Search results for "LISTERIA MONOCYTOGENES"
showing 10 items of 142 documents
Influence des conditions environnementales (statique versus dynamique) sur le développement en biofilm de Listeria monocytogenes EGD-e. Developpement…
2008
National audience
The σ B -dependent regulatory sRNA Rli47 represses isoleucine biosynthesis in Listeria monocytogenes through a direct interaction with the ilvA trans…
2019
International audience; The facultative intracellular pathogen Listeria monocytogenes can persist and grow in a diverse range of environmental conditions, both outside and within its mammalian host. The alternative sigma factor Sigma B (sigma(B)) plays an important role in this adaptability and is critical for the transition into the host. While some of the functions of the sigma(B) regulon in facilitating this transition are understood the role of sigma(B)-dependent small regulatory RNAs (sRNAs) remain poorly characterized. In this study, we focused on elucidating the function of Rli47, a sigma(B)-dependent sRNA that is highly induced in the intestine and in macrophages. Using a combinatio…
Essential oils as multi-target compounds for novel food safety strategies
This research work has been developed in the context of the potencial applications of essential oils as multi-target compounds for novel food safety strategies, such as active packaging technologies. Essential oils are aromatic oils derived from plants and usually extracted by hydrodistillation when intended to be used in food. There is an increasing interest in the antimicrobial properties of essential oils due to the possibility of using them to replace ‘synthetic’ preservatives in food or, in general, to reduce viable numbers of pathogens along the food chain.
A synthetic derivative of antimicrobial peptide holothuroidin 2 from mediterranean sea cucumber (Holothuria tubulosa) in the control of Listeria mono…
2019
Due to the limited number of available antibiotics, antimicrobial peptides (AMPs) are considered antimicrobial candidates to fight difficult-to-treat infections such as those associated with biofilms. Marine environments are precious sources of AMPs, as shown by the recent discovery of antibiofilm properties of Holothuroidin 2 (H2), an AMP produced by the Mediterranean sea cucumber Holothuria tubulosa. In this study, we considered the properties of a new H2 derivative, named H2d, and we tested it against seven strains of the dangerous foodborne pathogen Listeria monocytogenes. This peptide was more active than H2 in inhibiting the growth of planktonic L. monocytogenes and was able to interf…
Prevalence of Listeria sp. in droppings from urban rooks (Corvus frugilegus)
1997
Droppings from 112 urban rooks (Corvus frugilegus) were cultured for the presence of Listeria sp. Overall, 46% of rooks sampled harboured one or more Listeria species. Of all birds examined, 33%, 24% and 8%, respectively, were infected with Listeria monocytogenes, Listeria innocua and Listeria seeligeri. Differentiation of L. monocytogenes and L. seeligeri carried out by several phenotypic typing methods proved the diversity of strains and the major role of rooks which widely contribute to spreading this bacteria in our environment. The results also suggest that the ability to recover specific Listeria strains from the same sample is at least partially dependent on the methodology. These fi…
Ligands affecting silver antimicrobial efficacy on Listeria monocytogenes and Salmonella enterica
2013
Although silver is being extensively used in food or other applications as the key component to control microbial proliferation, many factors affecting its real potential are still unknown. In the present work, the presence of specific ligands or the contents in organic matter was correlated with silver speciation and its antibacterial performance. Silver was found to be only active in form of free silver ions (FSI). The presence of chloride ions produced an equilibrium of stable silver chloride complexes which were void of antimicrobial efficacy. However, even at relatively high concentrations of chlorides, a small fraction of FSI may still be present, producing a bactericidal effect with …
Design of biopolymeric matrices entrapping bioprotective lactic acid bacteria to control Listeria monocytogenes growth: Comparison of alginate and al…
2014
In order to design biopolymeric matrices entrapping bioprotective lactic acid bacteria (LAB) to control undesirable microorganisms growth in foods, the performances of alginate and alginate-caseinate (an aqueous two-phase system) matrices entrapping Lactococcus lactis subsp. lactis LAB3 cells were compared. Since efficient matrices should preserve the culturability and the antimicrobial activity of entrapped LAB3 cells for prolonged periods, they were both monitored for 12 days storage at 30 °C. Maximal cell density (∼109 CFU mL−1) was reached after 24 h whatever the matrix type. Then, the LAB3 cells population decreased: 107 and 106 CFU mL−1 were enumerated after 12 days in alginate-casein…
Chitosan films for the microbiological preservation of refrigerated sole and hake fillets
2013
The effect of chitosan films for shelf-life extension of fresh fillets of hake (Merluccius merluccius) and sole (Solea solea) was evaluated over a 15-day storage at 4 ± 1 °C. Fish fillets wrapped in a chitosan matrix were individually packaged in air (AP) and under vacuum (VP). Microbiological analyses (total aerobic mesophilic bacteria, Pseudomonas, H2S-producing bacteria, lactic acid bacteria, Enterobacteriaceae and Listeria monocytogenes were carried out during the shelf-life. The microbial species were inhibited (p < 0.05) by the presence of chitosan films, especially under VP conditions. A significant (p < 0.05) increase of the lag phase and a reduction of the final microbial populatio…
Control of Growth and Persistence of Listeria monocytogenes and β-Lactam-Resistant Escherichia coli by Thymol in Food Processing Settings
2020
The main objective of this study was to evaluate the efficacy of thymol in controlling environmental contamination in food processing facilities. The effect of thymol was tested as an agent to prevent planktonic and bacterial biofilm growth of twenty-five Listeria monocytogenes isolates from a variety of foods and five Escherichia coli isolates from a farm. The E. coli isolates were positive for extended spectrum &beta
Investigation of the hygienic safety of aromatic plants cultivated in soil contaminated with Listeria monocytogenes
2012
Abstract The present work was undertaken to investigate the survival of Listeria monocytogenes ATCC 19114T in soil during the whole crop cycle of rocket (Eruca sativa Mill.) and basil (Ocimum basilicum L.), to monitor its transfer to the leaves, and to evaluate its viability at harvest. To this purpose, the soil was N–P–K fertilized and four trials, obtained with different combinations of soil treatment, listerial inoculums and seed planting, were followed for each aromatic plant. Soil was weekly investigated for total microbial counts and L. monocytogenes evolution. At the starting time, un-inoculated autoclaved soil showed a limited microbial load (103 CFU g dw−1), while un-inoculated non…