scholarly journals Challenge Studies to Determine the Ability of Foods to Support the Growth of Listeria monocytogenes

Pathogens ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 80 ◽  
Author(s):  
Karen Hunt ◽  
Marjorie Blanc ◽  
Avelino Álvarez-Ordóñez ◽  
Kieran Jordan
Keyword(s):  
Listeria Monocytogenes ◽  
Shelf Life ◽  
Foodborne Pathogen ◽  
Bacterial Count ◽  
Total Bacterial Count ◽  
Reference Laboratory ◽  
Guidance Document ◽  
The European Union ◽  
European Union Reference Laboratory ◽  
Smoked Salmon

: Listeria monocytogenes is a foodborne pathogen that causes listeriosis, a relatively rare, but potentially fatal, disease, with a mortality rate of 20–30%. In general, European Regulations require the absence of L. monocytogenes in five samples of 25 g before the food has left the producer, but if the food has been demonstrated not to support the growth of L. monocytogenes, up to 100 cfu g-1 are allowed in the food (except for foods for infants or medical purposes) during its shelf-life under reasonably foreseeable storage conditions. It is important for food producers to determine if their food supports the growth of L. monocytogenes. The European Union Reference Laboratory for L. monocytogenes published a Technical Guidance document for conducting shelf-life studies on L. monocytogenes in ready-to-eat foods in June 2014. Primarily based on the EURL guidance document for conducting challenge studies, the ability of cheese (feta and soft goat’s milk cheese), cold-smoked salmon, coleslaw, and pork pate to support the growth of L. monocytogenes was determined using a starting inoculum of approximately 100 cfu g−1. The cheese and pork pate were incubated at 8 °C for 14 days; the smoked salmon was incubated at 6 °C for 5 days and 8°C for 9 days; and the coleslaw was incubated at 8 °C for 7 days and 12 °C for 14 days. The results showed that the smoked salmon and pork pate supported growth, while coleslaw and cheese did not. From this study, it is evident that there are factors in food other than pH, water activity, and total bacterial count (TBC) that can inhibit the ability of L. monocytogenes to grow in food.

scholarly journals Collection of Listeria monocytogenes Isolates from Milk, Dairy Products and Food Processing Environments in Slovakia for the Purposes of European Molecular Database

2017 ◽  
Vol 61 (1) ◽  
pp. 60-65
Author(s):  
Z. Kubicová ◽  
M. Filipová ◽  
J. Jurovčíková ◽  
L Cabanová
Keyword(s):  
Listeria Monocytogenes ◽  
Dairy Products ◽  
Food Chains ◽  
Reference Laboratory ◽  
The European Union ◽  
Comparison Analysis ◽  
European Union Reference Laboratory ◽  
And Control ◽  
Different Sources ◽  
Epidemiological Information

Abstract The molecular typing of Listeria monocytogenes isolates is an important tool for monitoring the spread of the strains in food chains, providing evidence for epidemiological investigations and for the detection of out-breaks. The demand of European typing data centralization, collection and sharing stimulated the generation of “EURL L. monocytogenes Database (EURL Lm DB)” in 2012 led by the European Union Reference Laboratory (EURL) for L. monocytogenes (ANSES Maisons-Alfort Laboratory for Food Safety, France) in close collaboration with Applied Maths. This database includes the typing results and epidemiological information on strains isolated from food, environmental or animal samples and it is in connection with human strains database TESSy (The European Surveillance System) led by the ECDC (European Centre for Disease Prevention and Control). In total 147 L. monocytogenes isolates were examined by PFGE (pulsed field gel electrophoresis) in 2014—2015 in VFI Dolny Kubin from different sources. Nearly half (68) of the 147 isolates in the national Slovak database came from milk or dairy products samples and the related manufacturing environment. In this work, 68 isolates associated with milk were selected and divided into 27 clusters (95 % similarity level) after combined comparison analysis (AscI and ApaI) by BioNumerics 6.6 software. Eight clusters included three or more similar PFGE profiles.

scholarly journals Foodborne Pathogen Assessment in Raw Milk Cheeses

2020 ◽  
Vol 2020 ◽  
pp. 1-5
Author(s):  
Nicola Costanzo ◽  
Carlotta Ceniti ◽  
Adriano Santoro ◽  
Maria Teresa Clausi ◽  
Francesco Casalinuovo
Keyword(s):  
Listeria Monocytogenes ◽  
Foodborne Pathogens ◽  
Foodborne Pathogen ◽  
Bacterial Count ◽  
Raw Milk ◽  
Good Manufacturing Practice ◽  
Staphylococcal Enterotoxin ◽  
Total Bacterial Count ◽  
E Coli ◽  
Coagulase Positive Staphylococci

General hygienic parameters and selected foodborne pathogens in raw milk cheeses at the retail level were evaluated. A total of 245 raw milk cheese samples were analysed for total bacterial count, Enterobacteriaceae, E. coli, Salmonella spp., Listeria monocytogenes, coagulase-positive Staphylococci, and staphylococcal enterotoxin. Results showed only 3 samples that were not compliant with European rules on staphylococcal enterotoxin, but coagulase-positive Staphylococci were evidenced in all samples tested. Salmonella spp. and Listeria monocytogenes were never detected whereas E. coli was evidenced in 20 samples. Results suggest a need for improvement of good manufacturing practice and milking operation.

scholarly journals A note on challenge trials to determine the growth of Listeria monocytogenes on mushrooms (Agaricus bisporus)

2015 ◽  
Vol 54 (2) ◽  
pp. 121-125 ◽  
Author(s):  
Dara Leong ◽  
Avelino Alvarez-Ordóñez ◽  
Kieran Jordan
Keyword(s):  
Listeria Monocytogenes ◽  
Agaricus Bisporus ◽  
Reference Laboratory ◽  
The European Union ◽  
European Union Reference Laboratory ◽  
Colony Forming Units ◽  
Challenge Tests ◽  
Micro Organisms ◽  
Growth Assessment ◽  
The Eu

AbstractIn the EU, food is considered safe with regard toListeria monocytogenesif the number of micro-organisms does not exceed 100 colony forming units (cfu)/g throughout its shelf-life. Therefore, it is important to determine if a food supports growth ofL. monocytogenes. Guidelines for conducting challenge tests for growth assessment ofL. monocytogeneson foods were published by the European Union Reference Laboratory (EURL) in 2014. The aim of this study was to use these guidelines to determine if refrigerated, fresh, whole, closed-cap, prepackaged mushrooms (Agaricus bisporus) support the growth ofL. monocytogenes. Three batches of mushrooms were artificially inoculated at approximately 100 cfu/g with a three-strain mix ofL. monocytogenesand incubated for 2 days at 8°C followed by 4 days at 12°C.L. monocytogenesnumbers were determined (in triplicate for each batch) on days 0, 2 and 6. Water activity, pH and total bacterial counts were also determined. There was no increase in the number ofL. monocytogenesabove the threshold of 0.5 log cfu/g in any of the replicates. In 8 of 9 replicates, the numbers decreased indicating thatA. bisporusdo not support the growth ofL. monocytogenes. As the EU regulations allow < 100 cfu/g if the food cannot support growth ofL. monocytogenes, the significance of this study is that mushrooms with < 100 cfu/g may be within the regulations and therefore, quantitative rather than qualitative determination may be required.

IMEP-115: Determination of Methylmercury in Seafood by Elemental Mercury Analysis: Collaborative Study

2014 ◽  
Vol 97 (2) ◽  
pp. 593-597 ◽  
Author(s):  
Fernando Cordeiro ◽  
Josep Calderón ◽  
Susana Gonçalves ◽  
Maria Helena Lourenço ◽  
Piotr Robouch ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Elemental Mercury ◽  
Reference Laboratory ◽  
The European Union ◽  
European Union Reference Laboratory ◽  
Test Items ◽  
Liquid Liquid Extraction ◽  
Mercury Analysis ◽  
Mercury Analyzer

Abstract A collaborative study IMEP-115 was organized by the European Union Reference Laboratory for Heavy Metals in Feed and Food (EURL-HM) to validate a method for the determination of methylmercury in seafood. The method was based on a liquid–liquid extraction with an organic solvent and with an aqueous cysteine solution. The final quantitation was done with an elemental mercury analyzer. Fifteen laboratories experienced in elemental mercury analyses, from 10 European countries, took part in the exercise. Five test items were selected to cover the concentration range from 0.013 to 5.12 mg/kg. All test items were reference materials certified for the methylmercury mass fraction: DOLT-4 (dogfish liver), TORT-2 (lobster hepatopancreas), SRM 2974a (mussel), SRM 1566b (oyster), and ERM CE-464 (tuna). Participants also received a bottle of ERM CE-463 (tuna) to test their analytical method before starting the collaborative study. Method validation showed adequate accuracy and acceptable precision for all test items, thus fitting its intended analytical purpose. The repeatability RSD ranged from 3.9 to 12.3%, while the reproducibility RSD ranged from 8.4 to 24.8%.

scholarly journals β-Phenylethylamine as a Natural Food Additive Shows Antimicrobial Activity against Listeria monocytogenes on Ready-to-Eat Foods

Foods ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1363 ◽  
Author(s):  
Francis Muchaamba ◽  
Roger Stephan ◽  
Taurai Tasara
Keyword(s):  
Listeria Monocytogenes ◽  
Foodborne Pathogen ◽  
Bactericidal Effect ◽  
Model Systems ◽  
Natural Food ◽  
Smoked Salmon ◽  
Growth Inhibitory ◽  
Good Manufacturing Practices ◽  
Agar Media

Listeria monocytogenes is an important foodborne pathogen and a major cause of death associated with bacterial foodborne infections. Control of L. monocytogenes on most ready-to-eat (RTE) foods remains a challenge. The potential use of β-phenylethylamine (PEA) as an organic antimicrobial against L. monocytogenes was evaluated in an effort to develop a new intervention for its control. Using a collection of 62 clinical and food-related isolates we determined the minimum inhibitory concentration (MIC) of PEA against L. monocytogenes in different broth and agar media. Bologna type sausage (lyoner) and smoked salmon were used as food model systems to validate the in vitro findings. PEA had a growth inhibitory and bactericidal effect against L. monocytogenes both in in vitro experiments as well as on lyoner and smoked salmon. The MIC’s ranged from 8 to 12.5 mg/mL. Furthermore, PEA also inhibited L. monocytogenes biofilm formation. Based on good manufacturing practices as a prerequisite, the application of PEA to RTE products might be an additional hurdle to limit L. monocytogenes growth thereby increasing food safety.

scholarly journals Estimation of the shelf-life of halloumi cheese using survival analysis

2012 ◽  
Vol 30 (No. 6) ◽  
pp. 512-519 ◽  
Author(s):  
R. Kamleh ◽  
I. Toufeili ◽  
R. Ajib ◽  
B. Kanso ◽  
J. Haddad
Keyword(s):  
Survival Analysis ◽  
Shelf Life ◽  
Anaerobic Bacteria ◽  
Titratable Acidity ◽  
Bacterial Count ◽  
Microbial Populations ◽  
Total Bacterial Count ◽  
Failure Index ◽  
Good Manufacturing Practices ◽  
Yeasts And Molds

Halloumi cheese blocks, packaged in vacuum polyamide/polyethylene laminate bags, were stored at 5, 15, and 25&deg;C. The changes in total bacterial count, lactic acid bacteria, total anaerobic bacteria, yeasts and molds, pH, and titratable acidity were monitored during the storage. The appearance of the packaged Halloumi cheese exhibited significant correlations with the counts of the different microbial populations inhabiting the cheese. The shelf-life of the stored Halloumi cheese was determined using survival analysis and considering consumer rejection as a failure index. The nominal shelf-lives of Halloumi cheese were 79.6, 37.8, and 2.6 days when stored at 5, 15, and 25&deg;C, respectively. The Q<sub>10</sub> values (shelf-life at T &deg;C/shelf-life at T + 10&deg;C) at 5&deg;C and 15&deg;C were 2.1 and 14.5, respectively. The increase in the counts of different microbial populations during storage highlights the need for adherence to good manufacturing practices and maintenance of low temperatures during the storage and distribution of the packaged Halloumi cheese.

Low Prevalence of Listeria monocytogenes in Foods from Italy

2007 ◽  
Vol 70 (6) ◽  
pp. 1507-1512 ◽  
Author(s):  
L. LATORRE ◽  
A. PARISI ◽  
R. FRACCALVIERI ◽  
G. NORMANNO ◽  
M. C. NARDELLA LA PORTA ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Foodborne Pathogen ◽  
Poultry Meat ◽  
Animal Origin ◽  
Smoked Salmon ◽  
Hygienic Measures ◽  
Seafood Products ◽  
Common Serotypes ◽  
Meat Samples ◽  
Low Prevalence

Listeria monocytogenes is an important foodborne pathogen that causes gastrointestinal disorders, and, especially in immunocompromised people, serious extraintestinal diseases, such as septicemia and meningitis, as well as abortion in pregnant women. Many foods, from both plant and animal origin, have been involved in listeriosis outbreaks. This article reports the results of a 12-year survey (1993 through 2004) on the presence of L. monocytogenes in several kinds of food marketed in Italy. Of 5,788 analyzed samples, 121 (2.1%) were contaminated with L. monocytogenes. The highest prevalence was found in smoked salmon (10.6%) and in poultry meat samples (8.5%) and the lowest in red meat (0.3%). L. monocytogenes was not found in 154 samples of fresh seafood products. Fifty-two isolates were also serotyped by the agglutination method. The most common serotypes detected in the 52 strains tested were 1/2a (36.5%), followed by 1/2c (32.8%), 1/2b (13.5%), 4b (11.5%), 3a (3.8%), and 3b (1.9%). The results of the present study showed low levels of L. monocytogenes in the analyzed samples. A total of 61.5% of the 52 L. monocytogenes strains analyzed belonged to serotypes 1/2a, 1/2b, and 4b, namely the serovars that are most commonly involved in extraintestinal human listeriosis outbreaks. In the ready-to-eat samples, these three serotypes were 40.0% (1/2a), 17.1% (1/2b), and 14.3% (4b). This finding highlights the need to implement strict hygienic measures during the production, distribution, and sale of foods to reduce the risk of foodborne listeriosis in humans to an acceptable level.

The proficiency testing program of the European Union Reference Laboratory for E. coli

2015 ◽  
Vol 20 (5) ◽  
pp. 381-385
Author(s):  
Clarissa Ferreri ◽  
Fabio Galati ◽  
Laura Grande ◽  
Antonella Maugliani ◽  
Valeria Michelacci ◽  
...  
Keyword(s):  
European Union ◽  
Proficiency Testing ◽  
Reference Laboratory ◽  
The European Union ◽  
Testing Program ◽  
European Union Reference Laboratory ◽  
E Coli

Proficiency testing carried out by the European Union Reference Laboratory for Parasites

2015 ◽  
Vol 20 (4) ◽  
pp. 311-317 ◽  
Author(s):  
Patrizia Rossi ◽  
Gianluca Marucci ◽  
Marco Lalle ◽  
Adriano Casulli ◽  
Alessia Possenti ◽  
...  
Keyword(s):  
European Union ◽  
Proficiency Testing ◽  
Reference Laboratory ◽  
The European Union ◽  
European Union Reference Laboratory
Sign in / Sign up

Export Citation Format

Share Document