated Populations ◽  
En Bloc ◽  
The North ◽  
Group A ◽  
Ultrathin Sections ◽  
Group B ◽  
Geographically Isolated

We have recently carried out a study of spermiogenic differentiation in two geographically isolated populations of Aphanius dispar (freshwater teleost), with a view to ascertaining variation at the ultrastructural level. The sampling areas were the Jebel Al Akhdar in the north (Group A) and the Dhofar region (Group B) in the south. Specimens from each group were collected, the testes removed, fixed in Karnovsky solution, post fixed in OsO, en bloc stained with uranyl acetate and then routinely processed to Agar 100 resin, semi and ultrathin sections were prepared for study.

Comparison of one-year prognosis of patients classified as chronic critical lower limb ischaemia according to TASC II or European consensus definition in the COPART cohort

VASA ◽  
2015 ◽  
Vol 44 (3) ◽  
pp. 0220-0228 ◽  
Author(s):  
Marion Vircoulon ◽  
Carine Boulon ◽  
Ileana Desormais ◽  
Philippe Lacroix ◽  
Victor Aboyans ◽  
...  
Keyword(s):  
Medical Treatment ◽  
Critical Limb Ischaemia ◽  
Limb Ischaemia ◽  
Medical Group ◽  
Consensus Definition ◽  
Transcutaneous Oxygen ◽  
European Consensus ◽  
Group A ◽  
One Year ◽  
Group B

Background: We compared one-year amputation and survival rates in patients fulfilling 1991 European consensus critical limb ischaemia (CLI) definition to those clas, sified as CLI by TASC II but not European consensus (EC) definition. Patients and methods: Patients were selected from the COPART cohort of hospitalized patients with peripheral occlusive arterial disease suffering from lower extremity rest pain or ulcer and who completed one-year follow-up. Ankle and toe systolic pressures and transcutaneous oxygen pressure were measured. The patients were classified into two groups: those who could benefit from revascularization and those who could not (medical group). Within these groups, patients were separated into those who had CLI according to the European consensus definition (EC + TASC II: group A if revascularization, group C if medical treatment) and those who had no CLI by the European definition but who had CLI according to the TASC II definition (TASC: group B if revascularization and D if medical treatment). Results: 471 patients were included in the study (236 in the surgical group, 235 in the medical group). There was no difference according to the CLI definition for survival or cardiovascular event-free survival. However, major amputations were more frequent in group A than in group B (25 vs 12 %, p = 0.046) and in group C than in group D (38 vs 20 %, p = 0.004). Conclusions: Major amputation is twice as frequent in patients with CLI according to the historical European consensus definition than in those classified to the TASC II definition but not the EC. Caution is required when comparing results of recent series to historical controls. The TASC II definition of CLI is too wide to compare patients from clinical trials so we suggest separating these patients into two different stages: permanent (TASC II but not EC definition) and critical ischaemia (TASC II and EC definition).

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