scholarly journals Thermal inactivation and growth potential of Listeria monocytogenes in smoked tench

2016 ◽  
Vol 5 (3) ◽  
Author(s):  
Raffaella Branciari ◽  
Andrea Valiani ◽  
Raffaella Franceschini ◽  
David Ranucci ◽  
Alessia Lupattelli ◽  
...  
Keyword(s):  
Experimental Study ◽  
Listeria Monocytogenes ◽  
Thermal Inactivation ◽  
Challenge Test ◽  
Listeria Innocua ◽  
Growth Potential ◽  
Post Processing ◽  
Colony Forming Unit ◽  
Post Process ◽  
Hygiene Measures

An experimental study for the evaluation of <em>Listeria monocytogenes</em> inactivation during a hot smoking process in tench was performed using <em>Listeria innocua</em> strains. Furthermore, the survival of <em>L. monocytogenes</em> in smoked tench was determined after post-processing in contaminated samples, evaluating the growth potential during storage. <em>L. innocua</em> was not detected after the smoking process. In the challenge test, the growth potential of <em>L. monocytogenes</em> was 5.68 log colony forming unit g<sup>−1</sup>. The results showed that hot smoking at an inner temperature around 72°C is able to eliminate the microorganism. Nevertheless, the product is able to support the growth of the pathogen if post-process contamination occurs, as the food is suitable for <em>Listeria</em> multiplication. Product recontamination should be prevented by means of appropriate application of hygiene measures.

scholarly journals Growth Potential of Listeria monocytogenes in Three Different Salmon Products

Foods ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1048 ◽  
Author(s):  
Corinne Eicher ◽  
Andres Ruiz Subira ◽  
Sabrina Corti ◽  
Arnulf Meusburger ◽  
Roger Stephan ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Challenge Test ◽  
High Growth ◽  
Growth Potential ◽  
High Concentration ◽  
Food Borne ◽  
Smoked Salmon ◽  
Good Manufacturing Practices ◽  
Challenge Tests ◽  
Low Levels

Cold smoked salmon and sushi salmon have been implicated in outbreaks of listeriosis. We performed challenge tests and a durability study with Listeria monocytogenes on different salmon products to determine the growth potential of this important food-borne pathogen. Data from the challenge test showed a significant growth potential of L. monocytogenes on all of the tested salmon products, with faster growth in sushi salmon than in cold smoked salmon. In identical products that were naturally contaminated at low levels, the durability study did not confirm a high growth potential, possibly due to interactions with competing microflora. The injection of sodium lactate (NaL) at a high concentration (30%) into cold smoked salmon significantly reduced the growth potential of L. monocytogenes. In addition to good manufacturing practices, the injection of higher concentrations of NaL may therefore be a useful additional hurdle to prevent growth of L. monocytogenes to high numbers in the tested salmon products.

scholarly journals Challenge Test as Special Tool to Estimate the Dynamic of Listeria monocytogenes and Other Foodborne Pathogens

Foods ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 32
Author(s):  
Luigi Lanni ◽  
Valeria Morena ◽  
Adriana Scattareggia Marchese ◽  
Gessica Destro ◽  
Marcello Ferioli ◽  
...  
Keyword(s):  
European Union ◽  
Listeria Monocytogenes ◽  
Foodborne Pathogens ◽  
Challenge Test ◽  
Growth Potential ◽  
Economic Losses ◽  
Hospital Treatment ◽  
The European Union ◽  
Advantages And Disadvantages ◽  
Challenge Tests

Over 23 million cases of foodborne disease (FBD) occur in Europe each year, with over 4700 deaths. Outbreaks of FBD have a significant impact on our society due to the high economic losses they cause (hospital treatment of affected patients and destruction of contaminated food). Among its health objectives, the European Union has set itself the goal of reducing the incidence of the main FBDs, approving various regulations that codify requirements in order to produce food that is “safe” for human consumption. Among these rules, Regulation 2005/2073 establishes precise food safety criteria for foods that are judged to be most at risk of causing episodes of FBD. The food business operator (FBO) must know their food better and know how to estimate whether a food can support the growth of food pathogens or if they are able to hinder it during the food’s shelf life. It is becoming crucial for each FBO to schedule specific laboratory tests (challenge tests) to establish the growth potential of individual pathogens and their maximum growth rate. In 2008 the European Union published the guidelines for programming the challenge tests for Listeria monocytogenes in RTE foods. These guidelines were further implemented in 2014 and again in 2019. In June 2019 the UNI EN ISO 20976-1 was published, which contains indications for setting up and carrying out challenge tests for all foodborne pathogens in all foods. In this article, we compare the three official documents to highlight their common aspects and differences, highlighting the advantages and disadvantages that each of them offers for those who have to set up a challenge test for the various foodborne pathogens. Our conclusion is that the challenge test is today the most effective tool to estimate the dynamics and growth potential of pathogenic microorganisms in food, if it is designed and implemented in a scrupulous way. It is important to develop a rational experimental design for each challenge test, and for each food, and this requires professionals who are experts in this specific field of study and who must be properly trained.

scholarly journals Growth potential of Listeria monocytogenes in veal tartare

2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Simone Stella ◽  
Cristian Bernardi ◽  
Erica Tirloni
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Shelf Life ◽  
Challenge Test ◽  
Growth Potential ◽  
Daily Maximum ◽  
Initial Concentration ◽  
Spoilage Bacteria ◽  
Sampling Times

In the present study the growth potential of Listeria monocytogenes in veal tartare was evaluated. A challenge test was performed on three tartare batches at 8°C, aiming to evaluate the growth potential of the pathogen. The data indicated the absence of a significant growth (δ<0.5 log cfu/g) during the entire period. When considering intermediate sampling times, an increase of 0.56 log cfu/g was detected after five days of storage in one of the batches. Microflora of veal tartare was dominated by lactic acid bacteria, that increased gradually during the trial, reaching counts up to 7 Log CFU/g in two of the three batches considered. Spoilage bacteria were present (especially Pseudomonas spp., yeasts and Enterobacteriaceae) but in very low counts and with a limited increase during the period considered. Finally, daily maximum tolerable L. monocytogenes counts were calculated to highlight the maximum acceptable load to avoid the overcoming of the legal limit of 100 CFU/g: a total increase of 0.95 log cfu/g in 12 days of shelf-life was estimated, obtaining a “safety initial concentration” at t0 of 10 CFU/g of the pathogen.

scholarly journals Identifying suitableListeria innocuastrains as surrogates forListeria monocytogenesfor horticultural products

2019 ◽  
Author(s):  
Vathsala Mohan ◽  
Reginald Wibisono ◽  
Lana de Hoop ◽  
Graeme Summers ◽  
Graham C Fletcher
Keyword(s):  
Listeria Monocytogenes ◽  
Thermal Inactivation ◽  
Listeria Innocua ◽  
Peroxyacetic Acid ◽  
Safety Risks ◽  
Horticultural Products ◽  
Different Strains ◽  
The Individual ◽  
Uv C ◽  
Strain Dependent

AbstractWe conducted a laboratory-based study testing nineListeria innocuastrains independently and a cocktail of 11Listeria monocytogenesstrains. The aim was to identify suitableL. innocuastrain(s) to modelL. monocytogenesin inactivation experiments. Three separate inactivation procedures and a hurdle combination of the three were employed: thermal inactivation (55°C), UV-C irradiation (245 nm) and chemical sanitiser (Tsunami™ 100, a mixture of acetic acid, peroxyacetic acid and hydrogen peroxide). The responses were strain dependent in the case ofL. innocuawith different strains responding differently to different regimes.L. innocuaisolates generally responded differently to theL. monocytogenescocktail and had different responses among themselves. In the thermal inactivation treatment, inactivation of all strains including theL. monocytogenescocktail plateaued after 120 minutes. Chemical sanitiser, inactivation could be achieved at concentrations of 10 and 20 ppm with inactivation increasing with contact time up to 8 minutes, beyond which there was no significant benefit. Although most of theL. innocuastrains in the study responded similarly toL. monocytogeneswhen subjected to a single inactivation treatment, when the treatments were applied as hurdle, allL. innocuastrains except PFR16D08 were more sensitive than theL. monocytogenescocktail. PFR16D08 almost matched the resistance of theL. monocytogenescocktail but was much more resistant to the individual treaments. A cocktail of twoL. innocuastrains (PFR 05A07 and PFR 05A10) had the closest responses to the hurdle treatment to those of theL. monocytogenescocktail and is therefore recommended for hurdle experiments.ImportanceOwing to researcher safety risks it is often difficult to use actual pathogens, such asListeria monocytogenes, to explore different inactivation procedures under field conditions. Organisms that are closely related to the pathogen but without its virulence are therefore used as surrogates for the actual pathogen. However, this assumes that the surrogate will behave in a similar manner to the pathogen and it is difficult to predict the responses of the surrogate compared to the actual pathogen. This study compares the responses of individual and combined “cocktails” of strains of non-pathogenicListeria innocuato different inactivation procedures when compared to the response of a cocktail ofL. monocytogenes. Our study highlights the importance of evaluating a number of strains when choosing surrogates.

scholarly journals Analysis of process factors of dry fermented salami to control Listeria monocytogenes

2017 ◽  
Vol 6 (1) ◽  
Author(s):  
Enrico Novelli ◽  
Lucia Dal Santo ◽  
Stefania Balzan ◽  
Barbara Cardazzo ◽  
Dino Spolaor ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Protective Factor ◽  
Challenge Test ◽  
Potassium Nitrate ◽  
Black Pepper ◽  
Starter Cultures ◽  
Growth Potential ◽  
Main Concern ◽  
Challenge Tests ◽  
Process Factors

Challenge tests are a clear opportunity for manufacturers interested in the evaluation of their management system with the aim to reduce the spread of foodborne pathogens. This is a main concern especially in ready-to-eat food in relation to the risk associated with <em>Listeria monocytogenes</em>. For small and medium-scale food industry the manufacturing practices and products formulation are characterized by a wider variability and poor repeatability. The use of ad-hoc challenge test and the comparison among different processing systems are strongly required. This paper reports a preliminary comparison among different challenge tests (n=12) commissioned by three manufacturers of raw-fermented Salami during a period of three years (2013-2016). The challenge tests were designed to evaluate the growth potential (δ) of <em>L. monocytogenes</em> during the whole processing period of the Salami. The doughs were prepared according to different formulations: the simplest formulation was represented by the use of salt, potassium nitrate, black pepper and starter cultures while the most composited formulations also included the use of sugars and ascorbic acid in addition to nitrite salt. All the processing steps were conducted within an experimental laboratory dedicated for the processing of meat. After stuffing the salami were dried and ripened under temperature and relative humidity control. The sugar inclusion can be considered as protective factor, while the drying step at high temperature (above 20°C) was associated with higher δ values (δ&gt;0.5 log cfu/g). The addition of starter cultures, and the subsequent acidification highlighted the importance of pH as the parameter able to affect the L. monocytogenes growth.

scholarly journals Evaluation of growth potential and growth dynamics of Listeria monocytogenes on ready-to-eat fresh fruit

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
David Collu ◽  
Luisa Marras ◽  
Adriana Sanna ◽  
Gerolamo Carrucciu ◽  
Antonella Pinna ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Challenge Test ◽  
Growth Dynamics ◽  
Food Product ◽  
Growth Potential ◽  
Salmonella Spp ◽  
E Coli ◽  
Hygiene Practices ◽  
Short Period ◽  
Challenge Tests

The consumption of fresh or RTE fruits is increasing every year and Listeria monocytogenes has been identified on raw or minimally processed fruits. A food product can become contaminated with L. monocytogenes anywhere along the pathway of food production during planting, harvesting, packaging, distribution and serving. The aim of this work was to assess the microbiological risks associated with consumption of ready- to- eat fruit such as melon, pineapple, coconut and fruit salad. The presence of Escherichia coli, Salmonella spp. and L. monocytogenes was also evaluated. Microbiological challenge tests were carried out for the evaluation of the L. monocytogenes growth potential in RTE fruit stored at 4 and 8°C. E. coli counts resulted under the detection limit of 10 CFU g-1, Salmonella and L. monocytogenes were not detected (absence in 25g). The growth potential values in coconut and melon (δ>0.5) showed the growth capacity of Listeria at the temperatures considered. A low initial load, also derived from good hygiene practices, and correct storage temperatures are essential to reduce bacterial growth in RTE fruit. The challenge test showed how each type of RTE fruit has a different commercial life based on its specific growth potential and that food should be stored at temperatures not higher than 4°C for a short period.

Thermal inactivation and growth potential of Listeria innocua in rehydrated salt-cured cod prepared for ready-to-eat products

Food Control ◽  
2010 ◽  
Vol 21 (8) ◽  
pp. 1121-1126 ◽  
Author(s):  
Grete Lorentzen ◽  
Elinor Ytterstad ◽  
Ragnar L. Olsen ◽  
Taran Skjerdal
Keyword(s):  
Thermal Inactivation ◽  
Listeria Innocua ◽  
Growth Potential

A Predictive Model for the Inactivation of Listeria innocua in Cooked Poultry Products during Postpackage Pasteurization

2011 ◽  
Vol 74 (8) ◽  
pp. 1261-1267 ◽  
Author(s):  
MIN LI ◽  
ABANI PRADHAN ◽  
LISA COONEY ◽  
ANDY MAUROMOUSTAKOS ◽  
PHILIP CRANDALL ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Predictive Model ◽  
Thermal Inactivation ◽  
Hot Water ◽  
Listeria Innocua ◽  
Zone Method ◽  
Data Set ◽  
Poultry Products ◽  
Fully Cooked ◽  
Mean Square Errors

Contamination of Listeria monocytogenes in ready-to-eat poultry products poses potential risk of listeriosis to the public. To control the level of Listeria contamination, attention has been focused on the postpackage pasteurization of fully cooked poultry products. In this study, we sought to develop a model to predict the thermal inactivation of L. monocytogenes in chicken drumettes during postpackage hot water pasteurization. Fully cooked chicken drumettes were inoculated with Listeria innocua as a surrogate microorganism for Listeria monocytogenes, vacuum packaged, and treated in hot water baths at 60, 70, 80, and 90°C for different heating times. Experimental results showed that a 7-log CFU/g reduction of L. innocua occurred at 54, 28, 18, and 10 min at 60, 70, 80, and 90°C, respectively. The Weibull model was used to fit the survival curves of L. innocua at each heating temperature. The root mean square errors and residual plots indicated good agreements between the predicted and observed values. The predictive model was further validated by predicting a new data set generated in the pilot-plant tests. Model performance was evaluated by the acceptable prediction zone method, and the results indicated that the percentages of acceptable prediction errors were 100, 100, 82.4, and 87.5% at 60, 70, 80 and 90°C, respectively, which were all greater than the threshold acceptable value of 70%, indicating good performance of the model. The developed predictive model can be used as a tool to predict thermal inactivation behaviors of L. monocytogenes in ready-to-eat chicken drumettes products.

Modeling the Effects of Temperature, Sodium Chloride, and Green Tea and Their Interactions on the Thermal Inactivation of Listeria monocytogenes in Turkey†

2014 ◽  
Vol 77 (10) ◽  
pp. 1696-1702 ◽  
Author(s):  
VIJAY K. JUNEJA ◽  
JIMENA GARCIA-DÁVILA ◽  
JULIO CESAR LOPEZ-ROMERO ◽  
ETNA AIDA PENA-RAMOS ◽  
JUAN PEDRO CAMOU ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Sodium Chloride ◽  
Protective Effect ◽  
Heat Resistance ◽  
Green Tea ◽  
Thermal Inactivation ◽  
Heating Temperature ◽  
Lethal Effect ◽  
Interactive Effects ◽  
D Values

The interactive effects of heating temperature (55 to 65°C), sodium chloride (NaCl; 0 to 2%), and green tea 60% polyphenol extract (GTPE; 0 to 3%) on the heat resistance of a five-strain mixture of Listeria monocytogenes in ground turkey were determined. Thermal death times were quantified in bags that were submerged in a circulating water bath set at 55, 57, 60, 63, and 65°C. The recovery medium was tryptic soy agar supplemented with 0.6% yeast extract and 1% sodium pyruvate. D-values were analyzed by second-order response surface regression for temperature, NaCl, and GTPE. The data indicated that all three factors interacted to affect the inactivation of the pathogen. The D-values for turkey with no NaCl or GTPE at 55, 57, 60, 63, and 65°C were 36.3, 20.8, 13.2, 4.1, and 2.9 min, respectively. Although NaCl exhibited a concentration-dependent protective effect against heat lethality on L. monocytogenes in turkey, addition of GTPE rendered the pathogen more sensitive to the lethal effect of heat. GTPE levels up to 1.5% interacted with NaCl and reduced the protective effect of NaCl on heat resistance of the pathogen. Food processors can use the predictive model to design an appropriate heat treatment that would inactivate L. monocytogenes in cooked turkey products without adversely affecting the quality of the product.

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