<i>Listeria monocytogenes</i>: biofilm formation and persistence in food-processing environments

Møretrø, Trond; Langsrud, Solveig

doi:10.1017/s1479050504001322

Cited by 291 publications

(194 citation statements)

References 97 publications

(184 reference statements)

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“…In the biofilm, the cells are embedded in a self-produced matrix and protected against environmental stress, e.g., disinfectants (14)(15)(16)(17). A correlation between biofilm-forming abilities and persistence in food and feed-producing facilities has been reported for Salmonella enterica (18) and Listeria monocytogenes (19), and it has been suggested that biofilms in food-producing environments may serve as reservoirs for bacteria that may contaminate the food products. Furthermore, we have previously shown that dissemination of virulence genes like stx can occur in E. coli biofilm (20).…”

mentioning

confidence: 99%

Potentially Pathogenic Escherichia coli Can Form a Biofilm under Conditions Relevant to the Food Production Chain

Nesse

Sekse

Berg

et al. 2014

Appl Environ Microbiol

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The biofilm-producing abilities of potentially human-pathogenic serotypes of Escherichia coli from the ovine reservoir were studied at different temperatures and on different surfaces. A possible influence of the hydrophobicity of the bacterial cells, as well as the presence of two virulence factors, the Shiga toxin-encoding (Stx) bacteriophage and the eae gene, was also studied. A total of 99 E. coli isolates of serotypes O26:H11, O103:H2, and O103:H25 isolated from sheep feces were included. The results show that isolates of all three E. coli serotypes investigated can produce biofilm on stainless steel, glass, and polystyrene at 12, 20, and 37°C. There was a good general correlation between the results obtained on the different surfaces. E. coli O103:H2 isolates produced much more biofilm than those of the other two serotypes at all three temperatures. In addition, isolates of serotype O26:H11 produced more biofilm than those of O103:H25 at 37°C. The hydrophobicity of the isolates varied between serotypes and was also influenced by temperature. The results strongly indicated that hydrophobicity influenced the attachment of the bacteria rather than their ability to form biofilm once attached. Isolates with the eae gene produced less biofilm at 37°C than isolates without this gene. The presence of a Stx bacteriophage did not influence biofilm production. In conclusion, our results show that potentially human-pathogenic E. coli from the ovine reservoir can form biofilm on various surfaces and at several temperatures relevant for food production and handling.

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confidence: 99%

Potentially Pathogenic Escherichia coli Can Form a Biofilm under Conditions Relevant to the Food Production Chain

Nesse

Sekse

Berg

et al. 2014

Appl Environ Microbiol

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“…In other cases, postpasteurization contamination of product was identified as the cause of listeriosis (30). Various studies have indicated that certain strains of L. monocytogenes survive within the food-processing environment, and the persistence of such strains in a food-processing plant is of particular concern as they have the potential to act as a source of contamination of the processed product (22,25,26,27). The possible generation and establishment of stress-resistant L. monocytogenes variants in food-processing environments remains a critical challenge to the food industry.…”

Section: Discussionmentioning

confidence: 99%

Isolation of Highly Heat-Resistant Listeria monocytogenes Variants by Use of a Kinetic Modeling-Based Sampling Scheme

Boeijen

Francke

Moezelaar

et al. 2011

Appl Environ Microbiol

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Stable high-hydrostatic-pressure (HHP)-resistant Listeria monocytogenes LO28 variants were previously isolated and characterized. These HHP variants were also more resistant to heat. In addition, nonlinear heat inactivation kinetics pointed toward the existence of heat-resistant variants, although these could not be isolated so far. In this study, we used kinetic modeling of inactivation curves of two isolated HHP variants and their wild type, and this revealed that the probability of finding resistant variants should depend on the nature of the inactivation treatment and the time of exposure. At specific heat and HHP conditions, resistant LO28 and EGDe variants were indeed isolated. Resistant LO28 variants were even isolated after a heat inactivation at 72°C in milk, and these variants showed high resistance to standard pasteurization conditions. The increased resistance of part of the isolated LO28 and EGDe variants was due to mutations in their ctsR genes. For the variants whose ctsR genes and upstream regions were not altered, the mechanisms leading to increased resistance remain to be elucidated. This research showed the strength of kinetic modeling in unraveling the causes of nonlinear inactivation and facilitating the isolation of heat-resistant L. monocytogenes variants.Listeria monocytogenes can cause listeriosis in animal and human populations. Human listeriosis is a rare but severe disease and is one of the leading causes of death among patients with food-borne diseases in the United States. The estimated annual rate of invasive listeriosis in the United States is 3 cases and for countries within the European Union is 2 to 10 cases per million people per year (33). Recently, several European countries experienced an apparent increase in the incidence of listeriosis (13).A specific characteristic of L. monocytogenes that appears to be critical to its ability to cause human food-borne illness is its capacity to survive under harsh conditions. The occurrence of variants and the generation of population heterogeneity are factors that may contribute to the survival capacity of L. monocytogenes. Previous research showed that heterogeneity in L. monocytogenes populations (strains EGDe, LO28, and Scott A) affects resistance to high hydrostatic pressure (HHP). Inactivation of such heterogeneous populations resulted in survival curves with significant tailing, indicating the presence of an HHP-sensitive and an HHP-resistant fraction (32). Analysis of the cells that survived such HHP treatments revealed that the higher resistance of LO28 (32) and Scott A (17, 18) was a stable feature for part of the resistant fraction. Contrary to these results, no stable HHP-resistant isolates were obtained for EGDe (32). A significant fraction of the stably resistant variants of both Scott A and LO28 had an altered ctsR gene. This gene encodes CtsR, a DNA binding protein that regulates class III heat shock genes (7). The observed alterations in ctsR resulted not only in increased resistance to high pressure but also in increas...

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“…Chicken is heat-treated before consumption and this treatment normally eliminates pathogens. However, L. monocytogenes may be present in the food processing environment [40] and thus cross-contamination can occur during processes following heat treatment, via for example equipment when slicing or dicing and human handling. However, chicken meat is not known to be an important vehicle of foodborne human listeriosis and L. monocytogenes was detected in only 1.6% of the RTE chicken meat analysed in the EU in 2013 [38], which is no higher than the prevalence reported for other common salad ingredients.…”

Section: Bacteriological Safety Of Mixed-ingredient Saladsmentioning

confidence: 99%

Is your lunch salad safe to eat? Occurrence of bacterial pathogens and potential for pathogen growth in pre-packed ready-to-eat mixed-ingredient salads

Söderqvist

2017

Infection Ecology & Epidemiology

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As part of a trend toward healthy convenience foods, ready-to-eat (RTE) mixed-ingredient salads have become popular products among consumers. A mixed-ingredient salad contains combinations of raw (e.g. leafy vegetables and tomatoes) and processed (e.g. chicken, salmon, ham, pasta and couscous) ingredients. Contamination of leafy vegetables can occur during any step in the production chain and, since there is no step that kills pathogens, a completely safe final product can never be guaranteed. Meat ingredients, for example poultry meat and ham, are generally heat-treated before preparation, but may be contaminated after this treatment, e.g. when diced or sliced. When several ingredients are mixed together, cross-contamination may occur. Preparation of mixed-ingredient salads requires human handling, which presents an additional risk of bacterial contamination. With high-protein ingredients, e.g. cooked meat, the mixed-ingredient salad represents an excellent substrate for bacterial growth. This article reviews current knowledge regarding human bacterial pathogen prevalence in mixed-ingredient salads and the potential for pathogen growth in this product during storage.

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Listeria monocytogenes: biofilm formation and persistence in food-processing environments

Cited by 291 publications

References 97 publications

Potentially Pathogenic Escherichia coli Can Form a Biofilm under Conditions Relevant to the Food Production Chain

Potentially Pathogenic Escherichia coli Can Form a Biofilm under Conditions Relevant to the Food Production Chain

Isolation of Highly Heat-Resistant Listeria monocytogenes Variants by Use of a Kinetic Modeling-Based Sampling Scheme

Is your lunch salad safe to eat? Occurrence of bacterial pathogens and potential for pathogen growth in pre-packed ready-to-eat mixed-ingredient salads

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