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Listeria screening

Amin N Olaimat, Murad A Al-Holy, Mahmoud Abu Ghoush, Anas A Al-Nabulsi, Richard A Holley
Hummus (chickpea dip) is a ready-to-eat product which has been implicated in several foodborne outbreaks and food recalls. This study aimed to screen the antimicrobial activity of allyl isothiocyanate (AITC) against 5 strains of each of Salmonella enterica and Listeria monocytogenes using a disc diffusion method. Additionally, the antimicrobial activity of 0.1-1.5% (v/w) AITC against both pathogens and aerobic bacteria in hummus was also investigated. The inhibition zones of AITC were 8.5-15 and 7.0-8.5 mm against the S...
April 21, 2018: International Journal of Food Microbiology
Kyung-A An, Yunhee Jo, Kashif Akram, Sang-Cheol Suh, Joong-Ho Kwon
BACKGROUND: High microbial load is a serious concern in terms of the health-related safety of products of animal origin. In this study, the microbial loads of commercial frozen duck meat products, including bone-in whole raw, boneless sliced raw, and boneless whole smoked were investigated for pathogenic contamination. In addition, application of electron beam irradiation was also investigated. RESULTS: The samples revealed a serious microbial threat (102 -105 CFU/g for total aerobic bacteria and positive for foodborne pathogens) that required an effective decontamination technology...
April 20, 2018: Journal of the Science of Food and Agriculture
Sirirat Wachiralurpan, Thayat Sriyapai, Supatra Areekit, Pichapak Sriyapai, Suphitcha Augkarawaritsawong, Somchai Santiwatanakul, Kosum Chansiri
Listeria monocytogenes is a major foodborne pathogen of global health concern. Herein, the rapid diagnosis of L. monocytogenes has been achieved using loop-mediated isothermal amplification (LAMP) based on the phosphatidylcholine-phospholipase C gene ( plcB ). Colorimetric detection was then performed through the formation of DNA concatemers and a gold nanoparticle/DNA probe complex (GNP/DNA probe). The overall detection process was accomplished within approximately 1 h with no need for complicated equipment...
2018: Frontiers in Chemistry
Frédérique Pasquali, Federica Palma, Laurent Guillier, Alex Lucchi, Alessandra De Cesare, Gerardo Manfreda
Listeria monocytogenes is a foodborne pathogen adapted to survive and persist in multiple environments. Following two previous studies on prevalence and virulence of L. monocytogenes ST121 and ST14 repeatedly collected in a the same rabbit-meat processing plant, the research questions of the present study were to: (1) assess persistence of L. monocytogenes isolates from the rabbit-plant; (2) select genes associated to physiological adaptation to the food-processing environment; (3) compare presence/absence/truncation of these genes in newly sequenced and publicly available ST121 and ST14 genomes...
2018: Frontiers in Microbiology
Charles F Forney, Lihua Fan, Gregory S Bezanson, Timothy C Ells, Denyse I LeBlanc, Sherry Fillmore
Rapid methods to detect bacterial pathogens on food and strategies to control them are needed to mitigate consumer risk. This study assessed volatile emissions from whole cantaloupe melons (Cucumis melo) as an indicator of Listeria contamination and in response to steam vapor decontamination. Cantaloupe were inoculated with Listeria innocua, a nonpathogenic surrogate for L. monocytogenes, then exposed to 85 °C steam for 240 s (4 min) followed by rapid chilling and storage for 0, 7, 10, or 14 days at 4, 7, or 10 °C...
April 2018: Journal of Food Science
Brittney N Wyatt, Leggy A Arnold, Martin St Maurice
Pyruvate carboxylase (PC) catalyzes the conversion of pyruvate to oxaloacetate (OAA), an important metabolic reaction in a wide range of organisms. Small molecules directed against PC would enable detailed studies on the metabolic role of this enzyme and would have the potential to be developed into pharmacological agents. Currently, specific and potent small molecule regulators of PC are unavailable. To assist in efforts to find, develop, and characterize small molecule effectors of PC, a novel fixed-time assay has been developed based on the reaction of OAA with the diazonium salt, Fast Violet B (FVB), which produces a colored adduct with an absorbance maximum at 530 nm...
April 12, 2018: Analytical Biochemistry
Barbara Guantario, Paola Zinno, Emily Schifano, Marianna Roselli, Giuditta Perozzi, Claudio Palleschi, Daniela Uccelletti, Chiara Devirgiliis
Table olives are increasingly recognized as a vehicle as well as a source of probiotic bacteria, especially those fermented with traditional procedures based on the activity of indigenous microbial consortia, originating from local environments. In the present study, we report characterization at the species level of 49 Lactic Acid Bacteria (LAB) strains deriving from Nocellara del Belice table olives fermented with the Spanish or Castelvetrano methods, recently isolated in our previous work. Ribosomal 16S DNA analysis allowed identification of 4 Enterococcus gallinarum , 3 E...
2018: Frontiers in Microbiology
Siyue Gao, Brooke Pearson, Lili He
The existence of pathogenic bacteria in drinking water has been a threat to the safety of human well-being. Traditional methods to detect bacteria are standard plate counts or rapid methods such as ELISA and PCR. However, those methods can be time-consuming or require pre-enrichment when detecting low concentrations of bacteria. Filter membrane has been used for bacteria collection and culturing when monitoring environmental water samples. In this study, we applied surface enhanced Raman spectroscopy (SERS) to rapidly screen bacteria cells on a filter membrane based on the unique signal from an indicator molecule, 4-mercaptophenylboronic acid (4-mpba), that can specifically bind to the surface of bacteria through diol group in its structure and give off consistent SERS signal...
April 2018: Journal of Microbiological Methods
Fulai Li, Fan Li, Dan Luo, Weihua Lai, Yonghua Xiong, Hengyi Xu
Infectious diseases caused by Listeria monocytogenes pose a great threat to public health worldwide. Therefore, a rapid and efficient method for L. monocytogenes detection is needed. In this study, a biotin-exposure-based immunomagnetic separation (IMS) method was developed. That is, biotinylated antibody was first targeted to L. monocytogenes. Then, streptavidin-functionalized magnetic nanoparticles were added and anchored onto L. monocytogenes cells indirectly through the strong noncovalent interaction between streptavidin and biotin...
August 9, 2018: Analytica Chimica Acta
Alejandro Garrido-Maestu, Sarah Azinheiro, Joana Carvalho, Marta Prado
Listeria monocytogenes continues to be one of the most important foodborne pathogens worldwide, either due to its incidence and/or to its high mortality rate. In the present study, a filtration-based protocol was applied for the screening of viable bacteria. Additionally, a complete method (enrichment, filtration, DNA extraction and real-time PCR detection) was evaluated in order to determine the capacity of this protocol to detect viable L. monocytogenes in food samples. A new multiplex qPCR detection system was designed, including an internal amplification control, both targets were detected with hydrolysis probes...
August 2018: Food Microbiology
Melaine A Kuenemann, Patricia A Spears, Paul E Orndorff, Denis Fourches
Peptidoglycan walls of gram positive bacteria are functionalized by glycopolymers called wall teichoic acid (WTA). In Listeria monocytogenes, multiple enzymes including the glucose-1-phosphate uridylyltransferase (GalU) were identified as mandatory for WTA galactosylation, so that the inhibition of GalU is associated with a significant attenuation of Listeria virulence. Herein, we report on a series of in silico predicted GalU inhibitors identified using structure-based virtual screening and experimentally validated to be effective in blocking the WTA galactosylation pathway in vitro...
March 8, 2018: Molecular Informatics
Marilize Le Roes-Hill, Kim Durrell, Alaric Prins, Paul R Meyers
The actinobacterium, strain M26T , was isolated from garden soil that was pre-treated with microwave radiation. The soil sample was collected in Roodepoort, Gauteng Province, South Africa as part of an antibiotic-screening programme. The isolate produced branched vegetative mycelium with sporangiophores bearing small sporangia ranging from 3 to 6 μm in diameter. Rapid genus identification revealed that the isolate belongs to the genus Streptosporangium. To confirm this result, the strain was subjected to polyphasic taxonomic characterisation...
March 7, 2018: Journal of Antibiotics
P Carvajal-Rondanelli, M Aróstica, C A Álvarez, C Ojeda, F Albericio, L F Aguilar, S H Marshall, F Guzmán
Previous work demonstrated that lysine homopeptides adopt a polyproline II (PPII) structure. Lysine homopeptides with odd number of residues, especially with 11 residues (K11), were capable of inhibiting the growth of a broader spectrum of bacteria than those with an even number. Confocal studies also determined that K11 was able to localize exclusively in the bacterial membrane, leading to cell death. In this work, the mechanism of action of this peptide was further analyzed focused on examining the structural changes in bacterial membrane induced by K11, and in K11 itself when interacting with bacterial membrane lipids...
May 2018: Amino Acids
Quach Ngoc Tung, Nico Linzner, Vu Van Loi, Haike Antelmann
Gram-negative bacteria utilize glutathione (GSH) as their major LMW thiol. However, most Gram-positive bacteria do not encode enzymes for GSH biosynthesis and produce instead alternative LMW thiols, such as bacillithiol (BSH) and mycothiol (MSH). BSH is utilized by Firmicutes and MSH is the major LMW thiol of Actinomycetes. LMW thiols are required to maintain the reduced state of the cytoplasm, but are also involved in virulence mechanisms in human pathogens, such as Staphylococcus aureus, Mycobacterium tuberculosis, Streptococcus pneumoniae, Salmonella enterica subsp...
February 15, 2018: Free Radical Biology & Medicine
Fateme Akrami-Mohajeri, Zahra Derakhshan, Margherita Ferrante, Negar Hamidiyan, Meysam Soleymani, Gea Oliveri Conti, Roohollah Dehghani Tafti
Listeria monocytogenes is an important foodborne pathogen which its data in Iranian dairy products is limited. A total of 545 samples of traditional dairy products (raw milk, traditional cheese, traditional butter, traditional curd, and traditional ice cream) were collected from traditional dairy shops located in Yazd, Iran. L. monocytogenes was isolated, and positive samples were confirmed by polymerase chain reaction. Antibiotic sensitivity test was conducted to determine the antibiotic resistance. Listeria species were isolated from 11...
April 2018: Food and Chemical Toxicology
Ileana Cocan, Ersilia Alexa, Corina Danciu, Isidora Radulov, Atena Galuscan, Diana Obistioiu, Attila Alexandru Morvay, Renata Maria Sumalan, Mariana-Atena Poiana, Georgeta Pop, Cristina Adriana Dehelean
The current study aimed to investigate ethanolic extracts from the following medicinal plant species cultivated in western Romania: Melissa officinalis L., Rosmarinus officinalis L. (RO) and Salvia officinalis L. (SO). Antioxidant activity, total phenolics content and a profile of the main hydroxycinnamic acids (HCAs), including caffeic, ferulic, coumaric and rosmarinic acids, was determined for each plant extract. The in vitro antimicrobial activity against four bacterial strains ( Escherichia coli , Listeria -, Pseudomonas aeruginosa and Staphylococcus aureus ), and the effect on cell viability in two melanoma cell lines (B164A5 murine melanoma and A375 human melanoma) was also assessed...
February 2018: Experimental and Therapeutic Medicine
M M Gerst, A E Yousef
AIMS: To develop a microassay method to detect antimicrobials produced by spore-forming bacteria, thus speeding up the discovery of new antimicrobials. METHODS AND RESULTS: Environmental isolates were grown in 96-well plates, to allow production of antimicrobial agents, then treated with lysozyme and heated sequentially. Lysozyme heat treatment inhibited or prevented spore-to-cell transformation, thus eliminating interference from spore outgrowth while detecting antimicrobials by indicator bacteria...
February 10, 2018: Journal of Applied Microbiology
Nurul Islam, Jaehyuk Choi, Kwang-Hyun Baek
Endophytes are a potential source of novel bioactive compounds with medicinal properties. In this study, 41 endophytic bacteria (EB) were isolated from tissues of a medicinally important plant Taxus brevifolia (Pacific yew). The objective was to screen all the EB isolates for their antibacterial effects against five foodborne pathogenic bacteria: Bacillus cereus ATCC10876, Staphylococcus aureus ATCC12600, Listeria monocytogenes ATCC19115, Escherichia coli ATCC43890, and Salmonella Typhimurium ATCC19585. Among the EB isolates, T...
January 29, 2018: Foodborne Pathogens and Disease
Cristina Nastasă, Dan C Vodnar, Ioana Ionuţ, Anca Stana, Daniela Benedec, Radu Tamaian, Ovidiu Oniga, Brînduşa Tiperciuc
The global spread of bacterial resistance to drugs used in therapy requires new potent and safe antimicrobial agents. DNA gyrases represent important targets in drug discovery. Schiff bases, thiazole, and triazole derivatives are considered key scaffolds in medicinal chemistry. Fifteen thiazolyl-triazole Schiff bases were evaluated for their antibacterial activity, measuring the growth inhibition zone diameter, the minimum inhibitory concentration (MIC), and the minimum bactericidal concentration (MBC), against Gram-positive ( Staphylococcus aureus , Listeria monocytogenes ) and Gram-negative ( Escherichia coli , Salmonella typhimurium , Pseudomonas aeruginosa ) bacteria...
January 11, 2018: International Journal of Molecular Sciences
Xiaofan Yu, Fang Chen, Ronghui Wang, Yanbin Li
The rapid detection of foodborne pathogens is critical to ensure food safety. The objective of this study is to select aptamers specifically bound to Escherichia coli O157:H7 using the whole-bacterium SELEX (Systematic Evolution of Ligands by Exponential Enrichment) and apply the selected aptamer to a QCM (quartz crystal microbalance) sensor for rapid and sensitive detection of target bacteria. A total of 19 rounds of selection against live E. coli O157:H7 and 6 rounds of counter selection against a mixture of Staphylococcus aureus, Listeria monocytogenes, and Salmonella Typhimurium, were performed...
January 20, 2018: Journal of Biotechnology
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