Listeria monocytogenes

Thu, 03/19/2020 - 03:32
Author(s): Morandi Stefano, Tiziana Silvetti, Vito Vezzini, Elena Morozzo, Milena Brasca This study was aimed to evaluate the effectiveness of two lactic acid bacteria (LAB) cultures (Lactococcus lactis FT27 and Carnobacteroim divergens SCA), lactic acid/sodium lactate (LASL - L-lactic acid 61% (w/w) and L-sodium lactate 21% (w/w)) and their combination against four Listeria monocytogenes...
Thu, 03/19/2020 - 03:31
LWT
Author(s): Emmanuel O. Kyere, Grace Foong, Jon Palmer, Jason J. Wargent, Graham C. Fletcher, Steve Flint Foodborne outbreaks associated with fresh produce due to human pathogenic bacteria have become a global concern. In this study, we investigated the ability of three fresh produce associated L. monocytogenes strains: PFR O8A06 (coleslaw isolate), PFR O8A07 and O8A08 (cabbage isolates) to...
Wed, 03/18/2020 - 03:28
Overlapping transcription between the mRNAs of the neighbouring genes is a common process in bacteria. The resulting paired RNAs are digested genome‐wide by the action of the double‐stranded endoribonuclease RNase III. New examples of gene arrangements where overlapping transcription plays a key role are summarised to explain our current understanding regarding how overlapping transcription may...
Wed, 03/18/2020 - 03:28
Serovar 4b strains of L. monocytogenes possess galactosylated WTAs and LTAs. We show that two different genes, gtlB and gttB encode two distinct glycosyltransferases required for the galactosylation of LTA and WTA respectively. Deletion of these genes reveals that the galactose decoration on WTA but not LTA is responsible for the surface retention and function of the important virulence factor...
Wed, 03/18/2020 - 03:28
Contrary to other human bacterial pathogens, most strains of the human pathogen L. monocytogenes have preserved along decades susceptibility to the key‐drugs used to treat human infections. L. monocytogenes has a large core‐genome (present in all strains of the species), allowing to adapt to multiple environmental niches without the need of recruiting accessory genes from other species by...
Wed, 03/18/2020 - 03:28
The universe of Molecular Microbial Pathogenesis is filled with many female and male stars. But there are two particularly bright shining supernovae‐like stars: the late Stanley Falkow and the very lively and creative Pascale Cossart. These two outstanding luminaries, surrounded by numerous planets, do not only belong to different scientific generations but their splendor also comes from very...
Tue, 03/17/2020 - 03:34
The capacity of Listeria monocytogenes to adapt to environmental changes is facilitated by a large number of regulatory proteins encoded within its genome. Among these proteins are the uncharacterized LysR-type transcriptional regulators (LTTRs). LTTRs can work as positive and/or negative transcription regulators at both local and global genetic levels. Previously, our group determined by...
Tue, 03/17/2020 - 03:34
Listeria monocytogenes is a Gram-positive pathogen able to cause severe human infections. Its major virulence regulator is the transcriptional activator PrfA, a member of the Crp/Fnr family of transcriptional regulators. To establish a successful L. monocytogenes infection, the PrfA protein needs to be in an active conformation, either by binding the cognate inducer glutathione (GSH) or by...
Tue, 03/17/2020 - 03:33
Author(s): Lina Sheng, Zheng Zhang, Gang Sun, Luxin Wang Due to the lack of thermal inactivation steps, the fresh produce industry is actively looking for new, environmentally friendly and effective non-thermal control strategies to eliminate foodborne pathogens on produce surfaces and to prevent cross-contamination. Photodynamic inactivation of bacteria has emerged as a novel alternative...
Sun, 03/15/2020 - 04:01
Author(s): Taekeon Jung, Yugyung Jung, Jaehyeon Ahn, Sung Yang Most biosensors use small amounts (a few tens of microliters) of a sample to detect bacteria. However, it is necessary to detect bacteria with at least a few milliliters of the sample to obtain statistically significant results. Therefore, the bacteria concentration process is critical for the rapid and accurate detection of bacteria...
Fri, 03/13/2020 - 03:33
Older adults are at higher risk of invasive listeriosis compared with the general population.  Some foods are more likely than others to be contaminated with or contain high levels of Listeria monocytogenes . The objectives of this study were to, 1) determine dietary consumption patterns, among older adults in the United States; 2) evaluate sociodemographic and economic characteristics of older...
Thu, 03/12/2020 - 03:36
by Lene Bungenstock, Amir Abdulmawjood, Felix Reich With regards to the frequently reported findings of spoilage bacteria and pathogens in various foods there is a need to explore new ways to control hazards in food production and to improve consumer safety. Fermented sausages from traditional and industrial production in Germany were screened for lactic acid bacteria with antibacterial effects...
Wed, 03/11/2020 - 03:26
Due to rhizodeposits and various microbial interactions, the rhizosphere is an extremely dynamic system, which provides a conductive niche not only for bacteria beneficial to plants but also for those that might pose a potential threat to humans. The importance of bioinoculants as biocontrol agents to combat phytopathogens has been widely recognized. However, little information exists with...
Sun, 03/08/2020 - 04:35
Novel nanosized biomass-based pH-responsive cellulose nanofibers (CNF-PEI) with excellent biocompatibility were tailored by grafting polyethylenimine (PEI) onto carboxylated cellulose nanofibers (CNF-COOH); the active site (−COOH, 0.96 mmol/g) was anchored on cellulose nanofibers (CNFs) to introduce PEI with a high density (10.57 mmol/g) of amino groups. The as-prepared CNF-PEI not only...
Wed, 03/04/2020 - 04:01
Author(s): Ranju Paudyal, Conor P. O'Byrne, Kimon-Andreas Karatzas The Glutamate Decarboxylase (GAD) system is important for survival of L. monocytogenes and other microorganisms under acidic conditions. Environmental conditions influence the function of the GAD system. Until now, the only conditions known to lead to increased transcription of the GAD system are the stationary phase in rich media...
Wed, 03/04/2020 - 03:56
Listeria monocytogenes is often responsible for postprocessing contamination of ready‐to‐eat (RTE) products including cooked ham. As an emerging technology, atmospheric cold plasma (ACP) has the potential to inactivate L. monocytogenes in packaged RTE meats. The objectives of this study were to evaluate the effect of treatment time, modified atmosphere gas compositions (MAP), ham formulation, and...
Wed, 03/04/2020 - 01:19
Antimicrobial seed treatments recommended by Canadian guidance for sprouted vegetable production (2,000 ppm hypochlorite for 15-20 minutes or 6-10% hydrogen peroxide for 10 minutes at room temperature) are not fully compliant with organic production principles. We investigated the effect of a sequential treatment consisting of a 10 min soak at 50 0 C in water followed by exposure to a 2.0% H 2 O...
Wed, 03/04/2020 - 01:19
The microbiological quality of ready-to-eat (RTE) foods from school cafeterias in Chongqing, China, was evaluated in comparison to a guideline published by a provincial health commission. Based on their preparation processes and potential risks, the RTE foods were divided into 5 types: food type 1, general cooked and hot-held foods; food type 2, cooked meats; food type 3, heated aquatic products...
Wed, 03/04/2020 - 01:19
We evaluated high pressure processing to lower levels of Shiga toxin-producing Escherichia coli (STEC) and Listeria monocytogenes inoculated into samples of plant or beef burgers. Multi-strain cocktails of STEC and L. monocytogenes were separately inoculated (ca. 7.0 log CFU/g) into plant burgers or ground beef. Refrigerated (i.e., 4°C) or frozen (i.e., -20°C) samples (25-g each) were...
Wed, 03/04/2020 - 01:19
Canadian First Nations communities rely on traditional preservation methods such as  the smoking, drying, and canning of fish and game meats, to ensure long-term food security. Unlike commercial food production, there are no recognized official standards for these methods, thus rendering their efficacy in producing microbiologically safe foods relatively unknown. In this study, 81 fresh or...
Wed, 03/04/2020 - 01:19
The documented survival of pathogenic bacteria including Listeria monocytogenes (LM), shiga toxin-producing Escherichia coli (STEC), and Salmonella during the manufacture and aging of some cheeses highlights the need for additional interventions to enhance food safety. Unfortunately, few interventions are compliant with the Standards of Identity for cheese. Protective bacterial cultures (PC)...
Wed, 03/04/2020 - 01:19
Listeria monocytogenes is a potential hazard for food safety and therefore public health. The aim of the present study was to determine the prevalence and characteristics of L. monocytogenes in Polish ready-to-eat (RTE) meat products in retail. Among the 184 439 food samples collected within the framework of national official control and monitoring program only 0.3% were  positive for L....
Wed, 03/04/2020 - 01:19
Process control validations require knowledge of the resistance of the pathogen(s) of concern to the target treatment, and, in some cases, the relative resistance of surrogate organisms. Selected strains of Escherichia coli O157:H7 (five strains), Listeria monocytogenes (five strains), and Salmonella enterica (five strains) as well as Salmonella Enteritidis phage type (PT) 30 and nonpathogenic ...
Wed, 03/04/2020 - 01:18
Listeria monocytogenes, a resilient and ubiquitous foodborne pathogen, is associated with a high case-fatality rate in humans. This study investigated the culturable microbiota of low-moisture foods (LMFs) imported into Canada to see how well bacteria isolated from these foods could inhibit/inactivate the growth of L. monocytogenes. Imported LMFs were acquired from various supermarkets in the...
Wed, 03/04/2020 - 01:18
Understanding a food’s ability to support the growth and/or survival of a pathogen throughout the supply chain is essential to minimizing large-scale contamination events. The purpose of this study was to examine the behavior (growth and/or survival) of Listeria monocytogeneson broccoli and cauliflower florets stored under different post-harvest temperatures utilized along the supply chain....
Wed, 03/04/2020 - 01:18
We evaluated high pressure processing to lower levels of Shiga toxin-producing Escherichia coli (STEC) and Listeria monocytogenes inoculated into samples of plant or beef burgers. Multi-strain cocktails of STEC and L. monocytogenes were separately inoculated (ca. 7.0 log CFU/g) into plant burgers or ground beef. Refrigerated (i.e., 4°C) or frozen (i.e., -20°C) samples (25-g each) were...
Wed, 03/04/2020 - 01:18
Listeria monocytogenes is a potential hazard for food safety and therefore public health. The aim of the present study was to determine the prevalence and characteristics of L. monocytogenes in Polish ready-to-eat (RTE) meat products in retail. Among the 184 439 food samples collected within the framework of national official control and monitoring program only 0.3% were positive for L....
Tue, 03/03/2020 - 10:09
Luchansky, J. B., A. C. S. Porto-Fett, and B. Chapman. Food safety-related infrastructure, procedures, and practices at grocery stores play an important role in protecting public health. Thus, as part of a companion study to establish the "true" prevalence of Listeria monocytogenes among ready-to-eat (RTE) foods purchased at retail stores, digital photographs were recorded by data collectors...
Tue, 03/03/2020 - 03:37
Whole-genome sequencing (WGS) is becoming the standard method for subtyping Listeria monocytogenes. Interpretation of WGS data for isolates from foods and associated environments is, however, challenging due to a lack of detailed data on Listeria evolution in processing facilities. Here, we used previously collected WGS data for 40 L. monocytogenes isolates obtained from a cold-smoked salmon...
Tue, 03/03/2020 - 03:37
Listeria monocytogenes causes the severe foodborne illness listeriosis and survives in food-associated environments due to its high stress tolerance. A data assembly and analysis protocol for microbial growth experiments was compiled to elucidate the strain variability of L. monocytogenes stress tolerance. The protocol includes measurement of growth ability under stress (step 1), selection of a...
Fri, 02/28/2020 - 03:27
Microorganisms in dairy industries can form monospecies, dual-species, or multispecies biofilms, showing cooperative or competitive behaviors, which might contribute to the reduction of efficiency of cleaning and sanitization processes and eventually turn into a potential source of contamination. This study proposes to evaluate the behavior of Listeria monocytogenes in monospecies biofilms,...
Thu, 02/27/2020 - 04:00
LWT
Author(s): Xiaomin Yu, Xiaoli Wu, Nagendra P. Shah, Feng XuIn this study, we found that the antioxidant activity of Bifidobacterium bifidum WBBI03 and Listeria monocytogenes CMCC 54001 was increased after co-incubation. Therefore, the molecular mechanism of enhancing antioxidant activity was explored through isobaric tags for relative and absolute quantitation (iTRAQ). Analysis of differentially...
Thu, 02/27/2020 - 03:47
Liposomes have been broadly studied as delivery systems for bioactive compounds, although its relatively low stability remains a limitation for commercial application. In this study, phosphatidylcholine (PC) liposomes were prepared entrapping a mixture of garlic extract (GE) and nisin (Nis) using cholesterol (CHO), oleic acid (OA), or octadecylamine (ODA) as membrane stabilizers to evaluate their...
Wed, 02/26/2020 - 03:36
ABSTRACT Listeria monocytogenes moves from one cell to another using actin-rich membrane protrusions that propel the bacterium toward neighboring cells. Despite cholesterol being required for this transfer process, the precise host internalization mechanism remains elusive. Here, we show that caveolin endocytosis is key to this event as bacterial cell-to-cell transfer is severely impaired when...
Wed, 02/26/2020 - 03:36
ABSTRACT Mitochondrial function adapts to cellular demands and is affected by the ability of the organelle to undergo fusion and fission in response to physiological and nonphysiological cues. We previously showed that infection with the human bacterial pathogen Listeria monocytogenes elicits transient mitochondrial fission and a drop in mitochondrion-dependent energy production through a...
Tue, 02/25/2020 - 03:41
In Listeria monocytogenes the full details of how stress signals are integrated into the B regulatory pathway are not yet available. To help shed light on this question we investigated a collection of transposon mutants that were predicted to have compromised activity of the alternative sigma factor B (B). These mutants were tested for acid tolerance, a trait that is known to be under B...
Sat, 02/22/2020 - 03:28
In Rhizobium-legume symbiosis, the bacteria are converted into nitrogen-fixing bacteroids. In many legume species, differentiation of the endosymbiotic bacteria is irreversible, culminating in definitive loss of their cell division ability. This terminal differentiation is mediated by plant peptides produced in the symbiotic cells. In Medicago truncatula more than ∼700 nodule-specific cysteine-...
Sat, 02/22/2020 - 03:28
Listeria monocytogenes (LM) is a gram-positive facultative intracellular pathogen that could stimulate host to produce inflammatory response, cell-mediated immunity, and humoral immunity. In this study, an attenuated live vector vaccine for Aeromonas hydrophila (AH) named EGDeABdd-dat-ompW was successfully constructed using an attenuated vector named EGDeABdd, in which dal, dat, actA, and inlB...
Fri, 02/21/2020 - 04:14
Author(s): Inês Azevedo, Joana Barbosa, Helena Albano, Paula TeixeiraAbstractIn response to nutritional and health concerns, the food industry has begun to offer a wider variety of products that reflect changing consumer preferences. In addition to traditional alheiras, made with pork and/or poultry meats, other varieties of alheiras (“innovative”) made from codfish, mushrooms, tofu, soy and...
Fri, 02/21/2020 - 04:14
Author(s): John Burnett, Sophie Tongyu Wu, Henk C. den Bakker, Peter W. Cook, Deklin R. Veenhuizen, Susan R. Hammons, Manpreet Singh, Haley F. OliverAbstractThe purpose of this study was to determine the prevalence of Listeria monocytogenes and Salmonella enterica in retail produce environments and to elucidate possible ecological niches. Thirty environmental samples per store were collected...
Thu, 02/20/2020 - 03:35
Author(s): Mohammad M. ObaidatAbstrcatThis study characterized Listeria monocytogenes, Salmonella enterica, and E. coli O157:H7 by collecting rectoanal mucosal swabs and fecal samples from 518 imported beef cattle at Jordan’s major abattoir. A unique 53 L. monocytogenes, 287 S. enterica, and 17 E. coli O157:H7 were isolated from 37, 120 and 9 different animals; respectively. The prevalence of S....
Thu, 02/20/2020 - 03:29
The sessile biofilms of Vibrio parahaemolyticus and Listeria monocytogenes have increasingly become a critical threat in seafood safety. This study aimed to evaluate the effects of modified atmospheres on the formation ability of V. parahaemolyticus and L. monocytogenes biofilms. The stress responses of bacterial biofilm formation to modified atmospheres including anaerobiosis (20% carbon dioxide...
Wed, 02/19/2020 - 03:43
ABSTRACT Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is a major cause of soft tissue infections in dogs and occasionally infects humans. Hypervirulent multidrug-resistant (MDR) MRSP clones have emerged globally. The sequence types ST71 and ST68, the major epidemic clones of Europe and North America, respectively, have spread to other regions. The genetic factors underlying the...
Wed, 02/19/2020 - 03:31
The facultative intracellular pathogen Listeria monocytogenes uses an actin-based motility process to spread within human tissues. Filamentous actin from the human cell forms a tail behind bacteria, propelling microbes through the cytoplasm. Motile bacteria remodel the host plasma membrane into protrusions that are internalized by neighboring cells. A critical unresolved...
Tue, 02/18/2020 - 03:26
In the present study, the antimicrobial and the insect repellent activity of 16 botanical extracts obtained by supercritical CO2 (SCF) extraction were evaluated. The present investigation was conducted as there is a necessity for exploration of natural botanical extracts that target both stored product insects and microbes. The antimicrobial activity was studied by disc diffusion and broth...
Mon, 02/17/2020 - 03:28
Assays to evaluate killing of Listeria monocytogenes by the protozoan Tetrahymena pyriformis were developed. Listeria were killed at an exponential rate for the first 4 hr of coculture with Tetrahymena. Nineteen diverse strains of Listeria were equally susceptible to killing by Tetrahymena. Tetrahymena phagocytized and killed both planktonic and adherent Listeria. Abstract Bactivory by protozoa...
Sat, 02/15/2020 - 03:36
Author(s): María Jesús Gracia, Regina Lázaro, Consuelo Pérez-Arquillué, Rafael Pagán, Sergio Ramos, João Luis Garcia, Susana BayarriAbstractRaw and dry-cured meats have been identified as a potential source of Toxoplasma gondii infection for humans. The present study evaluated the efficacy of an alternative non-thermal food-processing treatment, high hydrostatic pressure, on the viability of T....
Sat, 02/15/2020 - 03:25
Invited review: Advances in nisin use for preservation of dairy products. By Ibarra-Sánchez et al., page 2041. Dairy products, in particular nonfermented products, are prone to contamination with foodborne pathogens, such as Listeria monocytogenes, Staphylococcus aureus, and Salmonella spp. Nisin, a widely used antimicrobial, is effective in certain dairy products. In this review, we discuss the...
Wed, 02/12/2020 - 10:50
Author(s): Aidin Shafipour Yordshahi, Mehran Moradi, Hossein Tajik, Rahim MolaeiAbstractLyophilized postbiotics of Lactobacillus plantarum was prepared and impregnated in bacterial nanocellulose (BNC) by ex-situ method to develop an antimicrobial ground meat wrapping nanopaper. The postbiotics incorporated BNC (P-BNC) films were optimized by response surface methodology and their antimicrobial...
Wed, 02/12/2020 - 03:27
Study objective was to determine efficacy of a bacteriophage suspension against Listeria spp. when applied to three common types of materials used in food manufacturing facilities. Materials included two food contact materials (stainless steel and polyurethane thermoplastic belting) and one noncontact material (epoxy flooring). Coupons of each material were inoculated with a cocktail containing L...

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