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  Subjects -> BIOLOGY (Total: 2916 journals)
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MICROBIOLOGY (242 journals)                  1 2     

Showing 1 - 0 of 0 Journals sorted alphabetically
Acta Microbiologica et Immunologica Hungarica     Full-text available via subscription   (Followers: 5)
Addiction Genetics     Open Access   (Followers: 5)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 14)
Advances in Microbiology     Open Access   (Followers: 14)
Advances in Molecular Imaging     Open Access   (Followers: 1)
African Journal of Clinical and Experimental Microbiology     Open Access  
African Journal of Microbiology Research     Open Access   (Followers: 1)
Algorithms for Molecular Biology     Open Access   (Followers: 4)
American Journal of Infectious Diseases and Microbiology     Open Access   (Followers: 14)
American Journal of Microbiological Research     Open Access   (Followers: 1)
American Journal of Microbiology     Open Access   (Followers: 12)
American Journal of Molecular Biology     Open Access   (Followers: 2)
American Journal of Stem Cell Research     Open Access   (Followers: 2)
Annals of Clinical Microbiology and Antimicrobials     Open Access   (Followers: 5)
Annals of Microbiology     Hybrid Journal   (Followers: 6)
Annual Review of Microbiology     Full-text available via subscription   (Followers: 30)
Antimicrobial Agents and Chemotherapy     Hybrid Journal   (Followers: 17)
Applied and Environmental Microbiology     Hybrid Journal   (Followers: 36)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 15)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 53)
Aquatic Microbial Ecology     Hybrid Journal   (Followers: 2)
Archives of Microbiology     Hybrid Journal   (Followers: 7)
Avicenna Journal of Clinical Microbiology and Infection     Open Access   (Followers: 1)
Bangladesh Journal of Medical Microbiology     Open Access  
Beneficial Microbes     Full-text available via subscription   (Followers: 1)
Bio-Research     Full-text available via subscription  
BioArchitecture     Full-text available via subscription  
Biocell     Open Access  
Bioethanol     Open Access  
Biomaterials Science     Full-text available via subscription   (Followers: 6)
BioMolecular Concepts     Hybrid Journal   (Followers: 2)
Biomolecular Detection and Quantification     Open Access  
Biomolecules     Open Access   (Followers: 1)
BMC Microbiology     Open Access   (Followers: 8)
Brazilian Journal of Microbiology     Open Access   (Followers: 2)
Canadian Journal of Infectious Diseases and Medical Microbiology     Open Access   (Followers: 1)
Canadian Journal of Microbiology     Full-text available via subscription   (Followers: 3)
Cell Biology : Research & Therapy     Hybrid Journal   (Followers: 2)
Cell Host & Microbe     Full-text available via subscription   (Followers: 12)
Cell Medicine     Open Access   (Followers: 3)
Cell Regeneration     Open Access   (Followers: 1)
Cell Stem Cell     Full-text available via subscription   (Followers: 26)
CellBio     Open Access  
Cells     Open Access   (Followers: 1)
Cellular & Molecular Immunology     Hybrid Journal   (Followers: 10)
Cellular and Molecular Biology Letters     Open Access   (Followers: 1)
Cellular Microbiology     Hybrid Journal   (Followers: 7)
Cheese: Chemistry, Physics and Microbiology     Full-text available via subscription   (Followers: 2)
Chimerism     Full-text available via subscription  
Clinical Microbiology and Infection     Hybrid Journal   (Followers: 15)
Clinical Microbiology Newsletter     Hybrid Journal   (Followers: 4)
Clinical Microbiology Reviews     Hybrid Journal   (Followers: 14)
Comparative Immunology, Microbiology and Infectious Diseases     Hybrid Journal   (Followers: 10)
Computational Molecular Bioscience     Open Access   (Followers: 1)
Critical Reviews in Microbiology     Hybrid Journal   (Followers: 11)
Current Clinical Microbiology Reports     Hybrid Journal   (Followers: 1)
Current Issues in Molecular Biology     Open Access   (Followers: 2)
Current Microbiology     Hybrid Journal   (Followers: 9)
Current Molecular Biology Reports     Hybrid Journal   (Followers: 1)
Current Molecular Imaging     Hybrid Journal  
Current Opinion in Microbiology     Hybrid Journal   (Followers: 26)
Current Tissue Engineering     Hybrid Journal   (Followers: 1)
Current Topics in Microbiology and Immunology     Hybrid Journal   (Followers: 5)
Diagnostic Microbiology and Infectious Disease     Hybrid Journal   (Followers: 7)
Disease and Molecular Medicine     Open Access   (Followers: 1)
DNA Barcodes     Open Access  
Egyptian Journal of Biochemistry and Molecular Biology     Full-text available via subscription  
Emerging Microbes & Infections     Open Access   (Followers: 2)
Environmental Microbiology     Hybrid Journal   (Followers: 12)
Environmental Microbiology Reports     Hybrid Journal   (Followers: 3)
Enzyme and Microbial Technology     Hybrid Journal   (Followers: 11)
Epigenetics of Degenerative Diseases     Open Access   (Followers: 4)
European Journal of Clinical Microbiology & Infectious Diseases     Hybrid Journal   (Followers: 16)
European Journal of Microbiology and Immunology     Open Access   (Followers: 8)
Experimental and Molecular Pathology     Hybrid Journal   (Followers: 5)
Fems Microbiology Ecology     Hybrid Journal   (Followers: 6)
Fems Microbiology Letters     Hybrid Journal   (Followers: 17)
Fems Microbiology Reviews     Hybrid Journal   (Followers: 21)
Fermentation     Open Access  
Folia Histochemica et Cytobiologica     Open Access  
Folia Microbiologica     Hybrid Journal   (Followers: 1)
Food Microbiology     Hybrid Journal   (Followers: 13)
Frontiers in Cell and Developmental Biology     Open Access   (Followers: 2)
Frontiers in Cellular and Infection Microbiology     Open Access   (Followers: 3)
Frontiers in Cellular Neuroscience     Open Access   (Followers: 3)
Frontiers in Microbiology     Open Access   (Followers: 8)
Frontiers in Molecular Neuroscience     Open Access   (Followers: 1)
Future Microbiology     Full-text available via subscription   (Followers: 3)
Future Virology     Full-text available via subscription   (Followers: 7)
Gene Expression     Full-text available via subscription  
Genetica si Biologie Moleculara     Open Access  
Genetics and Molecular Research     Open Access   (Followers: 3)
Geomicrobiology Journal     Hybrid Journal   (Followers: 2)
Gut Microbes     Full-text available via subscription   (Followers: 7)
IAWA Journal     Hybrid Journal  
Indian Journal of Microbiology     Hybrid Journal   (Followers: 2)
Indian Journal of Pathology and Microbiology     Open Access   (Followers: 1)
Infection Ecology & Epidemiology     Open Access   (Followers: 3)
Inside the Cell     Open Access  
International Journal of Antimicrobial Agents     Hybrid Journal   (Followers: 5)
International Journal of Bacteriology     Open Access  
International Journal of Bioassays     Open Access   (Followers: 2)
International Journal of Biotechnology and Molecular Biology Research     Open Access   (Followers: 2)
International Journal of Food Microbiology     Hybrid Journal   (Followers: 12)
International Journal of Infection and Microbiology     Open Access   (Followers: 1)
International Journal of Medical Microbiology     Hybrid Journal   (Followers: 7)
International Journal of Molecular Medicine     Full-text available via subscription   (Followers: 5)
International Journal of Mycobacteriology     Open Access  
International Journal of Systematic and Evolutionary Microbiology     Full-text available via subscription   (Followers: 3)
International Journal of Virology and Molecular Biology     Open Access  
International Microbiology     Open Access   (Followers: 3)
Invertebrate Immunity     Open Access   (Followers: 1)
JMM Case Reports     Open Access  
Journal of Cell Science & Therapy     Open Access   (Followers: 2)
Journal of Microbial & Biochemical Technology     Open Access   (Followers: 1)
Journal of Applied Biology & Biotechnology     Open Access   (Followers: 1)
Journal of Applied Microbiology     Hybrid Journal   (Followers: 9)
Journal of Basic Microbiology     Hybrid Journal   (Followers: 3)
Journal of Biomolecular Structure and Dynamics     Hybrid Journal   (Followers: 1)
Journal of Bionanoscience     Full-text available via subscription  
Journal of Brewing and Distilling     Open Access  
Journal of Cell Biology and Genetics     Open Access   (Followers: 1)
Journal of Clinical Microbiology     Hybrid Journal   (Followers: 24)
Journal of Clinical Pathology     Full-text available via subscription   (Followers: 12)
Journal of Extracellular Vesicles     Open Access   (Followers: 3)
Journal of Food Microbiology     Open Access   (Followers: 1)
Journal of Genes and Cells     Open Access  
Journal of Global Antimicrobial Resistance     Hybrid Journal   (Followers: 1)
Journal of Histology     Open Access  
Journal of Industrial Microbiology and Biotechnology     Hybrid Journal   (Followers: 10)
Journal of Medical Microbiology     Full-text available via subscription   (Followers: 4)
Journal of Metabonomics & Metabolites     Partially Free   (Followers: 1)
Journal of Microbiological Methods     Hybrid Journal   (Followers: 1)
Journal of Microbiology     Hybrid Journal   (Followers: 7)
Journal of Microbiology and Antimicrobials     Open Access   (Followers: 2)
Journal of Microbiology Research     Open Access   (Followers: 2)
Journal of Micropalaeontology     Hybrid Journal   (Followers: 5)
Journal of Molecular Biochemistry     Open Access   (Followers: 2)
Journal of Molecular Biology Research     Open Access   (Followers: 2)
Journal of Molecular Microbiology and Biotechnology     Full-text available via subscription   (Followers: 12)
Journal of Molecular Pathophysiology     Open Access   (Followers: 1)
Journal of Molecular Psychiatry     Open Access   (Followers: 8)
Journal of Pharmacy & Bioresources     Full-text available via subscription   (Followers: 3)
Journal of Plant Molecular Biology and Biotechnology     Open Access   (Followers: 7)
Journal of Plant Pathology & Microbiology     Open Access  
Journal of Proteome Science and Computational Biology     Open Access  
Journal of Regenerative Medicine and Tissue Engineering     Open Access   (Followers: 1)
Journal of The Academy of Clinical Microbiologists     Open Access  
Journal of the American Society of Brewing Chemists     Full-text available via subscription   (Followers: 1)
Journal of the Institute of Brewing     Free  
Journal of Tropical Microbiology and Biotechnology     Full-text available via subscription  
Jundishapur Journal of Microbiology     Open Access  
Letters In Applied Microbiology     Hybrid Journal   (Followers: 5)
Macrophage     Open Access  
MAP Kinase     Open Access  
Marine Ecology Progress Series MEPS     Hybrid Journal   (Followers: 19)
Medical Mycology     Open Access   (Followers: 3)
Methods in Molecular Biology     Hybrid Journal   (Followers: 16)
Microbes and Health     Open Access   (Followers: 1)
Microbes and Infection     Full-text available via subscription   (Followers: 4)
Microbial Biotechnology     Open Access   (Followers: 4)
Microbial Cell Factories     Open Access   (Followers: 7)
Microbial Drug Resistance     Hybrid Journal   (Followers: 4)
Microbial Ecology     Hybrid Journal   (Followers: 6)
Microbial Ecology in Health and Disease     Open Access  
Microbial Informatics and Experimentation     Open Access   (Followers: 1)
Microbial Pathogenesis     Hybrid Journal   (Followers: 6)
Microbiologia Medica     Open Access   (Followers: 1)
Microbiological Research     Hybrid Journal   (Followers: 6)
Microbiology     Hybrid Journal   (Followers: 12)
Microbiology (SGM)     Full-text available via subscription   (Followers: 16)
Microbiology and Immunology     Hybrid Journal   (Followers: 10)
Microbiology and Molecular Biology Reviews     Hybrid Journal   (Followers: 21)
Microbiology Australia     Hybrid Journal  
Microbiology Discovery     Open Access  
Microbiology Indonesia     Open Access  
Microbiology Research     Open Access   (Followers: 7)
MicrobiologyOpen     Open Access   (Followers: 2)
Microbiome     Hybrid Journal   (Followers: 2)
Microbiome Science and Medicine     Open Access  
Microorganisms     Open Access   (Followers: 2)
MicroRNA     Hybrid Journal   (Followers: 1)
Molecular and Cellular Therapies     Open Access  
Molecular Biology and Genetic Engineering     Open Access  
Molecular Biology Research Communications     Open Access   (Followers: 1)
Molecular Genetics and Metabolism Reports     Open Access   (Followers: 1)
Molecular Genetics, Microbiology and Virology     Hybrid Journal   (Followers: 5)
Molecular Imaging and Biology     Hybrid Journal   (Followers: 2)
Molecular Medicine     Open Access   (Followers: 1)
Molecular Medicine Reports     Full-text available via subscription   (Followers: 4)
Molecular Microbiology     Hybrid Journal   (Followers: 25)
Molecular Oral Microbiology     Partially Free   (Followers: 3)
Molecular Systems Biology     Open Access   (Followers: 9)
Molecular Therapy - Methods & Clinical Development     Open Access  
mSphere     Open Access  
mSystems     Open Access  
Nature Microbiology     Hybrid Journal   (Followers: 4)
Nature Reviews Microbiology     Full-text available via subscription   (Followers: 60)
Neuron Glia Biology     Hybrid Journal  
New Egyptian Journal of Microbiology     Full-text available via subscription  

        1 2     

Journal Cover International Journal of Food Microbiology
  [SJR: 1.614]   [H-I: 121]   [12 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0168-1605
   Published by Elsevier Homepage  [2970 journals]
  • Bifidobacterial inulin-type fructan degradation capacity determines
           cross-feeding interactions between bifidobacteria and Faecalibacterium
           prausnitzii
    • Abstract: Publication date: 16 August 2016
      Source:International Journal of Food Microbiology, Volume 231
      Author(s): Frédéric Moens, Stefan Weckx, Luc De Vuyst
      Prebiotic inulin-type fructans (ITF) display a bifidogenic and butyrogenic effect. Four bifidobacterial strains (Bifidobacterium breve Yakult, Bifidobacterium adolescentis LMG 10734, Bifidobacterium angulatum LMG 11039T, and Bifidobacterium longum subsp. longum LMG 11047), displaying different ITF degradation capacities, were each grown in cocultivation with Faecalibacterium prausnitzii DSM 17677T, an ITF-degrading butyrate-producing colon bacterium, as to unravel their cross-feeding interactions. These coculture fermentations were performed in a medium for colon bacteria, whether or not including acetate (necessary for the growth of F. prausnitzii DSM 17677T and whether or not provided through cross-feeding), supplemented with oligofructose or inulin as the sole energy source. Bifidobacterium breve Yakult did not degrade oligofructose, resulting in the production of high concentrations of butyrate by F. prausnitzii DSM 17677T through oligofructose degradation. The degradation of oligofructose by B. adolescentis LMG 10734 and of oligofructose and inulin by B. angulatum LMG 11039T and B. longum LMG 11047 resulted in the production of acetate, which was cross-fed to F. prausnitzii DSM 17677T, enabling the latter strain to degrade oligofructose and inulin. Slow preferential degradation of the short chain length fractions of oligofructose (intracellularly) by B. adolescentis LMG 10734 enabled substantial oligofructose degradation by F. prausnitzii DSM 17677T. However, fast non-preferential degradation of all chain length fractions of oligofructose (extracellularly) and efficient degradation of the short chain length fractions of inulin by B. angulatum LMG 11039T and B. longum LMG 11047 made it impossible for F. prausnitzii DSM 17677T to compete for the available substrate. These results indicate that cross-feeding interactions between bifidobacteria and acetate-depending, butyrate-producing colon bacteria can be either a pure commensal or beneficial relationship between these bacteria, or can be dominated by competition, depending on the ITF degradation capacities of the bifidobacterial strains involved.


      PubDate: 2016-05-25T18:26:36Z
       
  • High prevalence of extended-spectrum and plasmidic AmpC
           beta-lactamase-producing Escherichia coli from poultry in Tunisia
    • Abstract: Publication date: 16 August 2016
      Source:International Journal of Food Microbiology, Volume 231
      Author(s): Elaa Maamar, Samia Hammami, Carla Andrea Alonso, Nouha Dakhli, Mohamed Salah Abbassi, Sana Ferjani, Zaineb Hamzaoui, Mabrouka Saidani, Carmen Torres, Ilhem Boutiba-Ben Boubaker
      This study was conducted to detect extended spectrum beta-lactamases (ESBLs) and plasmidic AmpC beta-lactamase (pAmpC-BL)-producing Escherichia coli isolates in industrial poultry samples were collected from healthy chickens of the three farms. Samples were inoculated onto desoxycholate-lactose-agar plates supplemented with cefotaxime (2mg/L). E. coli was identified by biochemical and molecular methods and antibiotic susceptibility testing by the disk diffusion method. Genes encoding ESBLs and pAmpC-BL were detected by PCR and sequencing. Phylogenetic groups were determined by triplex PCR. The molecular typing of strains was done by pulsed field gel electrophoresis (PFGE) and Multilocus Sequence Typing (MLST) in those isolates showing different PFGE patterns. Cefotaxime-resistant E. coli isolates were recovered in 48 of 137 fecal samples (35%), and one isolate/sample was further studied. The following beta-lactamase genes were detected: bla CTX-M-1 (29 isolates, isolated in all three farms), bla CTX-M-15 (5 isolates, confined in farm II), bla CTX-M-14 and bla CMY-2 (one isolate and 13 isolates, respectively, in farm III). The 48 cefotaxime-resistant isolates were distributed into phylogroups: B1 (n=21), A (n=15) and D (n=12). PFGE analysis revealed 19 unrelated patterns: 15 different profiles among ESBL-positive strains and 4 among the CMY-2-positive isolates. The following sequence types-associated phylogroups were detected: a) CTX-M-1-positive strains: lineages ST542-B1, ST212-B1, ST58-B1, ST155-B1 and ST349-D; b) CTX-M-15-positive strain: lineage ST405-D; c) CTX-M-14-positive strain: lineage ST1056-B1; d) CMY-2-positive strains: lineages ST117-D, ST2197-A, and ST155-B1. Healthy chickens constitute an important reservoir of ESBL- and pAmpC-BL-producing E. coli isolates that potentially could be transmitted to humans via the food chain or by direct contact.


      PubDate: 2016-05-25T18:26:36Z
       
  • Putrescine production by Lactococcus lactis subsp. cremoris CECT 8666 is
           reduced by NaCl via a decrease in bacterial growth and the repression of
           the genes involved in putrescine production
    • Abstract: Publication date: 2 September 2016
      Source:International Journal of Food Microbiology, Volume 232
      Author(s): Beatriz del Rio, Begoña Redruello, Victor Ladero, Maria Fernandez, Maria Cruz Martin, Miguel A. Alvarez
      The reduction of NaCl in food is a public health priority; high NaCl intakes have been associated with serious health problems. However, it is reported that reducing the NaCl content of cheeses may lead to an increase in the content of biogenic amines (BAs). The present work examines the effect of NaCl on the accumulation of putrescine (one of the BAs often detected at high concentration in cheese) in experimental Cabrales-like cheeses containing Lactococcus lactis subsp. cremoris CECT 8666, a dairy strain that catabolises agmatine to putrescine via the agmatine deiminase (AGDI) pathway. The genes responsible for this pathway are grouped in the AGDI cluster. This comprises a regulatory gene (aguR) (transcribed independently), followed by the catabolic genes that together form an operon (aguBDAC). Reducing the NaCl concentration of the cheese led to increased putrescine accumulation. In contrast, increasing the NaCl concentration of both pH-uncontrolled and pH-controlled (pH 6) cultures of L. lactis subsp. cremoris CECT 8666 significantly inhibited its growth and the production of putrescine. Such production appeared to be inhibited via a reduction in the transcription of the aguBDAC operon; no effect on the transcription of aguR was recorded. The present results suggest that low-sodium cheeses are at risk of accumulating higher concentrations of putrescine.


      PubDate: 2016-05-25T18:26:36Z
       
  • Prevalence and characteristics of verotoxigenic Escherichia coli strains
           isolated from pigs and pork products in Umbria and Marche regions of Italy
           
    • Abstract: Publication date: 2 September 2016
      Source:International Journal of Food Microbiology, Volume 232
      Author(s): Laura Ercoli, Silvana Farneti, Alessia Zicavo, Guerriero Mencaroni, Giuliana Blasi, Gianluca Striano, Stefania Scuota
      In total 1095 samples from 675 pork products, 210 swine colon contents, and 210 swine carcass sponge swabs were collected in Umbria and Marche regions of Italy and examined for the presence of Shiga toxin-producing Escherichia coli (STEC), also known as Verotoxin-producing E. coli (VTEC). After an enrichment step, each sample was analysed by real-time PCR to detect the stx1, stx2, and eae genes. stx-Positive samples were further tested for the “top five” serogroup markers (O157, O26, O103, O111, O145) and cultured onto selective media. The isolates were assigned to stx subtypes and tested for the presence of aaiC and aggR genes. Out of 420 swine samples, 38.6% faecal samples and 13.8% carcass sponge swabs were stx-positive. In total, 33 E. coli STEC isolates were obtained from 30 samples (4 carcasses and 26 colon contents) indicating a culture-positive rate of 7.1%. A higher culture-positive rate was observed in faecal samples (12.4%) than in carcass sponge swabs (1.9%). Out of 675 pork samples, 19 (2.8%) were stx-positive. No STEC strains were isolated from stx-positive pork products. We concluded that STEC isolation from foodstuffs remains difficult, despite the application of ISO/TS 13136:2012. Furthermore, in accordance with the results of studies conducted in other countries, we observed that most of swine STEC strains carried stx 2e gene and lacked of virulence genes, such as eae, aaiC and aggR, indicative of potential pathogenic characteristics for humans. Although the majority of STEC isolates did not express virulence factors correlating with severe human diseases, the association between swine STEC strains and human illness requires further investigations.


      PubDate: 2016-05-25T18:26:36Z
       
  • Non-aflatoxigenic Aspergillus flavus as potential biocontrol agents to
           
    • Abstract: Publication date: 16 August 2016
      Source:International Journal of Food Microbiology, Volume 231
      Author(s): María Silvina Alaniz Zanon, Germán Gustavo Barros, Sofía Noemí Chulze
      Biological control is one of the most promising strategies for preventing aflatoxin contamination in peanuts at field stage. A population of 46 native Aspergillus flavus nonaflatoxin producers were analysed based on phenotypic, physiological and genetic characteristics. Thirty-three isolates were characterized as L strain morphotype, 3 isolates as S strain morphotype, and 10 isolates did not produce sclerotia. Only 11 of 46 non-aflatoxigenic isolates did not produce cyclopiazonic acid. The vegetative compatibility group (VCG) diversity index for the population was 0.37. For field trials we selected the non-aflatoxigenic A. flavus AR27, AR100G and AFCHG2 strains. The efficacy of single and mixed inocula as potential biocontrol agents in Northern Argentina was evaluated through a 2-year study (2014–2015). During the 2014 peanut growing season, most of the treatments reduced the incidence of aflatoxigenic strains in both soil and peanut kernel samples, and no aflatoxin was detected in kernels. During the 2015 growing season, there was a reduction of aflatoxigenic strains in kernel samples from the plots treated with the potential biocontrol agents. Reductions of aflatoxin contamination between 78.36% and 89.55% were observed in treated plots in comparison with the un-inoculated control plots. This study provides the first data on aflatoxin biocontrol based on competitive exclusion in the peanut growing region of Northern Argentina, and proposes bioproducts with potential use as biocontrol agents.


      PubDate: 2016-05-25T18:26:36Z
       
  • Effect of acidic electrolyzed water-induced bacterial inhibition and
           
    • Abstract: Publication date: 16 August 2016
      Source:International Journal of Food Microbiology, Volume 231
      Author(s): Hamzah M. Al-Qadiri, Murad A. Al-Holy, Setareh Ghorban Shiroodi, Mahmoudreza Ovissipour, Byju N. Govindan, Nivin Al-Alami, Shyam S. Sablani, Barbara Rasco
      The effect of acidic electrolyzed water (AEW) on inactivating Escherichia coli O104:H4, Listeria monocytogenes, Aeromonas hydrophila, Vibrio parahaemolyticus and Campylobacter jejuni in laboratory contaminated live clam (Venerupis philippinarum) and mussel (Mytilus edulis) was investigated. The initial levels of bacterial contamination were: in clam 4.9 to 5.7log10 CFU/g, and in mussel 5.1 to 5.5log10 CFU/g. Two types of AEW were used for treatment time intervals of 1 and 2h: strong (SAEW) with an available chlorine concentration (ACC) of 20mg/L, pH=3.1, and an oxidation-reduction potential (ORP) of 1150mV, and weak (WAEW) at ACC of 10mg/L, pH=3.55 and ORP of 950mV. SAEW and WAEW exhibited significant inhibitory activity against inoculated bacteria in both shellfish species with significant differences compared to saline solutions treatments (1–2% NaCl) and untreated controls (0h). SAEW showed the largest inhibitory activity, the extent of reduction (log10 CFU/g) ranged from 1.4–1.7 for E. coli O104:H4; 1.0–1.6 for L. monocytogenes; 1.3–1.6 for A. hydrophila; 1.0–1.5 for V. parahaemolyticus; and 1.5–2.2 for C. jejuni in both types of shellfish. In comparison, significantly (P <0.05) lower inhibitory effect of WAEW was achieved compared to SAEW, where the extent of reduction (log10 CFU/g) ranged from 0.7–1.1 for E. coli O104:H4; 0.6–0.9 for L. monocytogenes; 0.6–1.3 for A. hydrophila; 0.7–1.3 for V. parahaemolyticus; and 0.8–1.9 for C. jejuni in both types of shellfish. Among all bacterial strains examined in this study, AEW induced less bacterial injury (~0.1–1.0log10 CFU/g) and more inactivation effect. This study revealed that AEW (10–20mg/L ACC) could be used to reduce bacterial contamination in live clam and mussel, which may help control possible unhygienic practices during production and processing of shellfish without apparent changes in the quality of the shellfish.


      PubDate: 2016-05-20T18:21:08Z
       
  • ICFMH Announcment
    • Abstract: Publication date: 16 July 2016
      Source:International Journal of Food Microbiology, Volume 229




      PubDate: 2016-05-20T18:21:08Z
       
  • A rapid and highly specific immunofluorescence method to detect
           Escherichia coli O157:H7 in infected meat samples
    • Abstract: Publication date: 16 August 2016
      Source:International Journal of Food Microbiology, Volume 231
      Author(s): Baskar Balakrishnan, Syed Barizuddin, Tumen Wuliji, Majed El-Dweik
      Developing rapid and sensitive methods for the detection of pathogenic Escherichia coli O157:H7 remains a major challenge in food safety. The present study attempts to develop an immunofluorescence technique that uses Protein-A-coated, magnetic beads as the platform. The immunofluorescence technique described here is a direct detection method in which E. coli O157:H7 cells are labeled with tetramethylrhodamine (TRITC) fluorescent dye. TRITC-labeled bacteria are captured by the desired antibody (Ab), which is immobilized on the Protein-A magnetic beads. Fluorescence of the captured cells is recorded in a fluorescence spectrophotometer, where the fluorescence values are shown to be directly proportional to the number of bacteria captured on the immunobead. The formation of an immunocomplex is evidenced by the fluorescence of the beads under microscopy. The Ab immobilization procedure is also evidenced by microscopy using fluorescein isothiocyanate (FITC)-labeled Ab. The total experimental time, including preparation of the sample, is just 1h. The minimum bacterial concentration detected by this method is 1.2±0.06×103 CFUml−1. The high specificity of this method was proved by using the specific monoclonal Ab (MAb) in the test. The proposed protocol was successfully validated with E. coli O157:H7-infected meat samples. This approach also opens the door for the detection of other bacterial pathogens using Protein-A magnetic beads as a detection platform.


      PubDate: 2016-05-20T18:21:08Z
       
  • Editorial Board
    • Abstract: Publication date: 16 July 2016
      Source:International Journal of Food Microbiology, Volume 229




      PubDate: 2016-05-20T18:21:08Z
       
  • Evaluation of the risk of fungal spoilage when substituting sucrose with
           commercial purified Stevia glycosides in sweetened bakery products
    • Abstract: Publication date: 16 August 2016
      Source:International Journal of Food Microbiology, Volume 231
      Author(s): Alicia Rodríguez, Naresh Magan, Angel Medina
      The objectives of this study were to compare the effect of different Stevia-based sugar substitutes (S1–S3), sucrose alone and a mixture of sucrose+S1 on: (a) humectant properties, (b) relative colonisation rates of sponge cake slices at 0.90 aw by strains of Aspergillus flavus, Eurotium amstelodami, Fusarium graminearum and Penicillium verrucosum at 20 and 25°C and (c) shelf-life periods in days prior to visible growth. Results showed that sucrose, S1 commercial sugar substitute and the mixture of sucrose+S1 in water solutions were able to reach water activity levels similar to those of glycerol and glucose mixtures. The S2 and S3 commercial sugar substitutes were unable to reduce aw levels significantly. At 25°C, colonisation of sponge cake slices by E. amstelodami, A. flavus and P. verrucosum occurred in all the treatments. Growth of F. graminearum only occurred on sponge cake slices containing S2 and S3 Stevia-based products at both temperatures. The best control of growth (30days) was achieved in cake slices modified with sucrose or S1 Stevia treatments inoculated with A. flavus and in the sucrose treatment for E. amstelodami at 20°C. F. graminearum growth was completely inhibited when sucrose alone, S1 or sucrose+S1 treatments were used at both temperatures. This study suggests that, as part of a hurdle technology approach, replacing sucrose with low calorie sugar substitutes based on Stevia glycosides needs to be done with care. This is because different products may have variable humectant properties and bulking agents which may shorten the potential shelf-life of intermediate moisture bakery products.


      PubDate: 2016-05-15T23:37:35Z
       
  • Penicillium salamii strain ITEM 15302: A new promising fungal starter for
           salami production
    • Abstract: Publication date: 16 August 2016
      Source:International Journal of Food Microbiology, Volume 231
      Author(s): D. Magistà, M. Ferrara, M.A. Del Nobile, D. Gammariello, A. Conte, G. Perrone
      Traditional sausages are often considered of superior quality to sausages inoculated with commercial starter cultures and this is partially due to the action of the typical house microflora. Penicillium nalgiovense is the species commonly used as starter culture for dry-cured meat production. Recently a new species, Penicillium salamii, was described as typical colonizer during salami seasoning. In order to understand its contribution to the seasoning process, two different experiments on curing of fresh pork sausages were conducted using P. salamii ITEM 15302 in comparison with P. nalgiovense ITEM 15292 at small and industrial scale, and the dry-cured sausages were subjected to sensory analyses. Additionally, proteolytic and lipolytic in vitro assays were performed on both strains. P. salamii ITEM 15302 proved to be a fast growing mould on dry-cured sausage casings, well adapted to the seasoning process, with high lipolytic and proteolytic enzymatic activity that confers typical sensory characteristics to meat products. Therefore, P. salamii ITEM 15302 was shown to be a good candidate as new starter for meat industry.


      PubDate: 2016-05-15T23:37:35Z
       
  • Prevalence and characterization of plasmid-mediated quinolone resistance
           genes in Aeromonas spp. isolated from South African freshwater fish
    • Abstract: Publication date: 16 August 2016
      Source:International Journal of Food Microbiology, Volume 231
      Author(s): Hafizah Yousuf Chenia
      An increasing incidence of multidrug-resistant Aeromonas spp., which are both fish and emerging opportunistic human pathogens, has been observed worldwide. Quinolone–resistant Aeromonas spp. isolates are increasingly being observed in clinical and environmental settings, and this has been attributed primarily to target gene alterations, efflux, and transferable quinolone resistance. Thirty-four Aeromonas spp., obtained from freshwater aquaculture systems, were screened for the presence of GyrA and ParC substitutions, efflux activity and the prevalence of plasmid-mediated quinolone resistance genes, qnr and aac-6′-Ib-cr. Although 44% of isolates were resistant to nalidixic acid, the majority were susceptible to ciprofloxacin and ofloxacin. The predominant GyrA substitution was Ser-83→Val among Aeromonas veronii isolates whilst Aeromonas hydrophila isolates displayed a Ser-83→Ile substitution, and Ser-80→Ile substitutions were observed in ParC. Minimum inhibitory concentrations of fluoro(quinolones) were determined in the presence and absence of the efflux pump inhibitor, phenylalanine-arginine β-naphthylamide (PAβN). Addition of PAβN had no effect on the levels of fluoro(quinolone) resistance observed for these isolates. Although no aac-6′-Ib-cr variant genes were identified, qnrB and qnrS were detected for 41% and 24% of isolates, respectively, by Southern hybridization and confirmed by PCR and sequencing. Quinolone resistance in these fish-associated Aeromonas isolates was related to mutations in the quinolone resistance determining regions of GyrA and ParC and presence of qnrB and qnrS. The presence of qnr alleles in Aeromonas spp. isolates may facilitate high-level fluoroquinolone resistance and potentially serve as reservoirs for the dissemination of qnr genes to other aquatic microbes.


      PubDate: 2016-05-15T23:37:35Z
       
  • Survival and growth of Cronobacter sakazakii on fresh-cut fruit and the
           effect of UV-C illumination and electrolyzed water in the reduction of its
           population
    • Abstract: Publication date: 16 August 2016
      Source:International Journal of Food Microbiology, Volume 231
      Author(s): David Santo, Ana Graça, Carla Nunes, Célia Quintas
      Cronobacter sakazakii, found in foods such as powdered infant formula and plant origin ready-to-eat food, is an opportunistic pathogen to infants, neonates and vulnerable adults. The objective of this study was to monitor the growth of C. sakazakii in fresh-cut ‘Royal gala’ apple, ‘Rocha’ pear, and ‘Piel de sapo’ melon, and the effect of UV-C illumination, acidic electrolyzed water (AEW) and neutral electrolyzed water (NEW) in the reduction of its population. Fresh-cut fruits were inoculated and incubated at different temperatures during 10days while monitoring C. sakazakii. The inhibitory activity of different doses of UV-C (0–10kJ.m2), electrolyzed water and sodium hypochlorite (SH) (100ppm chlorine) was evaluated on the fruits inoculated with C. sakazakii. The bacterium showed a significant growth in the fruits at 12 and 20°C, but did not grow at 4°C, despite having survived for 10days. At 8°C, adaptation phases of 0.6–3.9days were estimated in the fruits before exponential growth. The UV-C 7.5 and 10kJ/m2 produced greater C. sakazakii population decreases (2–2.4logcfu/g) than AEW (1.3–1.8logcfu/g), NEW (1–1.2logcfu/g) and SH (0.8–1.4logcfu/g). The UV-C decontamination system and refrigeration at 4°C, may contribute to the product's safety and quality. The results help better understand the behavior of C. sakazakii on fresh-cut fruit alerting producers of the necessity to respect the high hygienic practices, adequate refrigerating temperature maintenance and caution with the tendency to prolong the validity of this kind of ready-to-eat food.


      PubDate: 2016-05-10T09:50:58Z
       
  • Inactivation of Salmonella, Listeria monocytogenes and Enterococcus
           faecium NRRL B-2354 in a selection of low moisture foods
    • Abstract: Publication date: 16 August 2016
      Source:International Journal of Food Microbiology, Volume 231
      Author(s): Grzegorz Rachon, Walter Peñaloza, Paul A. Gibbs
      The aims of this study were to obtain data on survival and heat resistance of cocktails of Salmonella, Listeria monocytogenes and the surrogate Enterococcus faecium (NRRL B-2354) in four low moisture foods (confectionery formulation, chicken meat powder, pet food and savoury seasoning) during storage before processing. Inoculated samples were stored at 16°C and cell viability examined at day 0, 3, 7 and 21. At each time point, the heat resistance at 80°C was determined. The purpose was to determine a suitable storage time of inoculated foods that can be applied in heat resistance studies or process validations with similar cell viability and heat resistance characteristics. The main inactivation study was carried out within 7days after inoculation, the heat resistance of each bacterial cocktail was evaluated in each low moisture food heated in thermal cells exposed to temperatures between 70 and 140°C. The Weibull model and the first order kinetics (D-value) were used to express inactivation data and calculate the heating time to achieve 5 log reduction at each temperature. Results showed that the pathogens Salmonella and L. monocytogenes and the surrogate E. faecium NRRL B-2354, can survive well (maximum reduction <0.8 log) in low moisture foods maintained at 16°C, as simulation of warehouse raw material storage in winter and before processing. The D80 value of the pathogens and surrogate did not significantly change during the 21day storage (p>0.05). The inactivation kinetics of the pathogens and surrogate at temperatures between 70 and 140°C, were different between each organism and product. E. faecium NRRL B-2354 was a suitable Salmonella surrogate for three of the low moisture foods studied, but not for the sugar-containing confectionery formulation. Heating low moisture food in moisture-tight environments (thermal cells) to 111.2, 105.3 or 111.8°C can inactivate 5 log of Salmonella, L. monocytogenes or E. faecium NRRL B-2354 respectively.


      PubDate: 2016-05-10T09:50:58Z
       
  • Biocontrol of geosmin-producing Streptomyces spp. by two Bacillus strains
           from Chinese liquor
    • Abstract: Publication date: 16 August 2016
      Source:International Journal of Food Microbiology, Volume 231
      Author(s): Yan Zhi, Qun Wu, Hai Du, Yan Xu
      Streptomyces spp. producing geosmin have been regarded as the most frequent and serious microbial contamination causing earthy off-flavor in Chinese liquor. It is therefore necessary to control the Streptomyces community during liquor fermentation. Biological control, using the native microbiota present in liquor making, appears to be a better solution than chemical methods. The objective of this study was to isolate native microbiota antagonistic toward Streptomyces spp. and then to evaluate the possible action mode of the antagonists. Fourteen Bacillus strains isolated from different Daqu (the fermentation starter) showed antagonistic activity against Streptomyces sampsonii, which is one of the dominant geosmin producers. Bacillus subtilis 2–16 and Bacillus amyloliquefaciens 1–45 from Maotai Daqu significantly inhibited the growth of S. sampsonii by 57.8% and 84.3% respectively, and effectively prevented the geosmin production in the simulated fermentation experiments (inoculation ratio 1:1). To probe the biocontrol mode, the ability of strain 2–16 and 1–45 to produce antimicrobial metabolites and to reduce geosmin in the fermentation system was investigated. Antimicrobial substances were identified as lipopeptides by ultra-performance liquid chromatography tandem electrospray ionization/quadrupole-time-of-flight mass spectrometry (UPLC-ESI/Q-TOF MS) and in vitro antibiotic assay. In addition, strains 2–16 and 1–45 were able to remove 45% and 15% of the geosmin respectively in the simulated solid-state fermentation. This study highlighted the potential of biocontrol, and how the use of native Bacillus species in Daqu could provide an eco-friendly method to prevent growth of Streptomyces spp. and geosmin contamination in Chinese liquor fermentation.


      PubDate: 2016-05-10T09:50:58Z
       
  • ICFMH Announcment
    • Abstract: Publication date: 2 July 2016
      Source:International Journal of Food Microbiology, Volume 228




      PubDate: 2016-05-07T08:44:03Z
       
  • An interlaboratory study on efficient detection of Shiga toxin-producing
           Escherichia coli O26, O103, O111, O121, O145, and O157 in food using
           real-time PCR assay and chromogenic agar
    • Abstract: Publication date: 2 August 2016
      Source:International Journal of Food Microbiology, Volume 230
      Author(s): Yukiko Hara-Kudo, Noriko Konishi, Kayoko Ohtsuka, Kaori Iwabuchi, Rie Kikuchi, Junko Isobe, Takumiko Yamazaki, Fumie Suzuki, Yuhki Nagai, Hiroko Yamada, Atsuko Tanouchi, Tetsuya Mori, Hiroshi Nakagawa, Yasufumi Ueda, Jun Terajima
      To establish an efficient detection method for Shiga toxin (Stx)-producing Escherichia coli (STEC) O26, O103, O111, O121, O145, and O157 in food, an interlaboratory study using all the serogroups of detection targets was firstly conducted. We employed a series of tests including enrichment, real-time PCR assays, and concentration by immunomagnetic separation, followed by plating onto selective agar media (IMS-plating methods). This study was particularly focused on the efficiencies of real-time PCR assays in detecting stx and O-antigen genes of the six serogroups and of IMS-plating methods onto selective agar media including chromogenic agar. Ground beef and radish sprouts samples were inoculated with the six STEC serogroups either at 4–6CFU/25g (low levels) or at 22–29CFU/25g (high levels). The sensitivity of stx detection in ground beef at both levels of inoculation with all six STEC serogroups was 100%. The sensitivity of stx detection was also 100% in radish sprouts at high levels of inoculation with all six STEC serogroups, and 66.7%–91.7% at low levels of inoculation. The sensitivity of detection of O-antigen genes was 100% in both ground beef and radish sprouts at high inoculation levels, while at low inoculation levels, it was 95.8%–100% in ground beef and 66.7%–91.7% in radish sprouts. The sensitivity of detection with IMS-plating was either the same or lower than those of the real-time PCR assays targeting stx and O-antigen genes. The relationship between the results of IMS-plating methods and Ct values of real-time PCR assays were firstly analyzed in detail. Ct values in most samples that tested negative in the IMS-plating method were higher than the maximum Ct values in samples that tested positive in the IMS-plating method. This study indicates that all six STEC serogroups in food contaminated with more than 29CFU/25g were detected by real-time PCR assays targeting stx and O-antigen genes and IMS-plating onto selective agar media. Therefore, screening of stx and O-antigen genes followed by isolation of STECs by IMS-plating methods may be an efficient method to detect the six STEC serogroups.


      PubDate: 2016-05-07T08:44:03Z
       
  • Editorial Board
    • Abstract: Publication date: 2 July 2016
      Source:International Journal of Food Microbiology, Volume 228




      PubDate: 2016-05-07T08:44:03Z
       
  • Inhibition of biofilm development and spoilage potential of Shewanella
           baltica by quorum sensing signal in cell-free supernatant from Pseudomonas
           fluorescens
    • Abstract: Publication date: 2 August 2016
      Source:International Journal of Food Microbiology, Volume 230
      Author(s): Aifei Zhao, Junli Zhu, Xiaofeng Ye, Yangyang Ge, Jianrong Li
      The objective of this study was to in vitro evaluate the effect of a cell-free supernatant (CFS) containing quorum sensing (QS) signal of Pseudomonas fluorescens on the growth, biofilm development and spoilage potential of Shewanella baltica, and preliminarily assess the interactive influences of various chemically synthesized autoinducers on spoilage phenotypes of S. baltica. PF01 strain isolated from spoiled Pseudosciaen crocea was identified P. fluorescens. The addition of 25% and 50% CFS to S. baltica culture had no effect on the growth rate during the lag and exponential phase, however, caused cell decline during the stationary phase. The presence of CFS from P. fluorescens significantly inhibited biofilm development, and greatly decreased the production of trimethylamine (TMA) and biogenic amino in S. baltica. Various signal molecules of QS in the CFS of P. fluorescens culture were detected, including seven N-acyl-l-homoserine lactones (AHLs), autoinducer-2 (AI-2) and two diketopiperazines (DKPs). Exogenous supplement of synthesized seven AHLs containing in the CFS decreased biofilm formation and TMA production in S. baltica, while exposure to exogenous cyclo-(l-Pro-l-Leu) was showed to promote spoilage potential, which revealed that S. baltica also sense the two QS molecules. Furthermore, the stimulating effect of cyclo-(l-Pro-l-Leu) was affected when AHL was simultaneously added, suggesting that the inhibitory activity of spoilage phenotypes in S. baltica might be attributed to a competitive effect of these QS compounds in the CFS of P. fluorescens. The present studies provide a good basis for future research on the role of QS in the regulation of spoilage microbial flora.


      PubDate: 2016-05-02T08:36:52Z
       
  • Altered virulence potential of Salmonella Enteritidis cultured in
           different foods: A cumulative effect of differential gene expression and
           immunomodulation
    • Abstract: Publication date: 2 August 2016
      Source:International Journal of Food Microbiology, Volume 230
      Author(s): Sangeeta Jaiswal, Prakash Kumar Sahoo, Daniel Ryan, Jugal Kishore Das, Eesha Chakraborty, Nirmal Kumar Mohakud, Mrutyunjay Suar
      Salmonella enterica serovars Enteritidis (S. Enteritidis) is one of the most common causes of food borne illness. Bacterial growth environment plays an important role in regulating gene expression thereby affecting the virulence profile of the bacteria. Different foods present diverse growth conditions which may affect the pathogenic potential of the bacteria. In the present study, the effect of food environments on the pathogenic potential of S. Enteritidis has been evaluated. S. Enteritidis was grown in different foods e.g. egg white, peanut butter and milk, and virulent phenotypes were compared to those grown in Luria Bertani broth. In-vivo experiments in C57BL/6 mice revealed S. Enteritidis grown in egg white did not induce significant (p <0.001) production of proinflammatory cytokines in mice and were unable to cause colitis despite efficient colonization in cecum, mesenteric lymph node, spleen and liver. Further studies revealed that bacteria grown in LB activated MAP Kinase and NFκB pathways efficiently, while those grown in egg white poorly activated the above pathways which can account for the decreased production of proinflammatory cytokines. qRT PCR analysis revealed SPI-1 effectors were downregulated in bacteria grown in egg white. Interestingly, bacteria grown in egg white showed reversal of phenotype upon change in growth media to LB. Additionally, bacteria grown in milk and peanut butter showed different degrees of virulence in mice as compared to those grown in LB media. Thus, the present study demonstrates that, S. Enteritidis grown in egg white colonizes systemic sites without causing colitis in a mouse model, while bacteria grown in milk and peanut butter show different pathogenicity profiles suggesting that food environments significantly affect the pathogenicity of S. Enteritidis.


      PubDate: 2016-05-02T08:36:52Z
       
  • Predicting outgrowth and inactivation of Clostridium perfringens in meat
           products during low temperature long time heat treatment
    • Abstract: Publication date: 2 August 2016
      Source:International Journal of Food Microbiology, Volume 230
      Author(s): Zhi Duan, Terese Holst Hansen, Tina Beck Hansen, Paw Dalgaard, Susanne Knøchel
      With low temperature long time (LTLT) cooking it can take hours for meat to reach a final core temperature above 53°C and germination followed by growth of Clostridium perfringens is a concern. Available and new growth data in meats including 154 lag times (t lag), 224 maximum specific growth rates (μmax) and 25 maximum population densities (N max) were used to developed a model to predict growth of C. perfringens during the coming-up time of LTLT cooking. New data were generate in 26 challenge tests with chicken (pH6.8) and pork (pH5.6) at two different slowly increasing temperature (SIT) profiles (10°C to 53°C) followed by 53°C in up to 30h in total. Three inoculum types were studied including vegetative cells, non-heated spores and heat activated (75°C, 20min) spores of C. perfringens strain 790-94. Concentrations of vegetative cells in chicken increased 2 to 3logCFU/g during the SIT profiles. Similar results were found for non-heated and heated spores in chicken, whereas in pork C. perfringens 790-94 increased less than 1logCFU/g. At 53°C C. perfringens 790-94 was log-linearly inactivated. Observed and predicted concentrations of C. perfringens, at the time when 53°C (log(N53)) was reached, were used to evaluate the new growth model and three available predictive models previously published for C. perfringens growth during cooling rather than during SIT profiles. Model performance was evaluated by using mean deviation (MD), mean absolute deviation (MAD) and the acceptable simulation zone (ASZ) approach with a zone of ±0.5logCFU/g. The new model showed best performance with MD=0.27logCFU/g, MAD=0.66logCFU/g and ASZ=67%. The two growth models that performed best, were used together with a log-linear inactivation model and D53-values from the present study to simulate the behaviour of C. perfringens under the fast and slow SIT profiles investigated in the present study. Observed and predicted concentrations were compared using a new fail-safe acceptable zone (FSAZ) method. FSAZ was defined as the predicted concentration of C. perfringens plus 0.5logCFU/g. If at least 85% of the observed log-counts were below the FSAZ, the model was considered fail-safe. The two models showed similar performance but none of them performed satisfactorily for all conditions. It is recommended to use the models without a lag phase until more precise lag time models become available.


      PubDate: 2016-04-28T08:29:12Z
       
  • Detection of human adenoviruses in organic fresh produce using molecular
           and cell culture-based methods
    • Abstract: Publication date: 2 August 2016
      Source:International Journal of Food Microbiology, Volume 230
      Author(s): Elisabet Marti, Célia Regina Monte Barardi
      The consumption of organic fresh produce has increased in recent years due to consumer demand for healthy foods without chemical additives. However, the number of foodborne outbreaks associated with fresh produce has also increased. Contamination of food with enteric viruses is a major concern because the viruses have a low infectious dose and high persistence in the environment. Human adenovirus (HAdV) has been proposed as a good marker of faecal contamination. Therefore, the aim of this study was to evaluate the efficiency of the plaque assay (PA), real time PCR (qPCR) and integrated cell culture-RT-qPCR (ICC-RT-qPCR) for the recovery of HAdV from artificially and naturally contaminated fresh produce. Organic lettuce, strawberries and green onions were selected because these fresh products are frequently associated with foodborne outbreaks. The virus extraction efficiencies from artificially contaminated samples varied from 2.8% to 32.8% depending on the food matrix and the quantification method used. Although the HAdV recoveries determined by qPCR were higher than those determined by PA and ICC-RT-qPCR, PA was defined as the most reproducible method. The qPCR assays were more sensitive than the PA and ICC-RT-qPCR assays; however, this technique alone did not provide information about the viability of the pathogen. ICC-RT-qPCR was more sensitive than PA for detecting infectious particles in fresh produce samples. HAdV genome copies were detected in 93.3% of the analysed naturally contaminated samples, attesting to the common faecal contamination of the fresh produce tested. However, only 33.3% of the total samples were positive for infectious HAdV particles based on ICC-RT-qPCR. In conclusion, this study reported that HAdV can be an efficient viral marker for fresh produce contamination. Good detection of infectious HAdV was obtained with the ICC-RT-qPCR and PA assays. Thus, we suggest that the ICC-RT-qPCR and PA assays should be considered when quantitative microbial risk assessment (QMRA) studies are required and to establish reliable food safety guidelines.


      PubDate: 2016-04-28T08:29:12Z
       
  • Pichia kudriavzevii as a representative yeast of North Patagonian
           winemaking terroir
    • Abstract: Publication date: 2 August 2016
      Source:International Journal of Food Microbiology, Volume 230
      Author(s): Silvana M. del Mónaco, María E. Rodríguez, Christian A. Lopes
      Terroir concept includes specific soil, topography, climate, landscape characteristics and biodiversity features. In reference to the last aspect, recent studies investigating the microbial biogeography (lately called ‘microbial terroir’) have revealed that different wine-growing regions maintain different microbial communities. The aim of the present work was to identify potential autochthonous fermentative yeasts isolated from native plants in North Patagonia, Schinus johnstonii, Ephedra ochreata and Lycium chilense, that could be associated to the specific vitivinicultural terroir of this region. Different Pichia kudriavzevii isolates were recovered from these plants and physiologically and genetically compared to regional wine isolates and foreign reference strains of the same species. All isolates were subjected to molecular characterization including mtDNA-RFLP, RAPD-PCR and sequence analysis. Both wine and native P. kudriavzevii isolates from Patagonia showed similar features, different from those showed by foreign strains, suggesting that this species could be part of a specific regional terroir from North Patagonia.


      PubDate: 2016-04-28T08:29:12Z
       
  • Editorial Board
    • Abstract: Publication date: 16 June 2016
      Source:International Journal of Food Microbiology, Volume 227




      PubDate: 2016-04-28T08:29:12Z
       
  • Effect of environmental factors on Fusarium population and associated
           trichothecenes in wheat grain grown in Jiangsu province, China
    • Abstract: Publication date: 2 August 2016
      Source:International Journal of Food Microbiology, Volume 230
      Author(s): Fei Dong, Jianbo Qiu, Jianhong Xu, Mingzheng Yu, Shufang Wang, Yue Sun, Gufeng Zhang, Jianrong Shi
      The present study was performed to identify prevailing Fusarium species and the environmental factors affecting their frequencies and the contamination of grain with major mycotoxins in Jiangsu province. The precipitation levels were 184.2mm, 156.4mm, and 245.8mm in the years 2013–2015, respectively, and the temperature fluctuated by an average of 10.6±7.2°C in 2013, 10.9±7.2°C in 2014, and 10.6±6.3°C in 2015. Co-occurrence of deoxynivalenol (DON), 3-acetyldeoxynivalenol (3ADON), and 15-acetyldeoxynivalenol (15ADON) were observed in wheat. The average concentrations of DON were 879.3±1127.8, 627.8±640.5, and 1628.6±2,168.0μg/kg in 2013–2015, respectively. The average concentrations of 3ADON were 43.5±59.0, 71.2±102.5, and 33.5±111.9μg/kg in 2013–2015, respectively. We found that the average concentration of DON in wheat was positively correlated with precipitation (r =0.998, p <0.01), and 3ADON was negatively correlated with precipitation (r =−0.887, p <0.05). However, there was no correlation between precipitation and 15ADON or nivalenol (NIV). The differences in temperature were not as significant as the differences in rainfall amount over a short time period. Therefore, there were no correlations between temperature and the concentrations of trichothecenes, excluding 3ADON (r =0.996, p <0.01). Our data indicated that Fusarium asiaticum is the primary pathogenic fungus prevalent in the Fusarium head blight disease nursery. The trichothecene chemotype composition differed between Fusarium graminearum sensu stricto (s. str.) and F. asiaticum isolates. The 3ADON chemotype was found only among strains of F. asiaticum. The NIV chemotype was not observed among strains of F. graminearum, while the 15ADON chemotype represented 100% of the F. graminearum strains collected. The results of this study indicated no correlations between environmental conditions and the species or genetic chemotype composition of pathogens in Jiangsu province in 2013–2015.


      PubDate: 2016-04-28T08:29:12Z
       
  • Effect of slaughterhouse and day of sample on the probability of a pig
           carcass being Salmonella-positive according to the Enterobacteriaceae
           count in the largest Brazilian pork production region
    • Abstract: Publication date: 2 July 2016
      Source:International Journal of Food Microbiology, Volume 228
      Author(s): Luís Gustavo Corbellini, Alfredo Bianco Júnior, Eduardo de Freitas Costa, Ana Sofia Ribeiro Duarte, Elenita Ruttscheidt Albuquerque, Jalusa Deon Kich, Marisa Cardoso, Maarten Nauta
      Sources of contamination of carcasses during slaughter include infected pigs as well as environmentally related sources. There are many microbial indicators that can be used in the processing of food to assess food hygiene and the safety of food processing. The presence of some microbial indicators can be viewed as a result of direct or indirect contamination of a food with fecal material. The presence of Enterobacteriaceae is often used as a hygiene indicator, as they are found both in the environment and in the intestine of warm-blooded animals. An association between Salmonella isolation and Enterobacteriaceae count (EC) on pre-chill carcasses has been described, however the impact of slaughterhouse and the day of sampling on the occurrence of Salmonella has not been previously investigated. To this end, mixed logistic regressions (MLRs) with random effects and fixed slopes were performed to assess the change in EC and its correlation with Salmonella occurrence using two data sets. The first describes the EC and Salmonella isolation in 60 pork carcasses in one slaughterhouse sampled at 11 different slaughter steps, including the carcass as a random effect. The second describes the EC and Salmonella isolation on 1150 pre-chill carcasses sampled in 13 slaughterhouses over 230 sampling days, and the model combined two random intercepts, slaughterhouse and date of sampling nested with slaughterhouse (day/slaughterhouse). Statistically significant associations (p <0.0001) between the log of the EC and Salmonella occurrence were found in all models. Nevertheless, although a strong association was found between Enterobacteriaceae and Salmonella contamination in pork carcasses, this association was not constant, given that there was a high variation in the probability of a carcass being positive for Salmonella according to the EC mainly between days of samples. The effect of the day of sampling on Salmonella prevalence was so large that the predictive value of the EC count for Salmonella isolation on a daily basis was compromised. It is possible that on some days batches with a high prevalence of Salmonella carriers shedding a high number of Salmonella were slaughtered. On these days, the potential for contamination/cross-contamination of carcasses will be so large that even hygienic slaughter, confirmed by the low EC on carcasses, will not be able to prevent the presence of Salmonella on some carcasses. The results of this study demonstrate that, despite the statistically significant association found, it may be difficult to predict when hygiene failure measured via EC actually indicates Salmonella contamination, and neither the inverse.


      PubDate: 2016-04-24T08:26:37Z
       
  • Genotype and enterotoxigenicity of Staphylococcus epidermidis isolate from
           ready to eat meat products
    • Abstract: Publication date: 16 July 2016
      Source:International Journal of Food Microbiology, Volume 229
      Author(s): Magdalena Podkowik, Keun Seok Seo, Justyna Schubert, Isaiah Tolo, D. Ashley Robinson, Jacek Bania, Jarosław Bystroń
      We have previously shown that potentially pathogenic isolates of Staphylococcus epidermidis occur at high incidence in ready-to-eat food. Now, within 164 samples of ready-to-eat meat products we identified 32 S. epidermidis isolates. In 8 isolates we detected the genes encoding for staphylococcal enterotoxins, but in 7 S. epidermidis isolates these genes were not stable over passages. One isolate designated 4S was shown to stably harbour sec and sel genes. In the genome sequence of S. epidermidis 4S we identified 21,426-bp region flanked by direct-repeats, encompassing sec and sel genes, corresponding to the previously described composite staphylococcal pathogenicity island (SePI) in S. epidermidis FRI909. Alignment of S. epidermidis 4S and S. epidermidis FRI909 SePIs revealed 6 nucleotide mismatches located in 5 of the total of 29 ORFs. Genomic location of S. epidermidis 4S SePI was the same as in FRI909. S. epidermidis 4S is a single locus variant of ST561, being genetically different from FRI909. SECepi was secreted by S. epidermidis 4S to BHI broth ranging from 14 to almost 36μg/mL, to milk ranging from 6 to 9ng/mL, to beef meat juice from 2 to 3μg/mL and to pork meat juice from 1 to 2μg/mL after 24 and 48h of cultivation, respectively. We provide the first evidence that S. epidermidis occurring in food bears an element encoding an orthologue to Staphylococcus aureus SEC, and that SECepi can be produced in microbial broth, milk and meat juices. Regarding that only enterotoxins produced by S. aureus are officially tracked in food in EU, the ability to produce enterotoxin by S. epidermidis pose real risk for food safety.


      PubDate: 2016-04-24T08:26:37Z
       
  • Effect of electrical field strength applied by PEF processing and storage
           temperature on the outgrowth of yeasts and moulds naturally present in a
           fresh fruit smoothie
    • Abstract: Publication date: 2 August 2016
      Source:International Journal of Food Microbiology, Volume 230
      Author(s): R.A.H. Timmermans, A.L. Nederhoff, M.N. Nierop Groot, M.A.J.S. van Boekel, H.C. Mastwijk
      Pulsed electrical field (PEF) technology offers an alternative to thermal pasteurisation of high-acid fruit juices, by extending the shelf life of food products, while retaining its fresh taste and nutritional value. Substantial research has been performed on the effect of electrical field strength on the inactivation kinetics of spoilage and pathogenic micro-organisms and on the outgrowth of spoilage micro-organisms during shelf life. However, studies on the effect of electrical field strength on the inactivation and outgrowth of surviving populations during shelf life are missing. In this study, we assessed the influence of electrical field strength applied by PEF processing and storage temperature on the outgrowth of surviving yeast and mould populations naturally present in fresh fruit smoothie in time. Therefore, an apple–strawberry–banana smoothie was treated in a continuous-flow PEF system (130L/h), using similar inlet and outlet conditions (preheating temperature 41°C, maximum temperature 58°C) to assure that the amount of energy across the different conditions was kept constant. Smoothies treated with variable electrical field strengths (13.5, 17.0, 20.0 and 24.0kV/cm) were compared to smoothies without treatment for outgrowth of yeasts and moulds. Outgrowth of yeasts and moulds stored at 4°C and 7°C was analysed by plating and visual observation and yeast growth was modelled using the modified logistic growth model (Zwietering model). Results showed that the intensity of the electrical field strength had an influence on the degree of inactivation of yeast cells, resulting in a faster outgrowth over time at lower electrical field strength. Outgrowth of moulds over time was not affected by the intensity of the electrical field strength used. Application of PEF introduces a trade-off between type of spoilage: in untreated smoothie yeasts lead to spoilage after 8days when stored at 4 or 7°C, whereas in PEF treated smoothie yeasts were (partly) inactivated and provided outgrowth opportunities for moulds, which led to spoilage by moulds after 14days (7°C) or 18days (4°C).


      PubDate: 2016-04-24T08:26:37Z
       
  • Phage sensitivity and prophage carriage in Staphylococcus aureus isolated
           from foods in Spain and New Zealand
    • Abstract: Publication date: 2 August 2016
      Source:International Journal of Food Microbiology, Volume 230
      Author(s): Diana Gutiérrez, Lorena Rodríguez-Rubio, Pilar García, Craig Billington, Aruni Premarante, Ana Rodríguez, Beatriz Martínez
      Bacteriophages (phages) are a promising tool for the biocontrol of pathogenic bacteria, including those contaminating food products and causing infectious diseases. However, the success of phage preparations is limited by the host ranges of their constituent phages. The phage resistance/sensitivity profile of eighty seven Staphylococcus aureus strains isolated in Spain and New Zealand from dairy, meat and seafood sources was determined for six phages (Φ11, K, ΦH5, ΦA72, CAPSa1 and CAPSa3). Most of the S. aureus strains were sensitive to phage K (Myoviridae) and CAPSa1 (Siphoviridae) regardless of their origin. There was a higher sensitivity of New Zealand S. aureus strains to phages isolated from both Spain (ΦH5 and ΦA72) and New Zealand (CAPSa1 and CAPSa3). Spanish phages had a higher infectivity on S. aureus strains of Spanish dairy origin, while Spanish strains isolated from other environments were more sensitive to New Zealand phages. Lysogeny was more prevalent in Spanish S. aureus compared to New Zealand strains. A multiplex PCR reaction, which detected ΦH5 and ΦA72 sequences, indicated a high prevalence of these prophages in Spanish S. aureus strains, but were infrequently detected in New Zealand strains. Overall, the correlation between phage resistance and lysogeny in S. aureus strains was found to be weak.


      PubDate: 2016-04-24T08:26:37Z
       
  • Seroprevalence of Toxoplasma gondii and direct genotyping using
           minisequencing in free-range pigs in Burkina Faso
    • Abstract: Publication date: 2 August 2016
      Source:International Journal of Food Microbiology, Volume 230
      Author(s): Sanata Bamba, Lénaïg Halos, Zékiba Tarnagda, Alexandre Alanio, Pauline Macé, Sandrine Moukoury, Ibrahim Sangaré, Robert Guiguemdé, Jean-Marc Costa, Stéphane Bretagne
      Background Swine are a major source of meat for humans. As such, they can play an important role in the epidemiology of human toxoplasmosis. Therefore, we performed an epidemiological study to determine the prevalence and genotypes of Toxoplasma gondii in Burkina Fasan swine. Methods The prevalence of T. gondii infection was evaluated in a 3-month prospective study at the slaughterhouse of Bobo-Dioulasso, Burkina Faso. Anti-Toxoplasma IgG titers were determined on meat juices from pig diaphragms using a commercially available ELISA assay. The DNA was extracted from 25mg of heart biopsies of seropositive animals (IgG ≥50% of the control) and the presence of T. gondii DNA was detected using a quantitative PCR assay. Genotyping was performed directly on DNA from PCR-positive biopsies using high-resolution melting and minisequencing analyses of the repeated B1 gene. Results The prevalence of carcasses positive for anti-Toxoplasma IgG was 29% (87/300) with no difference according to sex and age in contrast to the village of origin (p=0.018). Of the 87 seropositive animals, two were PCR positive (parasitic load at 64 and 128 parasites/mg of heart biopsy). Two new genotypes belonging to Type II and Type III and different from the genotypes previously described using minisequencing were identified. Conclusion Our study provides the first T. gondii seroprevalence data in Burkina Fasan swine. In addition, this direct typing method suggests diversity of the T. gondii genotypes circulating in domestic animals in Burkina Faso. This needs to be confirmed on a wider sampling of subjects.


      PubDate: 2016-04-24T08:26:37Z
       
  • Induction of simultaneous and sequential malolactic fermentation in durian
           wine
    • Abstract: Publication date: 2 August 2016
      Source:International Journal of Food Microbiology, Volume 230
      Author(s): Fransisca Taniasuri, Pin-Rou Lee, Shao-Quan Liu
      This study represented for the first time the impact of malolactic fermentation (MLF) induced by Oenococcus oeni and its inoculation strategies (simultaneous vs. sequential) on the fermentation performance as well as aroma compound profile of durian wine. There was no negative impact of simultaneous inoculation of O. oeni and Saccharomyces cerevisiae on the growth and fermentation kinetics of S. cerevisiae as compared to sequential fermentation. Simultaneous MLF did not lead to an excessive increase in volatile acidity as compared to sequential MLF. The kinetic changes of organic acids (i.e. malic, lactic, succinic, acetic and α-ketoglutaric acids) varied with simultaneous and sequential MLF relative to yeast alone. MLF, regardless of inoculation mode, resulted in higher production of fermentation-derived volatiles as compared to control (alcoholic fermentation only), including esters, volatile fatty acids, and terpenes, except for higher alcohols. Most indigenous volatile sulphur compounds in durian were decreased to trace levels with little differences among the control, simultaneous and sequential MLF. Among the different wines, the wine with simultaneous MLF had higher concentrations of terpenes and acetate esters while sequential MLF had increased concentrations of medium- and long-chain ethyl esters. Relative to alcoholic fermentation only, both simultaneous and sequential MLF reduced acetaldehyde substantially with sequential MLF being more effective. These findings illustrate that MLF is an effective and novel way of modulating the volatile and aroma compound profile of durian wine.


      PubDate: 2016-04-24T08:26:37Z
       
  • Mycotoxin production and predictive modelling kinetics on the growth of
           Aspergillus flavus and Aspergillus parasiticus isolates in whole black
           peppercorns (Piper nigrum L)
    • Abstract: Publication date: 2 July 2016
      Source:International Journal of Food Microbiology, Volume 228
      Author(s): Pratheeba Yogendrarajah, An Vermeulen, Liesbeth Jacxsens, Evangelia Mavromichali, Sarah De Saeger, Bruno De Meulenaer, Frank Devlieghere
      The growth and mycotoxin production of three Aspergillus flavus isolates and an Aspergillus parasiticus isolate were studied in whole black peppercorns (Piper nigrum L.) using a full factorial design with seven water activity (aw) (0.826–0.984) levels and three temperatures (22, 30 and 37°C). Growth rates and lag phases were estimated using linear regression. Diverse secondary models were assessed for their ability to describe the radial growth rate as a function of individual and combined effect of aw and temperature. Optimum radial growth rate ranged from 0.75±0.04 to 2.65±0.02mm/day for A. flavus and 1.77±0.10 to 2.50±0.10mm/day for A. parasiticus based on the Rosso cardinal estimations. Despite the growth failure of some isolates at marginal conditions, all the studied models showed good performance to predict the growth rates. Validation of the models was performed on independently derived data. The bias factors (0.73–1.03), accuracy factors (0.97–1.36) and root mean square error (0.050–0.278) show that the examined models are conservative predictors of the colony growth rate of both fungal species in black peppers. The Rosso cardinal model can be recommended to describe the individual aw effect while the extended Gibson model was the best model for describing the combined effect of aw and temperature on the growth rate of both fungal species in peppercorns. Temperature optimum ranged from 30 to 33°C, while aw optimum was 0.87–0.92 as estimated by multi-factorial cardinal model for both species. The estimated minimum temperature and aw for A. flavus and A. parasiticus for growth were 11–16°C and 0.73–0.76, respectively, hence, achieving these conditions should be considered during storage to prevent the growth of these mycotoxigenic fungal species in black peppercorns. Following the growth study, production of mycotoxins (aflatoxins B1, B2, G1, G2, sterigmatocystin and O-methyl sterigmatocystin (OMST)) was quantified using LC–MS/MS. Very small quantities of AFB1 (<LOQ-9.1μg/kg) were produced only by A. parasiticus. OMST was not produced in any growth conditions by both species. Sterigmatocystin (<LOQ-76.7μg/kg) was the dominant mycotoxin found. High variability in mycotoxin production restricted the modelling of mycotoxin production in black pepper.


      PubDate: 2016-04-20T08:19:04Z
       
  • Letter to the editor on ‘Enhancing vitamin B12 content in soy-yogurt
           by Lactobacillus reuteri, IJFM. 206:56–59’
    • Abstract: Publication date: 2 July 2016
      Source:International Journal of Food Microbiology, Volume 228
      Author(s): Pekka Varmanen, Paulina Deptula, Bhawani Chamlagain, Vieno Piironen



      PubDate: 2016-04-20T08:19:04Z
       
  • Assessing pigmented pericarp of maize kernels as possible source of
           resistance to fusarium ear rot, Fusarium spp. infection and fumonisin
           accumulation
    • Abstract: Publication date: 16 June 2016
      Source:International Journal of Food Microbiology, Volume 227
      Author(s): Giovanni Venturini, Laleh Babazadeh, Paola Casati, Roberto Pilu, Daiana Salomoni, Silvia L. Toffolatti
      One of the purposes of maize genetic improvement is the research of genotypes resistant to fusarium ear rot (FER) and fumonisin accumulation. Flavonoids in the pericarp of the kernels are considered particularly able to reduce the fumonisin accumulation (FUM). The aim of this field study was to assess the effect of flavonoids, associated with anti-insect protection and Fusarium verticillioides inoculation, on FER symptoms and fumonisin contamination in maize kernels. Two isogenic hybrids, one having pigmentation in the pericarp (P1-rr) and the other without it (P1-wr), were compared. P1-rr showed lower values of FER symptoms and FUM contamination than P1-wr only if the anti-insect protection and the F. verticillioides inoculations were applied in combination. Fusarium spp. kernel infection was not influenced by the presence of flavonoids in the pericarp. Artificial F. verticillioides inoculation was more effective than anti-insect protection in enhancing the inhibition activity of flavonoids toward FUM contamination. The interactions between FUM contamination levels and FER ratings were better modeled in the pigmented hybrid than in the unpigmented one. The variable role that the pigment played in kernel defense against FER and FUM indicates that flavonoids alone may not be completely effective in the resistance of fumonisin contamination in maize.


      PubDate: 2016-04-20T08:19:04Z
       
  • Agricultural by-products with bioactive effects: A multivariate approach
           to evaluate microbial and physicochemical changes in a fresh pork sausage
           enriched with phenolic compounds from olive vegetation water
    • Abstract: Publication date: 2 July 2016
      Source:International Journal of Food Microbiology, Volume 228
      Author(s): Luca Fasolato, Lisa Carraro, Pierantonio Facco, Barbara Cardazzo, Stefania Balzan, Agnese Taticchi, Nadia Andrea Andreani, Filomena Montemurro, Maria Elena Martino, Giuseppe Di Lecce, Tullia Gallina Toschi, Enrico Novelli
      The use of phenolic compounds derived from agricultural by-products could be considered as an eco-friendly strategy for food preservation. In this study a purified phenol extract from olive vegetation water (PEOVW) was explored as a potential bioactive ingredient for meat products using Italian fresh sausage as food model. The research was developed in two steps: first, an in vitro delineation of the extract antimicrobial activities was performed, then, the PEOVW was tested in the food model to investigate the possible application in food manufacturing. The in vitro tests showed that PEOVW clearly inhibits the growth of food-borne pathogens such as Listeria monocytogenes and Staphylococcus aureus. The major part of Gram-positive strains was inhibited at the low concentrations (0.375–3mg/mL). In the production of raw sausages, two concentrates of PEOVW (L1: 0.075% and L2: 0.15%) were used taking into account both organoleptic traits and the bactericidal effects. A multivariate statistical approach allowed the definition of the microbial and physicochemical changes of sausages during the shelf life (14days). In general, the inclusion of the L2 concentration reduced the growth of several microbial targets, especially Staphylococcus spp. and LABs (2log10 CFU/g reduction), while the increasing the growth of yeasts was observed. The reduction of microbial growth could be involved in the reduced lipolysis of raw sausages supplemented with PEOVW as highlighted by the lower amount of diacylglycerols. Moisture and aw had a significant effect on the variability of microbiological features, while food matrix (the sausages' environment) can mask the effects of PEOVW on other targets (e.g. Pseudomonas). Moreover, the molecular identification of the main representative taxa collected during the experimentation allowed the evaluation of the effects of phenols on the selection of bacteria. Genetic data suggested a possible strain selection based on storage time and the addition of phenol compounds especially on LABs and Staphylococcus spp. The modulation effects on lipolysis and the reduction of several microbial targets in a naturally contaminated product indicates that PEOVW may be useful as an ingredient in fresh sausages for improving food safety and quality.


      PubDate: 2016-04-20T08:19:04Z
       
  • Extraintestinal pathogenic Escherichia coli sequence type 131 H30-R and
           H30-Rx subclones in retail chicken meat, Italy
    • Abstract: Publication date: 2 July 2016
      Source:International Journal of Food Microbiology, Volume 228
      Author(s): Arash Ghodousi, Celestino Bonura, Paola Di Carlo, Willem B. van Leeuwen, Caterina Mammina
      Extraintestinal pathogenic Escherichia coli sequence type 131 (ST131), typically fluoroquinolone-resistant (FQ-R) and/or extended-spectrum β-lactamase (ESBL)–producing, has emerged globally. Among clinical isolates, ST131, primarily its H30-R and H30-Rx subclones, accounts for most antimicrobial-resistant E. coli and is the dominant E. coli strain worldwide. We assessed its prevalence and characteristics among raw chicken meat samples on sale in Palermo, Italy. A collection of 237 fluoroquinolone resistant and ESBL/AmpC producing E. coli isolates, which had been isolated from processed retail chicken meat in the period May 2013–April 2015, was analyzed. Established polymerase chain reaction methods were used to define ST131 and its H30 subclones, ESBL, AmpC, and plasmid-mediated quinolone resistance (PMQR) determinants. Amplified Fragment Length Polymorphism (AFLP) was performed to assess the relatedness among ST131 isolates. Out of the 237 E. coli isolates, 12 isolates belonged to the phylogenetic group B2. Based on the molecular definition of ExPEC, all isolates were attributed with the status of ExPEC. SNP-PCR results confirmed that nine isolates were ST131. SNP-PCR for H30-R and H30-Rx subclones showed that six and three ExPEC ST131 were positive for H30-R and H30-Rx, respectively. The results of AFLP showed that, except for four isolates grouped into two clusters which proved to be indistinguishable, the isolates under study were genetically heterogeneous. To the best of our knowledge, this is the first report of H30-R and H30-Rx subclones in animal food samples. Our findings appear to support the role of food chain in their transmission to humans.


      PubDate: 2016-04-20T08:19:04Z
       
  • Use of propidium monoazide for selective profiling of viable microbial
           cells during Gouda cheese ripening
    • Abstract: Publication date: 2 July 2016
      Source:International Journal of Food Microbiology, Volume 228
      Author(s): Oylum Erkus, Victor C.L. de Jager, Renske T.C.M. Geene, Ingrid van Alen-Boerrigter, Lucie Hazelwood, Sacha A.F.T. van Hijum, Michiel Kleerebezem, Eddy J. Smid
      DNA based microbial community profiling of food samples is confounded by the presence of DNA derived from membrane compromised (dead or injured) cells. Selective amplification of DNA from viable (intact) fraction of the community by propidium monoazide (PMA) treatment could circumvent this problem. Gouda cheese manufacturing is a proper model to evaluate the use of PMA for selective detection of intact cells since large fraction of membrane compromised cells emerges as a background in the cheese matrix during ripening. In this study, the effect of PMA on cheese community profiles was evaluated throughout manufacturing and ripening using quantitative PCR (qPCR). PMA effectively inhibited the amplification of DNA derived from membrane compromised cells and enhanced the analysis of the intact fraction residing in the cheese samples. Furthermore, a two-step protocol, which involves whole genome amplification (WGA) to enrich the DNA not modified with PMA and subsequent sequencing, was developed for the selective metagenome sequencing of viable fraction in the Gouda cheese microbial community. The metagenome profile of PMA treated cheese sample reflected the viable community profile at that time point in the cheese manufacturing.


      PubDate: 2016-04-20T08:19:04Z
       
  • Characterization and control of Mucor circinelloides spoilage in yogurt
    • Abstract: Publication date: 2 July 2016
      Source:International Journal of Food Microbiology, Volume 228
      Author(s): Abigail B. Snyder, John J. Churey, Randy W. Worobo
      Consumer confidence in the food industry is severely affected by large-scale spoilage incidents. However, relatively little research exists on spoilage potential of members of the fungal subphylum Mucormycotina (e.g. Mucor), which includes dimorphic spoilage organisms that can switch between a yeast-like and hyphal phase depending on environmental conditions. The presence of Mucor circinelloides in yogurt may not cause spoilage, but growth and subsequent changes in quality (e.g. container bloating) can cause spoilage if not controlled. The purpose of this study was to evaluate the effects on M. circinelloides of pasteurization regimen, natamycin concentrations, and storage temperature in yogurt production, as measured by fungal proliferation and carbon dioxide production. A strain of M. circinelloides isolated from commercially spoiled yogurt showed greater yogurt-spoilage potential than clinical isolates and other industrial strains. D-values and z-values were determined for the spoilage isolate in milk as an evaluation of the fungus' ability to survive pasteurization. Natamycin was added to yogurt at 0, 5, 10, 15, and 20ppm (μg/ml) to determine its ability to inhibit M. circinelloides over the course of month-long challenge studies at 4°C, 15°C, and 25°C. Survivors were recovered on acidified PDA and carbon dioxide levels were recorded. The D-values at 54°C, 56°C, and 58°C for hyphae/sporangiospores were (in min) 38.31±0.02, 10.17±0.28, and 1.94±0.53, respectively, which yielded a z-value of 3.09°C. The D-values at 51°C, 53°C, and 55°C for yeast-like cells were (in min) 14.25±0.12, 6.87±1.19, and 2.44±0.35, respectively, which yielded a z-value of 0.34°C. These results indicated that M. circinelloides would not survive fluid milk pasteurization if contamination occurred prior to thermal treatment. CO2 production was only observed when M. circinelloides was incubated under low-oxygen conditions, and occurred only at temperatures above 4°C. Addition of 10ppm and greater of natamycin inhibited the growth and CO2 production of M. circinelloides under moderate temperature abuse when compared to the untreated control. These data suggest that yogurt spoilage (container bloating) caused by anaerobic growth of M. circinelloides is due to post-pasteurization contamination. Temperature abuse facilitated spoilage as CO2 production was observed in yogurt incubated at 15°C and 25°C, but not at 4°C. The addition of at least 10ppm of natamycin prevented M. circinelloides growth in both hyphal and yeast-like phases, as well as CO2 production in temperatures of up to 15°C for 30days.


      PubDate: 2016-04-20T08:19:04Z
       
  • Community dynamics and metabolite target analysis of spontaneous,
           backslopped barley sourdough fermentations under laboratory and bakery
           conditions
    • Abstract: Publication date: 2 July 2016
      Source:International Journal of Food Microbiology, Volume 228
      Author(s): Henning Harth, Simon Van Kerrebroeck, Luc De Vuyst
      Barley flour is not commonly used for baking because of its negative effects on bread dough rheology and loaf volume. However, barley sourdoughs are promising ingredients to produce improved barley-based breads. Spontaneous barley sourdough fermentations were performed through backslopping (every 24h, 10days) under laboratory (fermentors, controlled temperature of 30°C, high dough yield of 400) and bakery conditions (open vessels, ambient temperature of 17–22°C, low dough yield of 200), making use of the same batch of flour. They differed in pH evolution, microbial community dynamics, and lactic acid bacteria (LAB) species composition. After ten backsloppings, the barley sourdoughs were characterized by the presence of the LAB species Lactobacillus fermentum, Lactobacillus plantarum, and Lactobacillus brevis in the case of the laboratory productions (fast pH decrease, pH<4.0 after two backslopping steps), and of Leuconostoc citreum, Leuconostoc mesenteroides, Weissella confusa and Weissella cibaria in the case of the bakery productions (slow pH decrease, pH4.0 after eight backslopping steps). In both sourdough productions, Saccharomyces cerevisiae was the sole yeast species. Breads made with wheat flour supplemented with 20% (on flour basis) barley sourdough displayed a firmer texture, a smaller volume, and an acceptable flavour compared with all wheat-based reference breads. Hence, representative strains of the LAB species mentioned above, adapted to the environmental conditions they will be confronted with, may be selected as starter cultures for the production of stable barley sourdoughs and flavourful breads.


      PubDate: 2016-04-20T08:19:04Z
       
  • Modelling Salmonella transmission among pigs from farm to slaughterhouse:
           Interplay between management variability and epidemiological uncertainty
    • Abstract: Publication date: 16 July 2016
      Source:International Journal of Food Microbiology, Volume 229
      Author(s): Jordi Ferrer Savall, Caroline Bidot, Mily Leblanc-Maridor, Catherine Belloc, Suzanne Touzeau
      Salmonella carriage and cutaneous contamination of pigs at slaughter are a major risk for carcass contamination. They depend on Salmonella prevalence at farm, but also on transmission and skin soiling among pigs during their journey from farm to slaughterhouse. To better understand and potentially control what influences Salmonella transmission within a pig batch during this transport and lairage step, we proposed a compartmental, discrete-time and stochastic model. We calibrated the model using pork chain data from Brittany. We carried out a sensitivity analysis to evaluate the impact of the variability in management protocols and of the uncertainty in epidemiological parameters on three model outcomes: prevalence of infection, average cutaneous contamination and number of new infections at slaughter. Each outcome is mainly influenced by a single management factor: prevalence at slaughter mainly depends on the prevalence at farm, cutaneous contamination on the contamination of lairage pens and new infections on the total duration of transport and lairage. However, these results are strongly affected by the uncertainty in epidemiological parameters. Re-excretion of carriers due to stress does not have a major impact on the number of new infections.


      PubDate: 2016-04-20T08:19:04Z
       
  • Aggregative adherence fimbriae I (AAF/I) mediate colonization of fresh
           produce and abiotic surface by Shiga toxigenic enteroaggregative
           Escherichia coli O104:H4
    • Abstract: Publication date: 16 July 2016
      Source:International Journal of Food Microbiology, Volume 229
      Author(s): Attila Nagy, Yunfeng Xu, Gary R. Bauchan, Daniel R. Shelton, Xiangwu Nou
      The Shiga toxigenic Escherichia coli O104:H4 isolated during the 2011 European outbreak expresses Shiga toxin 2a and possess virulence genes associated with the enteroaggregative E. coli (EAEC) pathotype. It produces plasmid encoded aggregative adherence fimbriae I (AAF/I) which mediate cell aggregation and biofilm formation in human intestine and promote Shiga-toxin adsorption, but it is not clear whether the AAF/I fimbriae are involved in the colonization and biofilm formation on food and environmental matrices such as the surface of fresh produce. We deleted the gene encoding for the AAF/I fimbriae main subunit (AggA) from an outbreak associated E. coli O104:H4 strain, and evaluated the role of AAF/I fimbriae in the adherence and colonization of E. coli O104:H4 to spinach and abiotic surfaces. The deletion of aggA did not affect the adherence of E. coli O104:H4 to these surfaces. However, it severely diminished the colonization and biofilm formation of E. coli O104:H4 on these surfaces. Strong aggregation and biofilm formation on spinach and abiotic surfaces were observed with the wild type strain but not the isogenic aggA deletion mutant, suggesting that AAF/I fimbriae play a crucial role in persistence of O104:H4 cells outside of the intestines of host species, such as on the surface of fresh produce.


      PubDate: 2016-04-20T08:19:04Z
       
  • Evaluation of viability PCR performance for assessing norovirus
           infectivity in fresh-cut vegetables and irrigation water
    • Abstract: Publication date: 16 July 2016
      Source:International Journal of Food Microbiology, Volume 229
      Author(s): W. Randazzo, Francisco López-Gálvez, A. Allende, R. Aznar, G. Sánchez
      Norovirus (NoV) detection in food and water is mainly carried out by quantitative RT-PCR (RT-qPCR). The inability to differentiate between infectious and inactivated viruses and the resulting overestimation of viral targets is considered a major disadvantage of RT-qPCR. Initially, conventional photoactivatable dyes (i.e. propidium monoazide, PMA and ethidium monoazide, EMA) and newly developed ones (i.e. PMAxx and PEMAX) were evaluated for the discrimination between infectious and thermally inactivated NoV genogroup I (GI) and II (GII) suspensions. Results showed that PMAxx was the best photoactivatable dye to assess NoV infectivity. This procedure was further optimized in artificially inoculated lettuce. Pretreatment with 50μM PMAxx and 0.5% Triton X-100 (Triton) for 10min reduced the signal of thermally inactivated NoV by ca. 1.8 logs for both genogroups in lettuce concentrates. Additionally, this pretreatment reduced the signal of thermally inactivated NoV GI between 1.4 and 1.9 logs in spinach and romaine and lamb's lettuces and by >2 logs for NoV GII in romaine and lamb's lettuce samples. Moreover this pretreatment was satisfactorily applied to naturally-contaminated water samples with NoV GI and GII. Based on the obtained results this pretreatment has the potential to be integrated in routine diagnoses to improve the interpretation of positive NoV results obtained by RT-qPCR.


      PubDate: 2016-04-20T08:19:04Z
       
  • Inhibitory effects of grape seed extract on growth, quorum sensing, and
           virulence factors of CDC “top-six” non-O157 Shiga toxin
           producing E. coli
    • Abstract: Publication date: 16 July 2016
      Source:International Journal of Food Microbiology, Volume 229
      Author(s): L. Sheng, S.A. Olsen, J. Hu, W. Yue, W.J. Means, M.J. Zhu
      Non-O157 Shiga toxin producing Escherichia coli (STECs) have become a growing concern to the food industry. Grape seed extract (GSE), a byproduct of wine industry, is abundant in polyphenols that are known to be beneficial to health. The objective of this study was to evaluate the effect of GSE on the growth, quorum sensing, and virulence factors of Centers for Disease Control and Prevention (CDC) “top-six” non-O157 STECs. Minimal inhibitory concentration (MIC) of GSE was 2mg/ml against E. coli O26:H11, and 4mg/ml against the other non-O157 STECs tested. Minimal bactericidal concentration (MBC) was the same as MIC for all six non-O157 STECs tested. At 5×105 CFU/ml inoculation level, 4mg/ml GSE effectively inhibited the growth of all tested strains, while 0.25–2mg/ml GSE delayed bacterial growth. At a higher inoculation level (1×107 CFU/ml), GSE had less efficacy against the growth of the selected six non-O157 STECs. Its impact on bacterial virulence was then assessed at this inoculation level. Autoinducer-2 (AI-2) is a universal signal molecule mediating quorum sensing (QS). GSE at concentration as low as 0.5mg/ml dramatically reduced AI-2 production of all non-O157 STECs tested, with the inhibitory effect proportional to GSE levels. Consistent with diminished QS, GSE at concentration of 0.125mg/ml caused marked reduction of swimming motility of all motile non-O157 STECs tested. In agreement, GSE treatment reduced the production of flagella protein FliC and its regulator FliA in E. coli O103:H2 and E. coli O111:H2. Furthermore, 4mg/ml GSE inhibited the production of Shiga toxin, a major virulence factor, in E. coli O103:H2 and E. coli O111:H2. In summary, GSE inhibits the growth of “top-six” non-O157 STECs at the population level relevant to food contamination. At higher initial population, GSE suppresses QS with concomitant decrease in motility, flagella protein expression and Shiga toxin production. Thus, GSE has the potential to be used in food industry to control non-O157 STEC.


      PubDate: 2016-04-20T08:19:04Z
       
  • Effect of relevant environmental stresses on survival of enterohemorrhagic
           Escherichia coli in dry-fermented sausage
    • Abstract: Publication date: 16 July 2016
      Source:International Journal of Food Microbiology, Volume 229
      Author(s): Anette McLeod, Ingrid Måge, Even Heir, Lars Axelsson, Askild L. Holck
      Dry-fermented sausages (DFSs) have been linked to several serious foodborne outbreaks of enterohemorrhagic Escherichia coli (EHEC). The ability of pathogens to utilize adaptive responses to different stressful conditions intended to control their growth in foods, food preparation and production processes may enhance their survival. In certain cases, induced tolerance to one type of stress may lead to enhanced resistance to the applied stress as well as to other stresses. We exposed two EHEC strains, MF3582 of serotype O157:H− and MF5554 of serogroup O145, to different stresses commonly encountered during a production process. The two EHEC strains, previously shown to have different abilities to survive DFS production process conditions, were subjected to low temperatures (4°C and 12°C), 5% NaCl or 1% lactic acid for 6days prior to being added to sausage batters. Survival of EHEC was recorded in salami of two recipes, fermented at two temperatures (20°C and 30°C). The results showed that recipe type had the largest impact on EHEC reductions where Moderate recipe (MR) salami batters containing increased levels of NaCl, glucose and NaNO2 provided enhanced EHEC reductions in salami (2.6 log10) compared to Standard recipe (SR) salami (1.7 log10). Effects of pre-exposure stresses were dependent both on strain and recipe. While acid adaptation of MF5554 provided enhanced log10 reductions from 2.0 to 3.0 in MR sausages, adaptation to a combination of acid and salt stress showed the opposite effect in SR sausages with reductions of only 1.1 log10 as compared to the average of 1.8 log10 for the other SR sausages. Otherwise, the salt and acid adaptation single stresses had relatively small effects on EHEC survival through the DFS production process and subsequent storage and freeze/thaw treatments. Growing cells and cells frozen in batter survived poorly in MR sausages with an average reduction of 3.4 and 3.2 log10, respectively. The reductions of EHEC after storage of DFS increased with higher temperature and storage time. Up to 3.7 log10 additional reduction was obtained when MF3582 was stored for 2months at 20°C. In conclusion, adaptation of EHEC to acid, salt and low temperatures prior to being introduced in a DFS production process has limited, but strain dependent effects on EHEC reductions. Producers should avoid conditions leading to acid and salt adapted cells that can contaminate the sausage batter. Recipe parameters had the largest impact on EHEC reductions while storage at 20°C is effective for enhanced reductions in finished products.


      PubDate: 2016-04-20T08:19:04Z
       
  • Enhancing the antibacterial efficacy of isoeugenol by emulsion
           encapsulation
    • Abstract: Publication date: 16 July 2016
      Source:International Journal of Food Microbiology, Volume 229
      Author(s): Christina Krogsgård Nielsen, Jørgen Kjems, Tina Mygind, Torben Snabe, Karin Schwarz, Yvonne Serfert, Rikke Louise Meyer
      Food spoilage and foodborne illnesses are two global challenges for food manufacturers. Essential oils are natural antibacterials that could have a potential for use in food preservation. Unfortunately high concentrations are needed to obtain the desired antibacterial effect, and this limits their use in food due to their adverse organoleptic properties. Encapsulation could make essential oils more effective by concentrating them in the aqueous phase of the food matrix where the bacteria are present. Here we tested encapsulation of the essential oil isoeugenol in spray-dried emulsions as a means of making isoeugenol a more effective antibacterial for use in food preservation. We used β-lactoglobulin and n-OSA starch as emulsifiers, and some emulsions were coated with positively charged chitosan to promote the contact with bacteria through electrostatic interactions. The antibacterial efficacy was quantified as the minimal bactericidal concentration in growth media, milk and carrot juice. The emulsion encapsulation system developed in this study provided high loading capacities, and encapsulation enhanced the efficacy of isoeugenol against Gram-positive and -negative bacteria in media and carrot juice but not in milk. Chitosan-coating did not enhance the efficacy further, possibly due to the aggregation of the chitosan-coated emulsions. The encapsulation system is easy to upscale and should be applicable for encapsulation of similar essential oils. Therefore, we believe it has potential to be used for natural food preservation.


      PubDate: 2016-04-20T08:19:04Z
       
  • Modeling the survival kinetics of Salmonella in tree nuts for use in risk
           assessment
    • Abstract: Publication date: 16 June 2016
      Source:International Journal of Food Microbiology, Volume 227
      Author(s): Sofia M. Santillana Farakos, Régis Pouillot, Nathan Anderson, Rhoma Johnson, Insook Son, Jane Van Doren
      Salmonella has been shown to survive in tree nuts over long periods of time. This survival capacity and its variability are key elements for risk assessment of Salmonella in tree nuts. The aim of this study was to develop a mathematical model to predict survival of Salmonella in tree nuts at ambient storage temperatures that considers variability and uncertainty separately and can easily be incorporated into a risk assessment model. Data on Salmonella survival on raw almonds, pecans, pistachios and walnuts were collected from the peer reviewed literature. The Weibull model was chosen as the baseline model and various fixed effect and mixed effect models were fit to the data. The best model identified through statistical analysis testing was then used to develop a hierarchical Bayesian model. Salmonella in tree nuts showed slow declines at temperatures ranging from 21°C to 24°C. A high degree of variability in survival was observed across tree nut studies reported in the literature. Statistical analysis results indicated that the best applicable model was a mixed effect model that included a fixed and random variation of δ per tree nut (which is the time it takes for the first log10 reduction) and a fixed variation of ρ per tree nut (parameter which defines the shape of the curve). Higher estimated survival rates (δ) were obtained for Salmonella on pistachios, followed in decreasing order by pecans, almonds and walnuts. The posterior distributions obtained from Bayesian inference were used to estimate the variability in the log10 decrease levels in survival for each tree nut, and the uncertainty of these estimates. These modeled uncertainty and variability distributions of the estimates can be used to obtain a complete exposure assessment of Salmonella in tree nuts when including time–temperature parameters for storage and consumption data. The statistical approach presented in this study may be applied to any studies that aim to develop predictive models to be implemented in a probabilistic exposure assessment or a quantitative microbial risk assessment.


      PubDate: 2016-04-09T13:02:23Z
       
  • Study of gene expression and OTA production by Penicillium nordicum during
           a small-scale seasoning process of salami
    • Abstract: Publication date: 16 June 2016
      Source:International Journal of Food Microbiology, Volume 227
      Author(s): Massimo Ferrara, Donato Magistà, Filomena Epifani, Salvatore Cervellieri, Vincenzo Lippolis, Antonia Gallo, Giancarlo Perrone, Antonia Susca
      Penicillium nordicum, an important and consistent producer of ochratoxin A (OTA), is a widely distributed contaminant of protein rich food with elevated NaCl. It is usually found on dry-cured meat products and is considered the main species responsible for their contamination by OTA. The aim of this work was to study the gene expression of a polyketide synthase (otapksPN) involved in P. nordicum OTA biosynthesis, and OTA production during a small-scale seasoning process. Fresh pork sausages were surface inoculated with P. nordicum and seasoned for 30days. Gene expression and OTA production were monitored throughout the seasoning process after 4, 5, 6, 7, 10, 14, and 30days. The expression of otapksPN gene was already detected after 4days and increased significantly after 7days of seasoning, reaching the maximum expression level after 10days (1.69×104 copies/100mg). Consistently with gene expression monitoring, OTA was detected from the 4th day and its content increased significantly from the 7th day, reaching the maximum level after 10days. In the late stages of the seasoning process, OTA did not increase further and the number of gene copies was progressively reduced after 14 and 30days.


      PubDate: 2016-04-07T13:02:18Z
       
  • Variations in grain lipophilic phytochemicals, proteins and resistance to
           Fusarium spp. growth during grain storage as affected by biological plant
           protection with Aureobasidium pullulans (de Bary)
    • Abstract: Publication date: 16 June 2016
      Source:International Journal of Food Microbiology, Volume 227
      Author(s): Urszula Wachowska, Małgorzata Tańska, Iwona Konopka
      Modern agriculture relies on an integrated approach, where chemical treatment is reduced to a minimum and replaced by biological control that involves the use of active microorganisms. The effect of the antagonistic yeast-like fungus Aureobasidium pullulans on proteins and bioactive compounds (alkylresorcinols, sterols, tocols and carotenoids) in winter wheat grain and on the colonization of wheat kernels by fungal microbiota, mainly Fusarium spp. pathogens, was investigated. Biological treatment contributed to a slight increase contents of tocols, alkylresorcinols and sterols in grain. At the same time, the variation of wheat grain proteins was low and not significant. Application of A. pullulans enhanced the natural yeast colonization after six months of grain storage and inhibited growth of F. culmorum pathogens penetrating wheat kernel. This study demonstrated that an integrated approach of wheat grain protection with the use of the yeast-like fungus A. pullulans reduced kernel colonization by Fusarium spp. pathogens and increased the content of nutritionally beneficial phytochemicals in wheat grain without a loss of gluten proteins responsible for baking value.


      PubDate: 2016-04-07T13:02:18Z
       
  • Antimicrobial susceptibility of Clostridium difficile isolated from food
           animals on farms
    • Abstract: Publication date: 16 June 2016
      Source:International Journal of Food Microbiology, Volume 227
      Author(s): S.N. Thitaram, J.F. Frank, G.R. Siragusa, J.S. Bailey, D.A. Dargatz, J.E. Lombard, C.A. Haley, S.A. Lyon, P.J. Fedorka-Cray
      Clostridium difficile is commonly associated with a spectrum of disease in humans referred to as C. difficile-associated disease (CDAD) and use of antimicrobials is considered a risk factor for development of disease in humans. C. difficile can also inhabit healthy food animals and transmission to humans is possible. As a result of the complexity and cost of testing, C. difficile is rarely tested for antimicrobial susceptibility. A total of 376 C. difficile strains (94 each from swine and dairy feces, and 188 from beef cattle feces) were isolated from healthy food animals on farms during studies conducted by the National Animal Health Monitoring System. Using the Etest (AB Biodisk, Solna, Sweden), samples were tested for susceptibility to nine antimicrobials implicated as risk factors for CDAD (linezolid, amoxicillin-clavulanic acid, ampicillin, clindamycin, erythromycin, levofloxacin, metronidazole, rifampicin, and vancomycin). Vancomycin was active against all isolates of C. difficile (MIC90 =3.0μg/ml) while almost all isolates (n=369; 98.1%) were resistant to levofloxacin. With the exception of vancomycin, resistance varied by animal species as follows: linezolid (8.5% resistance among swine versus 2.1 and 1.1% resistance among dairy and beef, respectively), clindamycin (56.4% resistance among swine versus 80% and 90.9% resistance among dairy and beef, respectively), and rifampicin (2.1% and 0% resistance among swine and dairy cattle isolates, respectively versus 14.3% resistance among beef isolates). Regardless of species, multiple drug resistance was observed most often to combinations of clindamycin and levofloxacin (n=195; 51.9%) and ampicillin, clindamycin and levofloxacin (n=41; 10.9%). The reason for the variability of resistance between animal species is unknown and requires further research.


      PubDate: 2016-04-03T13:02:07Z
       
  • Growth and aggressiveness factors affecting Monilinia spp. survival
           peaches
    • Abstract: Publication date: Available online 28 March 2016
      Source:International Journal of Food Microbiology
      Author(s): M. Villarino, P. Melgarejo, A. De Cal
      Brown rot of stone fruit is caused by three species of Monilinia, Monilinia laxa, M. fructigena, and M. fructicola. Eleven components of 20 different isolates of each of the three Monilinia species were analyzed to determine distinct aggressiveness and growth characteristics among the three fungi. M. fructicola showed the greatest lesion diameter, and the lowest incubation and latency period on fruit postharvest, however isolates of M. fructigena exhibited less aggressiveness components. Five growth characteristics of M. fructicola could be used to distinguish M. fructicola from the other two species. The dendrogram generated from only the presence of sclerotia and lesion length on infected fruit separated the 60 isolates into two clusters (r =0.93). One cluster was composed of the M. laxa and M. fructigena isolates and the other cluster comprised the M. fructicola isolates. However, the dendrogram generated based on the presence of stromata and sclerotia in the same colony of the three species when they were grown on potato dextrose agar, and the lesion diameter on fruit infected with each species separated the 60 isolates into three clusters (r =0.81). Each cluster comprised the isolates of each of three Monilinia spp. We discussed the effect of M. fructicola growth and aggressiveness differences on the displacement of M. laxa and M. fructigena by M. fructicola recorded in Spanish peach orchards and their effect on brown rot at postharvest.


      PubDate: 2016-03-30T13:00:47Z
       
 
 
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