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MICROBIOLOGY (254 journals)                  1 2 | Last

Showing 1 - 200 of 254 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: 21)
Advances in Microbiology     Open Access   (Followers: 20)
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: 18)
American Journal of Microbiological Research     Open Access   (Followers: 2)
American Journal of Microbiology     Open Access   (Followers: 14)
American Journal of Molecular Biology     Open Access   (Followers: 3)
American Journal of Stem Cell Research     Open Access   (Followers: 3)
Annals of Clinical Microbiology and Antimicrobials     Open Access   (Followers: 7)
Annals of Microbiology     Hybrid Journal   (Followers: 9)
Annual Review of Microbiology     Full-text available via subscription   (Followers: 37)
Antimicrobial Agents and Chemotherapy     Hybrid Journal   (Followers: 22)
Antiviral Research     Hybrid Journal   (Followers: 7)
Applied and Environmental Microbiology     Hybrid Journal   (Followers: 44)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 17)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 61)
Aquatic Microbial Ecology     Hybrid Journal   (Followers: 2)
Archives of Microbiology     Hybrid Journal   (Followers: 8)
Avicenna Journal of Clinical Microbiology and Infection     Open Access   (Followers: 1)
Bangladesh Journal of Medical Microbiology     Open Access   (Followers: 1)
Beneficial Microbes     Full-text available via subscription   (Followers: 2)
Bio-Research     Full-text available via subscription   (Followers: 1)
BioArchitecture     Full-text available via subscription  
Bioethanol     Open Access  
Biomaterials Science     Full-text available via subscription   (Followers: 9)
BioMolecular Concepts     Hybrid Journal   (Followers: 2)
Biomolecular Detection and Quantification     Open Access  
Biomolecules     Open Access   (Followers: 1)
Biotechnology and Molecular Biology Reviews     Open Access   (Followers: 1)
BMC Microbiology     Open Access   (Followers: 11)
Brazilian Journal of Microbiology     Open Access   (Followers: 2)
Canadian Journal of Infectious Diseases and Medical Microbiology     Open Access   (Followers: 3)
Canadian Journal of Microbiology     Full-text available via subscription   (Followers: 4)
Cell Biology : Research & Therapy     Hybrid Journal   (Followers: 3)
Cell Host & Microbe     Full-text available via subscription   (Followers: 16)
Cell Medicine     Open Access   (Followers: 3)
Cell Regeneration     Open Access   (Followers: 1)
Cell Stem Cell     Full-text available via subscription   (Followers: 31)
CellBio     Open Access  
Cells     Open Access   (Followers: 2)
Cellular & Molecular Immunology     Hybrid Journal   (Followers: 12)
Cellular and Molecular Biology Letters     Open Access   (Followers: 1)
Cellular and Molecular Life Sciences (CMLS)     Hybrid Journal   (Followers: 6)
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: 18)
Clinical Microbiology Newsletter     Hybrid Journal   (Followers: 6)
Clinical Microbiology Reviews     Hybrid Journal   (Followers: 17)
Comparative Immunology, Microbiology and Infectious Diseases     Hybrid Journal   (Followers: 11)
Computational Molecular Bioscience     Open Access   (Followers: 2)
Critical Reviews in Microbiology     Hybrid Journal   (Followers: 12)
Current Clinical Microbiology Reports     Hybrid Journal   (Followers: 1)
Current Issues in Molecular Biology     Open Access   (Followers: 2)
Current Microbiology     Hybrid Journal   (Followers: 11)
Current Molecular Biology Reports     Hybrid Journal   (Followers: 1)
Current Molecular Imaging     Hybrid Journal  
Current Opinion in Microbiology     Hybrid Journal   (Followers: 31)
Current Tissue Engineering     Hybrid Journal   (Followers: 2)
Current Topics in Microbiology and Immunology     Hybrid Journal   (Followers: 11)
Diagnostic Microbiology and Infectious Disease     Hybrid Journal   (Followers: 8)
DNA Barcodes     Open Access  
Egyptian Journal of Biochemistry and Molecular Biology     Full-text available via subscription  
Emerging Microbes & Infections     Open Access   (Followers: 3)
Environmental Microbiology     Hybrid Journal   (Followers: 16)
Environmental Microbiology Reports     Hybrid Journal   (Followers: 4)
Enzyme and Microbial Technology     Hybrid Journal   (Followers: 14)
Epigenetics of Degenerative Diseases     Open Access   (Followers: 5)
European Journal of Clinical Microbiology & Infectious Diseases     Hybrid Journal   (Followers: 18)
European Journal of Microbiology and Immunology     Open Access   (Followers: 8)
Experimental and Molecular Pathology     Hybrid Journal   (Followers: 4)
Experimental Cell Research     Hybrid Journal   (Followers: 6)
Fems Microbiology Ecology     Hybrid Journal   (Followers: 9)
Fems Microbiology Letters     Hybrid Journal   (Followers: 20)
Fems Microbiology Reviews     Hybrid Journal   (Followers: 25)
Fermentation     Open Access   (Followers: 1)
Folia Histochemica et Cytobiologica     Open Access  
Folia Microbiologica     Hybrid Journal   (Followers: 1)
Food Microbiology     Hybrid Journal   (Followers: 16)
Frontiers in Cell and Developmental Biology     Open Access   (Followers: 4)
Frontiers in Cellular and Infection Microbiology     Open Access   (Followers: 3)
Frontiers in Cellular Neuroscience     Open Access   (Followers: 8)
Frontiers in Microbiology     Open Access   (Followers: 10)
Frontiers in Molecular Neuroscience     Open Access   (Followers: 4)
Future Microbiology     Hybrid Journal   (Followers: 4)
Future Virology     Hybrid Journal   (Followers: 8)
Gene Expression     Full-text available via subscription  
Genetica si Biologie Moleculara     Open Access  
Genetics and Molecular Research     Open Access   (Followers: 4)
Geomicrobiology Journal     Hybrid Journal   (Followers: 3)
Gut Microbes     Full-text available via subscription   (Followers: 8)
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: 7)
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 Genetics and Molecular Biology     Open Access  
International Journal of Infection and Microbiology     Open Access   (Followers: 1)
International Journal of Medical Microbiology     Hybrid Journal   (Followers: 8)
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: 4)
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: 2)
Journal of Applied Biology & Biotechnology     Open Access   (Followers: 2)
Journal of Applied Microbiology     Hybrid Journal   (Followers: 14)
Journal of Bacteriology     Hybrid Journal   (Followers: 29)
Journal of Basic Microbiology     Hybrid Journal   (Followers: 3)
Journal of Biomolecular Structure and Dynamics     Hybrid Journal   (Followers: 2)
Journal of Bionanoscience     Full-text available via subscription  
Journal of Bone Marrow Research     Open Access   (Followers: 2)
Journal of Brewing and Distilling     Open Access   (Followers: 2)
Journal of Cell and Animal Biology     Open Access  
Journal of Cell Biology and Genetics     Open Access   (Followers: 2)
Journal of Clinical Microbiology     Hybrid Journal   (Followers: 30)
Journal of Clinical Pathology     Full-text available via subscription   (Followers: 10)
Journal of Extracellular Vesicles     Open Access   (Followers: 4)
Journal of Food Microbiology     Open Access   (Followers: 4)
Journal of General and Molecular Virology     Open Access   (Followers: 1)
Journal of Genes and Cells     Open Access  
Journal of Global Antimicrobial Resistance     Hybrid Journal   (Followers: 2)
Journal of Industrial Microbiology and Biotechnology     Hybrid Journal   (Followers: 15)
Journal of Medical Microbiology     Full-text available via subscription   (Followers: 4)
Journal of Microbiological Methods     Hybrid Journal   (Followers: 2)
Journal of Microbiology     Hybrid Journal   (Followers: 8)
Journal of Microbiology and Antimicrobials     Open Access   (Followers: 2)
Journal of Microbiology Research     Open Access   (Followers: 4)
Journal of Micropalaeontology     Hybrid Journal   (Followers: 7)
Journal of Molecular Biochemistry     Open Access   (Followers: 3)
Journal of Molecular Biology Research     Open Access   (Followers: 3)
Journal of Molecular Microbiology and Biotechnology     Full-text available via subscription   (Followers: 13)
Journal of Molecular Psychiatry     Open Access   (Followers: 9)
Journal of Morphology     Hybrid Journal   (Followers: 5)
Journal of Pharmacy & Bioresources     Full-text available via subscription   (Followers: 2)
Journal of Plant Molecular Biology and Biotechnology     Open Access   (Followers: 8)
Journal of Plant Pathology & Microbiology     Open Access   (Followers: 1)
Journal of Proteome Science and Computational Biology     Open Access  
Journal of Regenerative Medicine and Tissue Engineering     Open Access   (Followers: 4)
Journal of The Academy of Clinical Microbiologists     Open Access  
Journal of the American Society of Brewing Chemists     Full-text available via subscription   (Followers: 2)
Journal of the Institute of Brewing     Free   (Followers: 3)
Journal of Tropical Microbiology and Biotechnology     Full-text available via subscription  
Jundishapur Journal of Microbiology     Open Access  
Letters In Applied Microbiology     Hybrid Journal   (Followers: 6)
Macrophage     Open Access  
MAP Kinase     Open Access  
Medical Mycology     Open Access   (Followers: 5)
Memórias do Instituto Oswaldo Cruz     Open Access  
Methods in Molecular Biology     Hybrid Journal   (Followers: 19)
Microbes and Health     Open Access   (Followers: 1)
Microbes and Infection     Full-text available via subscription   (Followers: 5)
Microbial Biotechnology     Open Access   (Followers: 8)
Microbial Cell Factories     Open Access   (Followers: 7)
Microbial Drug Resistance     Hybrid Journal   (Followers: 4)
Microbial Ecology     Hybrid Journal   (Followers: 9)
Microbial Ecology in Health and Disease     Open Access  
Microbial Informatics and Experimentation     Open Access   (Followers: 1)
Microbial Pathogenesis     Hybrid Journal   (Followers: 7)
Microbial Risk Analysis     Full-text available via subscription  
Microbiologia Medica     Open Access   (Followers: 1)
Microbiological Research     Hybrid Journal   (Followers: 6)
Microbiology     Hybrid Journal   (Followers: 13)
Microbiology (SGM)     Full-text available via subscription   (Followers: 18)
Microbiology and Immunology     Hybrid Journal   (Followers: 10)
Microbiology and Molecular Biology Reviews     Hybrid Journal   (Followers: 24)
Microbiology Australia     Hybrid Journal  
Microbiology Discovery     Open Access   (Followers: 1)
Microbiology Indonesia     Open Access  
Microbiology Research     Open Access   (Followers: 7)
MicrobiologyOpen     Open Access   (Followers: 2)
Microbiome     Hybrid Journal   (Followers: 6)
Microbiome Science and Medicine     Open Access   (Followers: 2)
Microorganisms     Open Access   (Followers: 2)
MicroRNA     Hybrid Journal   (Followers: 1)
Molecular and Cellular Therapies     Open Access  
Molecular Biology and Genetic Engineering     Open Access   (Followers: 1)
Molecular Biology Research Communications     Open Access   (Followers: 1)
Molecular Genetics and Metabolism Reports     Open Access   (Followers: 2)
Molecular Genetics, Microbiology and Virology     Hybrid Journal   (Followers: 7)
Molecular Imaging     Open Access  
Molecular Imaging and Biology     Hybrid Journal   (Followers: 2)
Molecular Medicine     Open Access   (Followers: 3)
Molecular Medicine Reports     Full-text available via subscription   (Followers: 5)
Molecular Microbiology     Hybrid Journal   (Followers: 31)
Molecular Oral Microbiology     Partially Free   (Followers: 3)
Molecular Systems Biology     Open Access   (Followers: 9)

        1 2 | Last

Journal Cover International Journal of Food Microbiology
  [SJR: 1.64]   [H-I: 142]   [12 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0168-1605
   Published by Elsevier Homepage  [3030 journals]
  • Sensory profile and volatile aroma composition of reduced alcohol Merlot
           wines fermented with Metschnikowia pulcherrima and Saccharomyces uvarum
    • Authors: C. Varela; A. Barker; T. Tran; A. Borneman; C. Curtin
      Pages: 1 - 9
      Abstract: Publication date: 3 July 2017
      Source:International Journal of Food Microbiology, Volume 252
      Author(s): C. Varela, A. Barker, T. Tran, A. Borneman, C. Curtin
      Strategies for production of wines containing lower alcohol concentrations are in strong demand, for reasons of quality, health, and taxation. Development and application of wine yeasts that are less efficient at transforming grape sugars into ethanol has the potential to allow winemakers the freedom to make lower alcohol wines from grapes harvested at optimal ripeness, without the need for post-fermentation processes aimed at removing ethanol. We have recently shown that two non-conventional wine yeast species Metschnikowia pulcherrima and Saccharomyces uvarum were both able to produce wine with reduced alcohol concentration. Both species produced laboratory-scale wines with markedly different volatile aroma compound composition relative to Saccharomyces cerevisiae. This work describes the volatile composition and sensory profiles of reduced-alcohol pilot-scale Merlot wines produced with M. pulcherrima and S. uvarum. Wines fermented with M. pulcherrima contained 1.0% v/v less ethanol than S. cerevisiae fermented wines, while those fermented with S. uvarum showed a 1.7% v/v reduction in ethanol. Compared to S. cerevisiae ferments, wines produced with M. pulcherrima showed higher concentrations of ethyl acetate, total esters, total higher alcohols and total sulfur compounds, while wines fermented with S. uvarum were characterised by the highest total concentration of higher alcohols. Sensorially, M. pulcherrima wines received relatively high scores for sensory descriptors such as red fruit and fruit flavour and overall exhibited a sensory profile similar to that of wine made with S. cerevisiae, whereas the main sensory descriptors associated with wines fermented with S. uvarum were barnyard and meat. This work demonstrates the successful application of M. pulcherrima AWRI3050 for the production of pilot-scale red wines with reduced alcohol concentration and highlights the need for rigorous evaluation of non-conventional yeasts with regard to their sensory impacts.

      PubDate: 2017-04-26T16:47:26Z
      DOI: 10.1016/j.ijfoodmicro.2017.04.002
      Issue No: Vol. 252 (2017)
  • Modelling the effect of combined antimicrobials: A base model for
    • Authors: M. Anastasiadi; R.J.W. Lambert
      Pages: 10 - 17
      Abstract: Publication date: 3 July 2017
      Source:International Journal of Food Microbiology, Volume 252
      Author(s): M. Anastasiadi, R.J.W. Lambert
      Combining antimicrobials to reduce microbial growth and to combat the potential impact of antimicrobial resistance is an important subject both in foods and in pharmaceutics. Modelling of combined treatments designed to reduce or eliminate microbial contamination in foods (microbiological predictive modelling) has become commonplace. Two main reference models are used to analyse mixtures: the Bliss Independence and the Loewe reference models (LRM). By using optical density to analyse the growth of Aeromonas hydrophila, Cronobacter sakazakii and Escherichia coli in combined NaCl/NaCl (a mock combination experiment) and combined NaCl/KCl experiments, previous models for combined antimicrobials in foods, based on the Bliss approach, were shown to be inconsistent and that models based on the LRM more applicable. The LRM was shown, however, to be valid only in the specific cases where the concentration exponents of all components in a mixture were identical. This is assured for a mock combination experiment but not for a true mixture. This, essentially, invalidates the LRM as a general reference model. A new model, based on the LRM but allowing for mixed exponents, was used to analyse the combined inhibition data, and concluded that the NaCl/KCl system gave the additive effect expected from literature studies. This study suggests the need to revise current models used to analyse combined effects.

      PubDate: 2017-04-26T16:47:26Z
      DOI: 10.1016/j.ijfoodmicro.2017.04.004
      Issue No: Vol. 252 (2017)
  • Antimicrobial activity of free and liposome-encapsulated thymol and
           carvacrol against Salmonella and Staphylococcus aureus adhered to
           stainless steel
    • Authors: Juliana Both Engel; Caroline Heckler; Eduardo Cesar Tondo; Daniel Joner Daroit; Patrícia da Silva Malheiros
      Pages: 18 - 23
      Abstract: Publication date: 3 July 2017
      Source:International Journal of Food Microbiology, Volume 252
      Author(s): Juliana Both Engel, Caroline Heckler, Eduardo Cesar Tondo, Daniel Joner Daroit, Patrícia da Silva Malheiros
      Antimicrobial activity of thymol, carvacrol and thymol/carvacrol liposomes (TCL) was evaluated against two bacterial pools, each one consisting of four strains of Staphylococcus aureus or Salmonella enterica. TCL were prepared using thin-film hydration, showing 270.20nm average diameter (polydispersity index of 0.33) and zeta potential of +39.99mV. Minimum inhibitory concentration (MIC) of thymol, carvacrol and TCL against S. aureus pool was 0.662mg/ml, while MIC for Salmonella pool was 0.331mg/ml for thymol and carvacrol, and for TCL was 0.662mg/ml. Bacterial pools (8.0logCFU/ml), allowed in contact on stainless steel AISI 304 coupons in UHT skim milk for 15min, resulted in adhered populations of 5.6–6.1logCFU/cm2. Adhered S. aureus (±6.1logCFU/cm2) were inhibited after 1-min and 10-min treatments using thymol or carvacrol at MIC and 2.0 MIC. Reductions of 1.47–1.76logCFU/cm2 and 1.87–2.04logCFU/cm2 were obtained using 0.5 MIC of thymol and carvacrol, respectively. A 10-min contact with free (MIC and 2.0 MIC) and encapsulated (MIC) antimicrobials inhibited attached Salmonella (±6.0logCFU/cm2); however, after 1-min of contact, 2.0 MIC of thymol and carvacrol were not able to inactivate adhered Salmonella MIC of TCL inactivated S. aureus and Salmonella after 10min; however, after 1-min contact, adhered S. aureus and Salmonella populations were decreased in 1.62logCFU/cm2 and 2.01logCFU/cm2, respectively. Considering antimicrobial concentrations and contact times, thymol, carvacrol, and TCL could be employed in food-contact surfaces to prevent biofilm formation at early stages of bacterial attachment. Further investigations should be performed considering long-term antibacterial effects of TCL.

      PubDate: 2017-04-26T16:47:26Z
      DOI: 10.1016/j.ijfoodmicro.2017.04.003
      Issue No: Vol. 252 (2017)
  • Whey protein isolate/cellulose nanofibre/TiO2 nanoparticle/rosemary
           essential oil nanocomposite film: Its effect on microbial and sensory
           quality of lamb meat and growth of common foodborne pathogenic bacteria
           during refrigeration
    • Authors: Mahmood Alizadeh Sani; Ali Ehsani; Mohammad Hashemi
      Pages: 8 - 14
      Abstract: Publication date: 19 June 2017
      Source:International Journal of Food Microbiology, Volume 251
      Author(s): Mahmood Alizadeh Sani, Ali Ehsani, Mohammad Hashemi
      The use of biodegradable nanocomposite films in active packaging is of great importance since they can have a controlled release of antimicrobial compounds. This study was conducted to evaluate the efficacy of whey protein isolate (WPI)/cellulose nanofibre (CNF) nanocomposite films containing 1.0% (w/w) titanium dioxide (TiO2) and 2.0% (w/v) rosemary essential oil (REO) in preserving the microbial and sensory quality of lamb meat during the storage at 4±1°C. Initially, the best concentration of each compound to be added to the film was determined by micro-dilution and disc diffusion methods. The microbial and sensory properties of lamb meat were controlled in two groups (control and treatment) over 15days of storage. Then, the samples were analysed for total viable count (TVC), Pseudomonas spp. count, Enterobacteriaceae count, Lactic acid bacteria (LAB) count, inoculated Staphylococcus aureus count, Listeria monocytogenes count, and Escherichia coli O157:H7 count. Microbial analysis and nine-point hedonic scale was applied for the sensory analysis. Results indicated that the use of nanocomposite films significantly reduced the bacterial counts of treatment group. Higher inhibition effect was observed on Gram-positive bacteria than on Gram-negative bacteria (P <0.05). The microbial and sensory evaluations also showed that the use of nanocomposite films significantly increased the shelf life of treated meat (15days) compared to the control meat (6days). Based on the results of this study, the edible nanocomposite films were effective in preserving the microbial and sensory qualities of lamb meat; therefore, this application is recommended in meat especially red meat.

      PubDate: 2017-04-05T10:06:35Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.018
      Issue No: Vol. 251 (2017)
  • Changes in thermo-tolerance and survival under simulated gastrointestinal
           conditions of Salmonella Enteritidis PT4 and Salmonella Typhimurium PT4 in
           chicken breast meat after exposure to sequential stresses
    • Authors: Adma Nadja Ferreira de Melo; Geany Targino de Souza; Donald Schaffner; Tereza C. Moreira de Oliveira; Janeeyre Ferreira Maciel; Evandro Leite de Souza; Marciane Magnani
      Pages: 15 - 23
      Abstract: Publication date: 19 June 2017
      Source:International Journal of Food Microbiology, Volume 251
      Author(s): Adma Nadja Ferreira de Melo, Geany Targino de Souza, Donald Schaffner, Tereza C. Moreira de Oliveira, Janeeyre Ferreira Maciel, Evandro Leite de Souza, Marciane Magnani
      This study assessed changes in thermo-tolerance and capability to survive to simulated gastrointestinal conditions of Salmonella Enteritidis PT4 and Salmonella Typhimurium PT4 inoculated in chicken breast meat following exposure to stresses (cold, acid and osmotic) commonly imposed during food processing. The effects of the stress imposed by exposure to oregano (Origanum vulgare L.) essential oil (OVEO) on thermo-tolerance were also assessed. After exposure to cold stress (5°C for 5h) in chicken breast meat the test strains were sequentially exposed to the different stressing substances (lactic acid, NaCl or OVEO) at sub-lethal amounts, which were defined considering previously determined minimum inhibitory concentrations, and finally to thermal treatment (55°C for 30min). Resistant cells from distinct sequential treatments were exposed to simulated gastrointestinal conditions. The exposure to cold stress did not result in increased tolerance to acid stress (lactic acid: 5 and 2.5μL/g) for both strains. Cells of S. Typhimurium PT4 and S. Enteritidis PT4 previously exposed to acid stress showed higher (p<0.05) tolerance to osmotic stress (NaCl: 75 or 37.5mg/g) compared to non-acid-exposed cells. Exposure to osmotic stress without previous exposure to acid stress caused a salt-concentration dependent decrease in counts for both strains. Exposure to OVEO (1.25 and 0.62μL/g) decreased the acid and osmotic tolerance of both S. Enteritidis PT4 and S. Typhimurium PT4. Sequential exposure to acid and osmotic stress conditions after cold exposure increased (p<0.05) the thermo-tolerance in both strains. The cells that survived the sequential stress exposure (resistant) showed higher tolerance (p<0.05) to acidic conditions during continuous exposure (182min) to simulated gastrointestinal conditions. Resistant cells of S. Enteritidis PT4 and S. Typhimurium PT4 showed higher survival rates (p<0.05) than control cells at the end of the in vitro digestion. These results show that sequential exposure to multiple sub-lethal stresses may increase the thermo-tolerance and enhance the survival under gastrointestinal conditions of S. Enteritidis PT4 and S. Typhimurium PT4.

      PubDate: 2017-04-05T10:06:35Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.022
      Issue No: Vol. 251 (2017)
  • Mycotoxin risk assessment for consumers of groundnut in domestic markets
           in Nigeria
    • Authors: Oluwawapelumi A. Oyedele; Chibundu N. Ezekiel; Michael Sulyok; Modupeade C. Adetunji; Benedikt Warth; Olusegun O. Atanda; Rudolf Krska
      Pages: 24 - 32
      Abstract: Publication date: 19 June 2017
      Source:International Journal of Food Microbiology, Volume 251
      Author(s): Oluwawapelumi A. Oyedele, Chibundu N. Ezekiel, Michael Sulyok, Modupeade C. Adetunji, Benedikt Warth, Olusegun O. Atanda, Rudolf Krska
      The fungal and multi-mycotoxin profiles of groundnuts sold in domestic markets in Nigeria as well as the associated risk to consumers were assessed in the present study. Four hundred fungal isolates representing mainly Aspergillus [58.6%: Aspergillus section Flavi (37.1%) and A. niger-clade (21.5%)], Penicillium (40.9%) and Fusarium (0.5%) were isolated from 82 (97.6%, n =84) groundnut samples collected from four agro-ecological zones (AEZs) of Nigeria. The incidence of aflatoxin-producing A. flavus isolates (71%) was significantly (p <0.05) higher in the groundnuts than that of the non-aflatoxigenic isolates (29%). Fifty-four fungal metabolites [including aflatoxins (AFB1, AFB2, AFG1, AFG2 and AFM1), beauvericin (BEAU), cyclopiazonic acid (CPA), moniliformin, nivalenol and ochratoxin A] and four bacterial metabolites were detected in the groundnuts by liquid chromatography tandem mass spectrometry. Aflatoxins (39%; max: 2076μg/kg; mean: 216μg/kg) were detected in more samples than any other mycotoxin. About 25, 23 and 14% of the samples respectively were above the 2μg/kg AFB1, 4 and 20μg/kg total aflatoxin limits of the European Union and US FDA respectively. The mean margins of exposure of AFB1 and total aflatoxins for adult consumers were 1665 and 908, respectively, while mean estimated daily intake values for infants, children and adults were <0.1% for BEAU and 4% for CPA. Consumers of mycotoxin contaminated groundnuts in Nigeria may therefore be at a risk of liver cancer in addition to other combinatory effects of mycotoxin/metabolite cocktails. There is need for increased targeted interventions in the groundnut value chain in Nigeria for public health benefits.

      PubDate: 2017-04-05T10:06:35Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.020
      Issue No: Vol. 251 (2017)
  • Recovering traditional raw-milk Tetilla cheese flavour and sensory
           attributes by using Kocuria varians and Yarrowia lipolytica adjunct
    • Authors: J.A. Centeno; J.I. Garabal; F. Docampo; J.M. Lorenzo; J. Carballo
      Pages: 33 - 40
      Abstract: Publication date: 19 June 2017
      Source:International Journal of Food Microbiology, Volume 251
      Author(s): J.A. Centeno, J.I. Garabal, F. Docampo, J.M. Lorenzo, J. Carballo
      The rationale of the present study was to evaluate the potential of microbial adjunct cultures including Kocuria varians and/or Yarrowia lipolytica strains in the recovery of the typical sensory profile of traditional (raw-milk) Tetilla cheese. Four batches of Tetilla cheese, a short ripened cows' milk cheese produced in Galicia (NW Spain), were made in duplicate from pasteurized milk inoculated with different microbial cultures. A control batch was manufactured by adding a mesophilic commercial D-starter only. The other three batches were made with the same starter after a cheese-milk pre-ripening step carried out with (i) an adjunct culture of K. varians, (ii) an adjunct culture of Y. lipolytica, or (iii) a combination of both adjunct cultures. The highest pH and water activity values, associated with softer textures were determined in the cheeses manufactured with the Y. lipolytica adjunct after 21days of ripening. The contents of the volatile compounds 3-methylbutanol, dimethyl disulfide and dimethyl trisulfide were higher in the cheeses made with only the K. varians adjunct than in the cheeses made with the only yeast adjunct and in the control cheeses. The contents of hexanoic and octanoic acids were highest in the cheeses made with the Y. lipolytica adjunct, and levels of ethyl hexanoate, ethyl octanoate and ethyl decanoate were higher in the cheeses made with only the yeast adjunct than in the other batches of cheese. The cheeses manufactured with both adjunct cultures were awarded the highest scores for flavour and overall sensory parameters (considering the standards of the traditional product) and were considered very similar to ‘good quality’ artisanal raw-milk cheeses. We conclude that use of selected Micrococcaceae and Y. lipolytica strains as adjunct cultures would differentiate the sensory properties and contribute to the quality and typicality of the short-ripened rennet-curd Galician Tetilla and Arzúa-Ulloa cheeses.

      PubDate: 2017-04-05T10:06:35Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.014
      Issue No: Vol. 251 (2017)
  • Evidence of Campylobacter jejuni reduction in broilers with early
           synbiotic administration
    • Authors: Loredana Baffoni; Francesca Gaggìa; Giuliano Garofolo; Gabriella Di Serafino; Enrico Buglione; Elisabetta Di Giannatale; Diana Di Gioia
      Pages: 41 - 47
      Abstract: Publication date: 19 June 2017
      Source:International Journal of Food Microbiology, Volume 251
      Author(s): Loredana Baffoni, Francesca Gaggìa, Giuliano Garofolo, Gabriella Di Serafino, Enrico Buglione, Elisabetta Di Giannatale, Diana Di Gioia
      C. jejuni is considered a food safety concern to both public health authorities and consumers since it is the leading bacterial cause of food-borne gastroenteritis in humans. A high incidence of C. jejuni in broiler flocks is often correlated to pathogen recovery in retail poultry meat, which is the main source of human infection. In this work broiler chickens were fed with a synbiotic product mixed with conventional feed using two different administration strategies. The synbiotic was formulated with the microencapsulated probiotic Bifidobacterium longum PCB133 and a xylo-oligosaccharide (XOS). 1-day old chicks were infected with C. jejuni strain M1 (105 cells) and the synbiotic mixture was then administered starting from the first and the 14th day of chicken life (for animal groups GrpC and GrpB respectively). The goal of this study was to monitor C. jejuni load at caecum level at different sampling time by real-time PCR, identifying the best administration strategy. The microbiological analysis of the caecal content also considered the quantification of Campylobacter spp., Bifidobacterium spp. and B. longum. The supplemented synbiotic was more successful in reducing C. jejuni and Campylobacter spp. when administered lifelong, compared to the shorter supplementation (GrpB). Bifidobacterium spp. quantification did not show significant differences among treatments and B. longum PCB133 was detected in both supplemented groups evidencing the successful colonization of the strain. Moreover, the samples of the control group (GrpA) and GrpC were analysed with PCR-denaturing gradient gel electrophoresis (PCR-DGGE) to compare the caecal microbial community profiles at the beginning and at the end of the trial. Pattern analysis evidenced the strong influence of the early synbiotic supplementation, although a physiological change in the microbial community, occurring during growth, could be observed. Experimental results demonstrate that the synbiotic approach at farm level can be an effective strategy, combined with biosecurity measures, to improve the safety of poultry meat.

      PubDate: 2017-04-12T02:06:09Z
      DOI: 10.1016/j.ijfoodmicro.2017.04.001
      Issue No: Vol. 251 (2017)
  • Antimicrobial activity of Olea europaea Linné extracts and their
           applicability as natural food preservative agents
    • Authors: J. Thielmann; S. Kohnen; C. Hauser
      Pages: 48 - 66
      Abstract: Publication date: 19 June 2017
      Source:International Journal of Food Microbiology, Volume 251
      Author(s): J. Thielmann, S. Kohnen, C. Hauser
      The antimicrobial activity of phenolic compounds from Olea (O.) europaea Linné (L.) is part of the scientific discussion regarding the use of natural plant extracts as alternative food preservative agents. Although, the basic knowledge on the antimicrobial potential of certain molecules such as oleuropein, hydroxytyrosol or elenolic acid derivatives is given, there is still little information regarding their applicability for food preservation. This might be primarily due to the lack of information regarding the full antimicrobial spectrum of the compounds, their synergisms in natural or artificial combinations and their interaction with food ingredients. The present review accumulates available literature from the past 40 years, investigating the antimicrobial activity of O. europaea L. derived extracts and compounds in vitro and in food matrices, in order to evaluate their food applicability. In summary, defined extracts from olive fruit or leaves, containing the strongest antimicrobial compounds hydroxytyrosol, oleacein or oleacanthal in considerable concentrations, appear to be suitable for food preservation. Nonetheless there is still need for consequent research on the compounds activity in food matrices, their effect on the natural microbiota of certain foods and their influence on the sensorial properties of the targeted products.

      PubDate: 2017-04-12T02:06:09Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.019
      Issue No: Vol. 251 (2017)
  • Characterization of bacterial communities of donkey milk by
           high-throughput sequencing
    • Authors: Maria de los Dolores Soto del Rio; Alessandra Dalmasso; Tiziana Civera; Maria Teresa Bottero
      Pages: 67 - 72
      Abstract: Publication date: 19 June 2017
      Source:International Journal of Food Microbiology, Volume 251
      Author(s): Maria de los Dolores Soto del Rio, Alessandra Dalmasso, Tiziana Civera, Maria Teresa Bottero
      The interest in donkey milk (DM) is growing because of its functional properties and nutritional value, especially for children with allergies and food intolerances. However, most of the available reports of DM microbiota are based on culture-dependent methods to investigate food safety issues and the presence of lactic acid bacteria (LAB). The aim of this study was to determine the composition of DM bacterial communities using a high-throughput sequencing (HTS) approach. Bulk milk samples from Italian donkey dairy farms from two consecutive years were analysed using the MiSeq Illumina platform. All sample reads were classified into five phyla: Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, and Verrucomicrobia. The most prevalent genera—Pseudomonas, Ralstonia, Acinetobacter, Cupriavidus, Citrobacter and Sphingobacterium—were Gram-negative bacteria. The core microbiota was composed of genera that comprise commonly associated milk bacteria, LAB and species normally found in soil, water and plants. Reads assigned to LAB genera—Streptococcus, Lactococcus, Enterococcus, Leuconostoc, Lactobacillus, and Carnobacterium—corresponded on average to 2.55% of the total reads per sample. Among these, the distribution of reads assigned to coccus- and bacillus-shaped LAB was variable between and within the farms, confirming their presence and suggesting a complex population of these bacteria in DM. The present study represents a general snapshot of the DM microbial population, underlining its variability and motivating further studies for the exploitation of the technological potential of bacteria naturally present in DM.

      PubDate: 2017-04-19T02:21:21Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.023
      Issue No: Vol. 251 (2017)
  • Validation of the baking process as a kill-step for controlling Salmonella
           in muffins
    • Authors: Lakshmikantha H. Channaiah; Minto Michael; Jennifer C. Acuff; Randall K. Phebus; Harshavardhan Thippareddi; Maureen Olewnik; George Milliken
      Pages: 1 - 6
      Abstract: Publication date: 5 June 2017
      Source:International Journal of Food Microbiology, Volume 250
      Author(s): Lakshmikantha H. Channaiah, Minto Michael, Jennifer C. Acuff, Randall K. Phebus, Harshavardhan Thippareddi, Maureen Olewnik, George Milliken
      This research investigates the potential risk of Salmonella in muffins when contamination is introduced via flour, the main ingredient. Flour was inoculated with a 3-strain cocktail of Salmonella serovars (Newport, Typhimurium, and Senftenberg) and re-dried to achieve a target concentration of ~8logCFU/g. The inoculated flour was then used to prepare muffin batter following a standard commercial recipe. The survival of Salmonella during and after baking at 190.6°C for 21min was analyzed by plating samples on selective and injury-recovery media at regular intervals. The thermal inactivation parameters (D and z values) of the 3-strain Salmonella cocktail were determined. A ≥5logCFU/g reduction in Salmonella population was demonstrated by 17min of baking, and a 6.1logCFU/g reduction in Salmonella population by 21min of baking. The D-values of Salmonella serovar cocktail in muffin batter were 62.2±3.0, 40.1±0.9 and 16.5±1.7min at 55, 58 and 61°C, respectively; and the z-value was 10.4±0.6°C. The water activity (aw) of the muffin crumb (0.928) after baking and 30min of cooling was similar to that of pre-baked muffin batter, whereas the aw of the muffin crust decreased to (0.700). This study validates a typical commercial muffin baking process utilizing an oven temperature of 190.6°C for at least 17min as an effective kill-step in reducing a Salmonella serovar population by ≥5logCFU/g.

      PubDate: 2017-03-28T17:12:16Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.007
      Issue No: Vol. 250 (2017)
  • Stevia rebaudiana Bertoni effect on the hemolytic potential of Listeria
    • Authors: S. Sansano; A. Rivas; M.C. Pina-Pérez; A. Martinez; D. Rodrigo
      Pages: 7 - 11
      Abstract: Publication date: 5 June 2017
      Source:International Journal of Food Microbiology, Volume 250
      Author(s): S. Sansano, A. Rivas, M.C. Pina-Pérez, A. Martinez, D. Rodrigo
      The effect of Stevia rebaudiana Bertoni on the hemolytic potential of Listeria monocytogenes was studied by means of the assessment of the Listeriolysin O (LLO) production. The three factors under study, stevia concentration in the range [0–2.5] % (w/v), incubation temperature (10 and 37°C), and exposure time (0–65h) significantly affected (p ≤0.05) the hemolytic activity of L. monocytogenes. Results showed that at the lower incubation temperature the hemolytic potential of the bacterium was significantly reduced, from 100% at 37°C to 8% at 10°C (after 65h of incubation) in unsupplemented substrate (0% stevia). Irrespective of the temperature, 10 or 37°C, supplementation of the medium with stevia at 2.5 % (w/v) reduced the bacterium's hemolytic activity by a maximum of 100%. Furthermore, the time of exposure to 2.5 % (w/v) stevia concentration was also a significant factor reducing the hemolytic capability of L. monocytogenes. The possibility of reducing the pathogenic potential of L. monocytogenes (hemolysis) by exposure to stevia should be confirmed in real food matrices, opening a research niche with a valuable future impact on food safety.

      PubDate: 2017-03-28T17:12:16Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.006
      Issue No: Vol. 250 (2017)
  • Visceral larvae as a predictive index of the overall level of fish batch
           infection in European anchovies (Engraulis encrasicolus): A rapid
           procedure for Food Business Operators to assess marketability
    • Authors: L. Guardone; D. Nucera; V. Pergola; F. Costanzo; E. Costa; L. Tinacci; A. Guidi; A. Armani
      Pages: 12 - 18
      Abstract: Publication date: 5 June 2017
      Source:International Journal of Food Microbiology, Volume 250
      Author(s): L. Guardone, D. Nucera, V. Pergola, F. Costanzo, E. Costa, L. Tinacci, A. Guidi, A. Armani
      The European anchovy (Engraulis encrasicolus), one of the most important pelagic fish resources in the Mediterranean Sea, is frequently infected by anisakid larvae. Food Business Operators (FBOs) should use appropriate sampling plans and analytical methods to avoid commercialization of massively infected batches and reduce the risk of transmission of viable zoonotic larvae. In this study, performed at FishLab (Department of Veterinary Sciences of the University of Pisa) during 2016, an official sampling plan was associated with a digestion protocol for the inspection of anchovies. Considering that anisakid larvae are usually located in the fish visceral cavity and in the adjacent muscles (VM), this part was analyzed. In particular, we assessed the reliability of the digestion of a subsample of 150g (±30g) of VM, randomly collected from 29 specimens, in estimating the marketability of the anchovies' batch. Fifty-seven samples of 29 anchovies were collected. Each anchovy was sectioned to separate VM. All the subsamples were digested, and visible larvae counted. A high correlation between the number of larvae in VM regions and in the total batch was observed, indicating a very significant contribution of the VM region on total number of parasites. The Mean Abundance (MA) was used to assess the batch marketability according to a threshold calculated on the basis of the maximum number of nematodes tolerated per sample. Considering that the MA can be calculated only when the number of examined specimens is known, the number of visible Larvae per gram of tissue (LpG) was calculated on 150g (±30g) of VM subsamples. A LpG marketability threshold was calculated dividing the maximum number of tolerated nematodes by the average weight of a sample of 29 anchovies calculated considering data available in literature. To evaluate the diagnostic performance of the LpG threshold, the marketability of 57 batches assessed on the basis of the MA threshold was assumed as the gold standard. The proposed LpG showed very high Specificity and Sensitivity. These findings suggest that the analysis of VM is representative of the overall infestation of the batch, both when considering the absolute number of parasites and the LpG, and may represent a valid alternative to the whole anchovy digestion. In particular, the use of an automated digestive method, coupled with the aforesaid sampling plan, could allow the procedure to be used by FBOs in operational conditions.

      PubDate: 2017-03-28T17:12:16Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.011
      Issue No: Vol. 250 (2017)
  • Identification and characterization of lactic acid bacteria and yeasts of
           PDO Tuscan bread sourdough by culture dependent and independent methods
    • Authors: Michela Palla; Caterina Cristani; Manuela Giovannetti; Monica Agnolucci
      Pages: 19 - 26
      Abstract: Publication date: 5 June 2017
      Source:International Journal of Food Microbiology, Volume 250
      Author(s): Michela Palla, Caterina Cristani, Manuela Giovannetti, Monica Agnolucci
      Sourdough fermentation has been increasingly used worldwide, in accordance with the demand of consumers for tasty, natural and healthy food. The high diversity of lactic acid bacteria (LAB) and yeast species, detected in sourdoughs all over the world, may affect nutritional, organoleptic and technological traits of leavened baked goods. A wide regional variety of traditional sourdough breads, over 200 types, has been recorded in Italy, including special types selected as worthy of either Protected Geographical Indication (PGI) or Protected Designation of Origin (PDO), whose sourdough microbiota has been functionally and molecularly characterized. As, due to the very recent designation, the microbiota of Tuscan bread sourdough has not been investigated so far, the aim of the present work was to isolate and characterize the species composition of LAB and yeasts of PDO Tuscan bread sourdough by culture-independent and dependent methods. A total of 130 yeasts from WLN medium and 193 LAB from both mMRS and SDB media were isolated and maintained to constitute the germplasm bank of PDO Tuscan bread. Ninety six LAB from mMRS medium and 68 yeasts from WLN medium were randomly selected and molecularly identified by ARDRA (Amplified Ribosomal DNA Restriction Analysis) and PCR-RFLP analysis of the ITS region, respectively, and sequencing. The yeast identity was confirmed by 26S D1/D2 sequencing. All bacterial isolates showed 99% identity with Lactobacillus sanfranciscensis, 65 yeast isolates were identified as Candida milleri, and 3 as Saccharomyces cerevisiae. Molecular characterization of PDO Tuscan bread sourdough by PCR-DGGE confirmed such data. The distinctive tripartite species association, detected as the microbiota characterizing the sourdough used to produce PDO Tuscan bread, encompassed a large number of L. sanfranciscensis and C. milleri strains, along with a few of S. cerevisiae. The relative composition and specific physiological characteristics of such microbiota could potentially affect the nutritional features of PDO Tuscan bread, as suggested by the qualitative functional characterization of the isolates. Investigations on the differential functional traits of such LAB and yeast isolates could lead to the selection of the most effective single strains and of the best performing strain combinations to be used as starters for the production of baked goods.

      PubDate: 2017-03-28T17:12:16Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.015
      Issue No: Vol. 250 (2017)
  • African fermented dairy products – Overview of predominant
           technologically important microorganisms focusing on African Streptococcus
           infantarius variants and potential future applications for enhanced food
           safety and security
    • Authors: Christoph Jans; Leo Meile; Dasel Wambua Mulwa Kaindi; Wambui Kogi-Makau; Peter Lamuka; Pierre Renault; Bernd Kreikemeyer; Christophe Lacroix; Jan Hattendorf; Jakob Zinsstag; Esther Schelling; Gilbert Fokou; Bassirou Bonfoh
      Pages: 27 - 36
      Abstract: Publication date: 5 June 2017
      Source:International Journal of Food Microbiology, Volume 250
      Author(s): Christoph Jans, Leo Meile, Dasel Wambua Mulwa Kaindi, Wambui Kogi-Makau, Peter Lamuka, Pierre Renault, Bernd Kreikemeyer, Christophe Lacroix, Jan Hattendorf, Jakob Zinsstag, Esther Schelling, Gilbert Fokou, Bassirou Bonfoh
      Milk is a major source of nutrients, but can also be a vehicle for zoonotic foodborne diseases, especially when raw milk is consumed. In Africa, poor processing and storage conditions contribute to contamination, outgrowth and transmission of pathogens, which lead to spoilage, reduced food safety and security. Fermentation helps mitigate the impact of poor handling and storage conditions by enhancing shelf life and food safety. Traditionally-fermented sour milk products are culturally accepted and widely distributed in Africa, and rely on product-specific microbiota responsible for aroma, flavor and texture. Knowledge of microbiota and predominant, technologically important microorganisms is critical in developing products with enhanced quality and safety, as well as sustainable interventions for these products, including Africa-specific starter culture development. This narrative review summarizes current knowledge of technologically-important microorganisms of African fermented dairy products (FDP) and raw milk, taking into consideration novel findings and taxonomy when re-analyzing data of 29 publications covering 25 products from 17 African countries. Technologically-important lactic acid bacteria such as Lactococcus lactis and Streptococcus infantarius subsp. infantarius (Sii), Lactobacillus spp. and yeasts predominated in raw milk and FDP across Africa. Re-analysis of data also suggests a much wider distribution of Sii and thus a potentially longer history of use than previously expected. Therefore, evaluating the role and safety of African Sii lineages is important when developing interventions and starter cultures for FDP in Africa to enhance food safety and food security. In-depth functional genomics, epidemiologic investigations and latest identification approaches coupled with stakeholder involvement will be required to evaluate the possibility of African Sii lineages as novel food-grade Streptococcus lineage.

      PubDate: 2017-04-05T10:06:35Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.012
      Issue No: Vol. 250 (2017)
  • Biocontrol of the internalization of Salmonella enterica and
           Enterohaemorrhagic Escherichia coli in mung bean sprouts with an
           endophytic Bacillus subtilis
    • Authors: Zhenyu Shen; Azlin Mustapha; Mengshi Lin; Guolu Zheng
      Pages: 37 - 44
      Abstract: Publication date: 5 June 2017
      Source:International Journal of Food Microbiology, Volume 250
      Author(s): Zhenyu Shen, Azlin Mustapha, Mengshi Lin, Guolu Zheng
      Internalization of Salmonella enterica and enterohaemorrhagic Escherichia coli (EHEC) in seed sprouts poses a health risk to consumers, and the conventional sanitization methods are not always effective to reduce this risk. This study initiated a biocontrol approach to limit the internalization using endophytic Bacillus subtilis strains, which were isolated from the inner tissue of mung bean seeds or lettuce stems. By using the deferred agar method, 12 strains of B. subtilis out of 94 putative Bacillus isolates displayed inhibitory activity against at least one of the pathogenic indicators, S. enterica Typhimurium ATCC 14028 and E. coli O157:H7 505B. Two B. subtilis isolates (LCA1 and M24) showed a broad inhibitory spectrum against multiple strains of S. enterica and EHEC, Staphylococcus aureus sp., Klebsiella pneumoniae ATCC 700603, and Listeria monocytogenes Scott A, while the laboratory B. subtilis strain 168 was only moderately inhibitory against L. monocytogenes. To facilitate the tracking of the three B. subtilis strains (LCA1, M24, and 168) in the mung bean sprouts, the three strains were genetically engineered to carry the chloramphenicol acetyltransferase (cat), generating the strains LCA1-cat, M24-cat, and 168-cat, respectively. Data of the study using the cat-tagged strains demonstrated that both the two vegetable-associated and the laboratory B. subtilis strains could internalize in mung bean sprouts during the sprouting, but the latter displayed about 1.2 lg CFU/g of seeds lower in internalization. Overall, the presence of the three B. subtilis strains could significantly reduce the internalization of S. enterica or EHEC cocktail in mung bean sprouts during the sprouting. Among them, LCA1 showed the greatest inhibition against the EHEC cocktails with a reduction of about 2.0lg CFU/g of seeds by the end of sprouting (day 5), while 168 had the smallest reduction at about 0.6lg CFU/g of seeds. In addition, the three strains demonstrated a similar inhibition against the S. enterica cocktails by a reduction of about 1.1–1.4lg CFU/g of seeds by day 5. Results of this study suggest that the source (native vs. alien) of B. subtilis isolates may not affect the efficacy of the inhibition, but it might be affected by the production of antimicrobial substance and/or nutrition/space competition. The results also indicate that strain LCA1 may be useful as a biocontrol agent to reduce Salmonella and EHEC contamination in seed sprouts.

      PubDate: 2017-04-05T10:06:35Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.016
      Issue No: Vol. 250 (2017)
  • Kazachstania gamospora and Wickerhamomyces subpelliculosus: Two
           alternative baker’s yeasts in the modern bakery
    • Authors: Nerve Zhou; Anna Judith Schifferdecker; Amparo Gamero; Concetta Compagno; Teun Boekhout; Jure Piškur; Wolfgang Knecht
      Pages: 45 - 58
      Abstract: Publication date: 5 June 2017
      Source:International Journal of Food Microbiology, Volume 250
      Author(s): Nerve Zhou, Anna Judith Schifferdecker, Amparo Gamero, Concetta Compagno, Teun Boekhout, Jure Piškur, Wolfgang Knecht
      Saccharomyces cerevisiae, the conventional baker’s yeast, remains the most domesticated yeast monopolizing the baking industry. Its rapid consumption of sugars and production of CO2 are the most important attributes required to leaven the dough. New research attempts highlight that these attributes are not unique to S. cerevisiae, but also found in several non-conventional yeast species. A small number of these yeast species with similar properties have been described, but remain poorly studied. They present a vast untapped potential for the use as leavening agents and flavor producers due to their genetic and phylogenetic diversity. We assessed the potential of several non-conventional yeasts as leavening agents and flavor producers in dough-like conditions in the presence of high sugar concentrations and stressful environments mimicking conditions found in flour dough. We tested the capabilities of bread leavening and aroma formation in a microbread platform as well as in a bakery setup. Bread leavened with Kazachstania gamospora and Wickerhamomyces subpelliculosus had better overall results compared to control baker’s yeast. In addition, both displayed higher stress tolerance and broader aroma profiles than the control baker’s yeast. These attributes are important in bread and other farinaceous products, making K. gamospora and W. subpelliculosus highly applicable as alternative baker’s yeasts.

      PubDate: 2017-04-05T10:06:35Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.013
      Issue No: Vol. 250 (2017)
  • Bacillus licheniformis affects the microbial community and metabolic
           profile in the spontaneous fermentation of Daqu starter for Chinese liquor
    • Authors: Peng Wang; Qun Wu; Xuejian Jiang; Zhiqiang Wang; Jingli Tang; Yan Xu
      Pages: 59 - 67
      Abstract: Publication date: 5 June 2017
      Source:International Journal of Food Microbiology, Volume 250
      Author(s): Peng Wang, Qun Wu, Xuejian Jiang, Zhiqiang Wang, Jingli Tang, Yan Xu
      Chinese liquor is produced from spontaneous fermentation starter (Daqu) that provides the microbes, enzymes and flavors for liquor fermentation. To improve the flavor character of Daqu, we inoculated Bacillus licheniformis and studied the effect of this strain on the community structure and metabolic profile in Daqu fermentation. The microbial relative abundance changed after the inoculation, including the increase in Bacillus, Clavispora and Aspergillus, and the decrease in Pichia, Saccharomycopsis and some other genera. This variation was also confirmed by pure culture and coculture experiments. Seventy-three metabolites were identified during Daqu fermentation process. After inoculation, the average content of aromatic compounds were significantly enriched from 0.37mg/kg to 0.90mg/kg, and the average content of pyrazines significantly increased from 0.35mg/kg to 5.71mg/kg. The increase in pyrazines was positively associated with the metabolism of the inoculated Bacillus and the native genus Clavispora, because they produced much more pyrazines in their cocultures. Whereas the increase in aromatic compounds might be related to the change of in situ metabolic activity of several native genera, in particular, Aspergillus produced more aromatic compounds in cocultures with B. licheniformis. It indicated that the inoculation of B. licheniformis altered the flavor character of Daqu by both its own metabolic activity and the variation of in situ metabolic activity. Moreover, B. licheniformis inoculation influenced the enzyme activity of Daqu, including the significant increase in amylase activity (from 1.3gstarch/g/h to 1.7gstarch/g/h), and the significant decrease in glucoamylase activity (from 627.6mgglucose/g/h to 445.6mgglucose/g/h) and esterase activity (from 28.1mgethylcaproate/g/100h to 17.2mgethylcaproate/g/100h). These effects of inoculation were important factors for regulating the metabolism of microbial communities, hence for improving the flavor profile Daqu.

      PubDate: 2017-04-05T10:06:35Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.010
      Issue No: Vol. 250 (2017)
  • Contamination by Salmonella spp., Campylobacter spp. and Listeria spp. of
           most popular chicken- and pork-sausages sold in Reunion Island
    • Authors: A. Trimoulinard; M. Beral; I. Henry; L. Atiana; V. Porphyre; C. Tessier; A. Leclercq; E. Cardinale
      Pages: 68 - 74
      Abstract: Publication date: 5 June 2017
      Source:International Journal of Food Microbiology, Volume 250
      Author(s): A. Trimoulinard, M. Beral, I. Henry, L. Atiana, V. Porphyre, C. Tessier, A. Leclercq, E. Cardinale
      One of the most popular meat products of the local “cuisine” is sausage composed with 100% chicken or 100% pork. In this study, we aimed to determine the presence of Salmonella spp., Campylobacter spp. and Listeria spp. in chicken- and pork-sausages, quantify Salmonella spp. population and identify the factors that could be associated with contamination in the outlets. Two hundred and three batches of pork and chicken sausages were randomly collected from 67 local outlets (supermarkets, groceries and butcher shops). Salmonella spp. was detected in 11.8% (95% confidence interval (CI): [10.0; 13.5]) of samples, Campylobacter spp. in 1.5% [0.7; 4.2] and Listeria monocytogenes in 5.9% [4.4; 7.3]. Most probable number of Salmonella spp. varied between 6cfu per gram to 320cfu per gram. Salmonella serotypes isolated from pork and chicken sausages were S. Typhimurium (45.8%), S. London (20.8%), S. Derby (16.7%), S. Newport (8.33%), S. Blockley (4.2%) and S. Weltevreden (4.17%). Using a logistic (mixed-effect) regression model, we found that Salmonella spp. contamination was positively associated with sausages sold in papers or plastic bags and no control of rodents. Chicken sausages were associated with a decreasing risk of Salmonella contamination. Listeria monocytogenes contamination was positively associated with the presence of fresh rodent droppings in the outlet and negatively when the staff was cleaning regularly their hands with soap and water or water only. All the sampled outlets of Reunion Island were not equivalent in terms of food safety measures. Increasing awareness of these traders remains a cornerstone to limit the presence of Salmonella spp. and Listeria spp. in sausages, particularly in a tropical context (high temperature and humidity).

      PubDate: 2017-04-05T10:06:35Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.017
      Issue No: Vol. 250 (2017)
  • Distribution of Escherichia coli O157:H7 in ground beef: Assessing the
           clustering intensity for an industrial-scale grinder and a low and
           localized initial contamination
    • Authors: Estelle Loukiadis; Clémence Bièche-Terrier; Catherine Malayrat; Franck Ferré; Philippe Cartier; Jean-Christophe Augustin
      Pages: 75 - 81
      Abstract: Publication date: 5 June 2017
      Source:International Journal of Food Microbiology, Volume 250
      Author(s): Estelle Loukiadis, Clémence Bièche-Terrier, Catherine Malayrat, Franck Ferré, Philippe Cartier, Jean-Christophe Augustin
      Undercooked ground beef is regularly implicated in food-borne outbreaks involving pathogenic Shiga toxin-producing Escherichia coli. The dispersion of bacteria during mixing processes is of major concern for quantitative microbiological risk assessment since clustering will influence the number of bacteria the consumers might get exposed to as well as the performance of sampling plans used to detect contaminated ground beef batches. In this study, batches of 25kg of ground beef were manufactured according to a process mimicking an industrial-scale grinding with three successive steps: primary grinding, mixing and final grinding. The ground beef batches were made with 100% of chilled trims or with 2/3 of chilled trims and 1/3 of frozen trims. Prior grinding, one beef trim was contaminated with approximately 106–107 CFU of E. coli O157:H7 on a surface of 0.5cm2 to reach a concentration of 10–100cells/g in ground beef. The E. coli O157:H7 distribution in ground beef was characterized by enumerating 60 samples (20 samples of 5g, 20 samples of 25g and 20 samples of 100g) and fitting a Poisson-gamma model to describe the variability of bacterial counts. The shape parameter of the gamma distribution, also known as the dispersion parameter reflecting the amount of clustering, was estimated between 1.0 and 1.6. This k-value of approximately 1 expresses a moderate level of clustering of bacterial cells in the ground beef. The impact of this clustering on the performance of sampling strategies was relatively limited in comparison to the classical hypothesis of a random repartition of pathogenic cells in mixed materials (purely Poisson distribution instead of Poisson-gamma distribution).

      PubDate: 2017-04-19T02:21:21Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.009
      Issue No: Vol. 250 (2017)
  • Effect of cinnamon essential oil on bacterial diversity and shelf-life in
    • Authors: Yuemei Zhang; Dongping Li; Jian Lv; Qingzheng Li; Chunli Kong; Yongkang Luo
      Pages: 1 - 8
      Abstract: Publication date: 16 May 2017
      Source:International Journal of Food Microbiology, Volume 249
      Author(s): Yuemei Zhang, Dongping Li, Jian Lv, Qingzheng Li, Chunli Kong, Yongkang Luo
      The present study investigated the effect of cinnamon essential oil on the quality of vacuum-packaged common carp (Cyprinus carpio) fillets stored at 4±1°C in terms of sensory scores, physicochemical characteristics (total volatile basic nitrogen (TVB-N), biogenic amines, and color), and presence of spoilage microbiota. A total of 290,753 bacterial sequences and 162 different genera belonging to 14 phyla were observed by a high-throughput sequencing technique targeting the V3–V4 region of 16S rDNA, which showed a more comprehensive estimate of microbial diversity in carp samples compared with microbial enumeration. Before storage, Macrococcus and Aeromonas were the prevalent populations in the control samples, but cinnamon essential oil decreased the relative abundance of Macrococcus in the treated samples. Variability in the predominant microbiota in different samples during chilled storage was observed. Aeromonas followed by Lactococcus were the major contaminants in the spoiled control samples. Microbial enumeration also observed relatively higher counts of Aeromonas than other spoilage microorganisms. Compared with the control samples, cinnamon essential oil inhibited the growth of Aeromonas and Lactococcus were the predominant components in the treated samples on day 10; plate counts also revealed a relatively high level of lactic acid bacteria during refrigerated storage. However, there were no significant differences (P >0.05) in the composition of dominant microbiota between these two treatments at the end of the shelf-life. Furthermore, cinnamon essential oil treatment was more effective in inhibiting the increase of TVB-N and the accumulation of biogenic amines (especially for putrescine and cadaverine levels). Based primarily on sensory analysis, the use of cinnamon essential oil extended the shelf-life of vacuum-packaged common carp fillets by about 2days.

      PubDate: 2017-03-09T14:44:54Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.008
      Issue No: Vol. 249 (2017)
  • Physiological characterization of Saccharomyces uvarum and Saccharomyces
           eubayanus from Patagonia and their potential for cidermaking
    • Authors: Melisa González Flores; María Eugenia Rodríguez; Juan Martín Oteiza; Raúl Jorge Barbagelata; Christian Ariel Lopes
      Pages: 9 - 17
      Abstract: Publication date: 16 May 2017
      Source:International Journal of Food Microbiology, Volume 249
      Author(s): Melisa González Flores, María Eugenia Rodríguez, Juan Martín Oteiza, Raúl Jorge Barbagelata, Christian Ariel Lopes
      A diversity of yeast strains belonging to the cryotolerant fermentative species S. uvarum and S. eubayanus have been recovered from natural habitats and traditional fermentations in North Patagonia. The aim of this work was to evaluate the most relevant physiological features in a set of Patagonian strains belonging to S. uvarum and S. eubayanus, in order to analyze their potentiality to be used as starter cultures for cidermaking elaborated at low temperature. We evidenced that S. uvarum strains isolated from natural habitats (Araucaria araucana bark) showed similar physiological features to S. eubayanus strains obtained from the same habitat, and different from S. uvarum strains from fermentative environments (apple chichas). We also confirm the capacity of S. uvarum to produce high glycerol levels, low acetic acid and elevated production of the higher alcohol 2-phenylethanol and 2-phenylethyl acetate and demonstrated similar properties in S. eubayanus. Finally, we evidenced for the first time the antagonistic activity of S. eubayanus and selected three strains (two S. uvarum and one S. eubayanus) bearing the best combination of features to be used as a starter culture in cidermaking.

      PubDate: 2017-03-09T14:44:54Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.018
      Issue No: Vol. 249 (2017)
  • A 3-year multi-food study of the presence and persistence of Listeria
           monocytogenes in 54 small food businesses in Ireland
    • Authors: Dara Leong; Kerrie NicAogáin; Laura Luque-Sastre; Oisin McManamon; Karen Hunt; Avelino Alvarez-Ordóñez; Johann Scollard; Achim Schmalenberger; Séamus Fanning; Conor O'Byrne; Kieran Jordan
      Pages: 18 - 26
      Abstract: Publication date: 16 May 2017
      Source:International Journal of Food Microbiology, Volume 249
      Author(s): Dara Leong, Kerrie NicAogáin, Laura Luque-Sastre, Oisin McManamon, Karen Hunt, Avelino Alvarez-Ordóñez, Johann Scollard, Achim Schmalenberger, Séamus Fanning, Conor O'Byrne, Kieran Jordan
      The problem of assessing the occurrence of the food-borne pathogen Listeria monocytogenes in the food chain, and therefore the risk of exposure of the human population, is often challenging because of the limited scope of some studies. In this study the occurrence of L. monocytogenes in food from four major food groups, dairy products, meats, seafood and vegetables, and associated food processing environments in Ireland was studied over a three-year period. Fifty-four small food businesses participated in the study and sent both food and environmental samples every 2months between 2013 and 2015. L. monocytogenes was isolated using the ISO11290 standard method. Confirmation of L. monocytogenes and identification of serogroups were achieved using a multiplex PCR assay, and for some isolates serotype was determined using commercial antisera. Pulsed- field gel electrophoresis (PFGE) analysis was performed on all isolates allowing the relatedness of isolates from different food businesses to be compared nationwide. In total, 86 distinct pulsotypes were identified. The overall occurrence of L. monocytogenes in food samples was 4.2%, while in environmental samples it was 3.8%. In general, the occurrence of L. monocytogenes in food businesses decreased over the course of the study, presumably reflecting increased awareness and vigilance. The majority of the pulsotypes detected were unique to a particular food group (63/86), while only three pulsotypes were found in all four food groups investigated. The highest occurrence in food was found in the meat category (7.5%) while seafood had the lowest rate of occurrence (1.8%). Seventeen of the pulsotypes detected in the study were persistent, where persistence was defined as repeated isolation from a single facility with a minimum time interval of 6months. Using PFGE, 11 of the pulsotypes identified in this study were indistinguishable from those of 11 clinical isolates obtained from patients in Ireland over the last 4years, highlighting the fact that these pulsotypes are capable of causing disease. Overall, the study shows the diversity of L. monocytogenes strains in the Irish food chain and highlights the ability of many of these strains to persist in food processing environments. The finding that a significant proportion of these pulsotypes are also found in clinical settings highlights the need for continued vigilance by food producers, including frequent sampling and typing of isolates detected.

      PubDate: 2017-03-09T14:44:54Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.015
      Issue No: Vol. 249 (2017)
  • Verification of radio frequency pasteurization treatment for controlling
           Aspergillus parasiticus on corn grains
    • Authors: Ajuan Zheng; Lihui Zhang; Shaojin Wang
      Pages: 27 - 34
      Abstract: Publication date: 16 May 2017
      Source:International Journal of Food Microbiology, Volume 249
      Author(s): Ajuan Zheng, Lihui Zhang, Shaojin Wang
      Radio frequency (RF) heating has been proposed and tested to achieve a required anti-fungal efficacy on various food samples due to its advantage of deeper penetration depth and better heating uniformity. The purpose of this study was to validate applications of RF treatments for controlling Aspergillus parasiticus in corn while maintaining product quality. A pilot-scale, 27.12MHz, 6kW RF heating system together with hot air heating was used to rapidly pasteurize 3.0kg corn samples. Results showed that the pasteurizing effect of RF heating on Aspergillus parasiticus increased with increasing heating temperature and holding time, and RF heating at 70°C holding in hot air for at least 12min resulted in 5–6 log reduction of Aspergillus parasiticus in corn samples with the moisture content of 15.0% w.b. Furthermore, thermal resistance of Aspergillus parasiticus decreased with increasing moisture content (MC) of corn samples. Quality (MC, water activity – a w, protein, starch, ash, fat, fatty acid, color, electrical conductivity and germination rate) of RF treated corn met the required quality standard used in cereal industry. Therefore, RF treatments can provide an effective and rapid heating method to control Aspergillus parasiticus and maintain acceptable corn quality.

      PubDate: 2017-04-26T16:47:26Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.017
      Issue No: Vol. 249 (2017)
  • Prevalence of foodborne pathogens in food from selected African countries
           – A meta-analysis
    • Authors: Narayan Paudyal; Victor Anihouvi; Joseph Hounhouigan; Maitshwarelo Ignatius Matsheka; Bonno Sekwati-Monang; Wisdom Amoa-Awua; Amy Atter; Nina Bernice Ackah; Samuel Mbugua; Agnes Asagbra; Warda Abdelgadir; Jesca Nakavuma; Mogens Jakobsen; Weihuan Fang
      Pages: 35 - 43
      Abstract: Publication date: 16 May 2017
      Source:International Journal of Food Microbiology, Volume 249
      Author(s): Narayan Paudyal, Victor Anihouvi, Joseph Hounhouigan, Maitshwarelo Ignatius Matsheka, Bonno Sekwati-Monang, Wisdom Amoa-Awua, Amy Atter, Nina Bernice Ackah, Samuel Mbugua, Agnes Asagbra, Warda Abdelgadir, Jesca Nakavuma, Mogens Jakobsen, Weihuan Fang
      Food safety information in the African region is insufficient and fragmented due to lack of surveillance, documentation and reporting, thereby resulting in inefficient utilization of resources, duplication of activities, and lack of synergy among the countries of the region. This paper reviews the prevalence of foodborne pathogens in seven African countries (Benin, Botswana, Ghana, Kenya, Nigeria, Sudan and Uganda) from papers in regional or international journals published between January 2000 and December 2015. One hundred and sixteen publications that dealt with food microbiology were reviewed for general analysis, while 66 papers on contamination of pathogenic bacteria were used for meta-analysis of prevalence. The food items were split into two categories: raw foods and ready-to-eat (RTE) foods (including street food and beverages) for meta-analysis. Majority of the reviewed studies (67.2%, 78/116) dealt with food of animal origin: 38.8% for meat and eggs, 17.2% for dairy products and 11.2% for aquatic products. Only 8.6% examined foods of plant origin (fruits and vegetables). The remaining 24.1% was the composite RTE food and beverages. Enterobacteriaceae, Escherichia coli, Salmonella, Staphylococcus aureus and Listeria monocytogenes were the most frequently reported organisms in those studies. Although the data were highly heterogeneous, a striking feature is high prevalence of the major pathogens in RTE foods, almost as high as in raw foods. E. coli averaged at 37.6% in raw foods and 31.6% in RTE foods. The corresponding prevalence for Salmonella was 19.9% vs 21.7%; S. aureus, 27.8% vs 25.1% and L. monocytogenes, 19.5% vs 6.7%. The average prevalence of foodborne pathogens in these countries was 34.2% (29.0–39.3%). Differences in food types as well as non-uniform protocols for sampling and identification might have contributed to high heterogeneity (I2 >97%) although some high prevalence data could be factual with extensive varieties of raw and RTE foods. Need for improved hygienic practices in handling of raw or RTE foods are suggested. Implementation of surveillance programs that use uniform laboratory protocols across the region could give homogeneous results.

      PubDate: 2017-03-09T14:44:54Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.002
      Issue No: Vol. 249 (2017)
  • Cold plasma-activated hydrogen peroxide aerosol inactivates Escherichia
           coli O157:H7, Salmonella Typhimurium, and Listeria innocua and maintains
           quality of grape tomato, spinach and cantaloupe
    • Authors: Yunbin Jiang; Kimberly Sokorai; Georgios Pyrgiotakis; Philip Demokritou; Xihong Li; Sudarsan Mukhopadhyay; Tony Jin; Xuetong Fan
      Pages: 53 - 60
      Abstract: Publication date: Available online 10 March 2017
      Source:International Journal of Food Microbiology
      Author(s): Yunbin Jiang, Kimberly Sokorai, Georgios Pyrgiotakis, Philip Demokritou, Xihong Li, Sudarsan Mukhopadhyay, Tony Jin, Xuetong Fan
      The purpose of this study was to investigate the efficacy of aerosolized hydrogen peroxide in inactivating bacteria and maintaining quality of grape tomatoes, baby spinach leaves and cantaloupes. Stem scars and smooth surfaces of tomatoes, spinach leaves, and cantaloupe rinds, inoculated with Escherichia coli O157:H7, Salmonella Typhimurium and Listeria innocua, were treated for 45s followed by additional 30min dwell time with hydrogen peroxide (7.8%) aerosols activated by atmospheric cold plasma. Non-inoculated samples were used to study the effects on quality and native microflora populations. Results showed that two ranges of hydrogen peroxide droplets with mean diameters of 40nm and 3.0μm were introduced into the treatment chamber. The aerosolized hydrogen peroxide treatment reduced S. Typhimurium populations by 5.0logCFU/piece, and E. coli O157:H7 and L. innocua populations from initial levels of 2.9 and 6.3logCFU/piece, respectively, to non-detectable levels (detection limit 0.6logCFU/piece) on the smooth surface of tomatoes. However, on the stem scar area of tomatoes, the reductions of E. coli O157:H7, S. Typhimurium, and L. innocua were only 1.0, 1.3, and 1.3 log, respectively. On the cantaloupe rind, the treatment reduced populations of E. coli O157:H7, S. Typhimurium and L. innocua by 4.9, 1.3, and 3.0logCFU/piece, respectively. Under the same conditions, reductions achieved on spinach leaves were 1.5, 4.2 and 4.0 log for E. coli O157:H7, S. Typhimurium and L. innocua, respectively. The treatments also significantly reduced native aerobic plate count, and yeasts and mold count of tomato fruits and spinach leaves. Furthermore, firmness and color of the samples were not significantly affected by the aerosolized hydrogen peroxide. Overall, our results showed that the efficacy of aerosolized hydrogen peroxide depended on type of inoculated bacteria, location of bacteria and type of produce items, and aerosolized hydrogen peroxide could potentially be used to sanitize fresh fruits and vegetables.

      PubDate: 2017-03-16T18:29:21Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.004
      Issue No: Vol. 249 (2017)
  • Occurrence of hepatitis A and E and norovirus GI and GII in ready-to-eat
           vegetables in Italy
    • Authors: V. Terio; M. Bottaro; E. Pavoni; M.N. Losio; A. Serraino; F. Giacometti; V. Martella; A. Mottola; A. Di Pinto; G. Tantillo
      Pages: 61 - 65
      Abstract: Publication date: Available online 14 March 2017
      Source:International Journal of Food Microbiology
      Author(s): V. Terio, M. Bottaro, E. Pavoni, M.N. Losio, A. Serraino, F. Giacometti, V. Martella, A. Mottola, A. Di Pinto, G. Tantillo
      Fresh vegetables and their ready-to-eat (RTE) salads have become increasingly recognized as potential vehicles for foodborne diseases. The EU Reg. 1441/2007 establishes microbiological criteria for bacterial pathogens for products placed on the market during their shelf-life (i.e. Salmonella spp., Listeria monocytogenes) for pre-cut fruits and vegetables (RTE) whilst it does not address the problem of contamination by enteric viruses. In this study we investigated the contamination by hepatitis A virus (HAV), hepatitis E virus (HEV) and norovirus (NoV) in 911 ready-to-eat vegetable samples taken from products at retail in Apulia and in Lombardia. The vegetable samples were tested using validated real-time PCR (RT-qPCR) assays, ISO standardized virological methods and ISO culturing methods for bacteriological analysis. The total prevalence of HAV and HEV was 1.9% (18/911) and 0.6% (6/911), respectively. None of the samples analysed in this study was positive for NoV, Salmonella spp. or Listeria monocytogenes. The detection of HAV and HEV in RTE salads highlights a risk to consumers and the need to improve production hygiene. Appropriate implementation of hygiene procedures is required at all the steps of the RTE vegetable production chain and this should include monitoring of emerging viral pathogens.

      PubDate: 2017-03-16T18:29:21Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.008
      Issue No: Vol. 249 (2017)
  • Inhibition of Salmonella typhimurium on radish sprouts using nitrogen-cold
    • Authors: Yeong Ji Oh; A Young Song; Sea C. Min
      Pages: 66 - 71
      Abstract: Publication date: Available online 10 March 2017
      Source:International Journal of Food Microbiology
      Author(s): Yeong Ji Oh, A Young Song, Sea C. Min
      This study investigated the effects of cold plasma treatment (CPT) on the inhibition of Salmonella typhimurium on radish sprouts and the quality attributes of the sprouts. Radish sprouts were treated with nitrogen (N2)-cold plasma at 900W and 667Pa for 0, 2, 5, 10, and 20min using a microwave-powered CPT system. The sensory attributes of the radish sprouts, appearance and odor, were evaluated before and after the treatment. The effects of N2-CPT for 10min on microbial growth and the quality attributes of the radish sprouts were evaluated during storage for 12days at 4 and 10°C. N2-CPT at 900W and 667Pa for 20min reduced the number of S. typhimurium by 2.6±0.4logCFU/g. The moisture content of the radish sprouts decreased with treatment time. The appearance and odor of the radish sprouts were not altered by CPT (p >0.05) and this treatment did not affect the quality attributes of the sprouts in terms of color, ascorbic acid concentration, or antioxidant activity during storage at both 4 and 10°C. These findings suggest that CPT has the potential to improve the microbiological safety of radish sprouts with reference to S. typhimurium during cold storage without significant detriment to its quality properties.

      PubDate: 2017-03-16T18:29:21Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.005
      Issue No: Vol. 249 (2017)
  • Methicillin-resistant and -susceptible Staphylococcus aureus from retail
           meat in Denmark
    • Authors: Yuanyue Tang; Jesper Larsen; Jette Kjeldgaard; Paal Skytt Andersen; Robert Skov; Hanne Ingmer
      Pages: 72 - 76
      Abstract: Publication date: 16 May 2017
      Source:International Journal of Food Microbiology, Volume 249
      Author(s): Yuanyue Tang, Jesper Larsen, Jette Kjeldgaard, Paal Skytt Andersen, Robert Skov, Hanne Ingmer
      Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is increasingly related to human infections. Farmers and veterinarians have the highest risk, but infections have also occurred in individuals without prior contact to livestock. Clonal complex (CC) 398 is the predominant LA-MRSA lineage causing human infections, and although pigs are the major source of CC398 worldwide, poultry and other animals are also reservoirs. This raises concern for transmission of MRSA via meat. In this study, the occurrence and characteristics of S. aureus isolated from Danish retail meat were examined with main focus on chicken meat. A total of 145 meat samples from Danish supermarkets were examined, including chicken (Danish, n=102), turkey (non-Danish origin; n=23), and pork (Danish, n=20). S. aureus was detected in 69% of the meat samples. MRSA was detected in 19 meat samples (13%), resulting in MRSA prevalence of 4% of chicken, 52% of turkey, and 15% of pork. Three MRSA positive samples were obtained by direct plating (Brilliance MRSA2), whereas 16 MRSA positive samples were detected only after enrichment (TSB+6.5% NaCl and Brilliance MRSA2). Based on spa typing, 68% of MRSA isolates belonged to CC398 (spa t034, t011, t2582, t108), and hereof one isolate derived from chicken (1%). Further findings were spa type t1430 (CC9) in turkey samples (16%) and the human-associated t008 (CC8) in chicken samples (16%). In conclusion, S. aureus was readily detected in Danish retail meat, but presence of MRSA in chicken meat is rare and it is unlikely to be an important transmission factor of MRSA to humans.

      PubDate: 2017-03-21T16:58:51Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.001
      Issue No: Vol. 249 (2017)
  • A comparative secretome analysis of industrial Aspergillus oryzae and its
           spontaneous mutant ZJGS-LZ-21
    • Authors: Yuanyuan Zhu; Xinle Liang; Hong Zhang; Wei Feng; Ye Liu; Fuming Zhang; Robert J Linhardt
      Pages: 1 - 9
      Abstract: Publication date: 2 May 2017
      Source:International Journal of Food Microbiology, Volume 248
      Author(s): Yuanyuan Zhu, Xinle Liang, Hong Zhang, Wei Feng, Ye Liu, Fuming Zhang, Robert J Linhardt
      Aspergillus oryzae koji plays a crucial role in fermented food products due to the hydrolytic activities of secreted enzymes. In the present study, we performed a comparative secretome analysis of the industrial strain of Aspergillus oryzae 3.042 and its spontaneous mutantZJGS-LZ-21. One hundred and fifty two (152) differential protein spots were excised (p <0.05), and 25 proteins were identified. Of the identified proteins, 91.3% belonged to hydrolytic enzymes acting on carbohydrates or proteins. Consistent with their enzyme activities, the expression of 14 proteins involved in the degradation of cellulose, hemicellulose, starch and proteins, increased in the ZJGS-LZ-21isolate. In particular, increased levels of acid protease (Pep) may favor the degradation of soy proteins in acidic environments and promote the cleavage of allergenic soybean proteins in fermentation, resulting in improvements of product safety and quality. The ZJGS-LZ-21 isolate showed higher protein secretion and increased hydrolytic activities than did strain 3.042, indicating its promising application in soybean paste fermentation.

      PubDate: 2017-02-25T07:31:30Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.003
      Issue No: Vol. 248 (2017)
  • Sourdough-type propagation of faba bean flour: Dynamics of microbial
           consortia and biochemical implications
    • Authors: Rossana Coda; Maryam Kianjam; Erica Pontonio; Michela Verni; Raffaella Di Cagno; Kati Katina; Carlo Giuseppe Rizzello; Marco Gobbetti
      Pages: 10 - 21
      Abstract: Publication date: 2 May 2017
      Source:International Journal of Food Microbiology, Volume 248
      Author(s): Rossana Coda, Maryam Kianjam, Erica Pontonio, Michela Verni, Raffaella Di Cagno, Kati Katina, Carlo Giuseppe Rizzello, Marco Gobbetti
      The microbial ecology of faba bean sourdoughs obtained from an Italian (Ita) and a Finnish (Fi) cultivar, belonging respectively to Vicia faba major and V. faba minor groups, was described by 16S rRNA gene pyrosequencing and culture-dependent analysis. The sourdoughs were propagated with traditional backslopping procedure throughout 14days. Higher microbial diversity was found in the sourdough deriving from V. faba minor (Fi), still containing residual hulls after the milling procedure. After 2days of propagation, the microbial profile of Ita sourdough was characterized by the dominance of the genera Pediococcus, Leuconostoc and Weissella, while the genera Lactococcus, Lactobacillus and Escherichia, as well as Enterobacteriaceae were present in Fi sourdoughs. Yeasts were in very low cell density until the second backslopping and were not anymore found after this time by plate count or pyrosequencing analysis. Among the lactic acid bacteria isolates, Pediococcus pentosaceus, Leuconostoc mesenteroides and Weissella koreensis had the highest frequency of occurrence in both the sourdoughs. Lactobacillus sakei was the only lactobacillus isolated from the first to the last propagation day in Fi sourdough. According to microbiological and acidification properties, the maturity of the sourdoughs was reached after 5days. The presence of hulls and the different microbial composition reflected on biochemical characteristics of Fi sourdoughs, including acidification and phenolic compounds. Moreover, proteolysis in Fi sourdough was more intense compared to Ita. The microbial dynamic of the faba bean sourdoughs showed some differences with the most studied cereal sourdoughs.

      PubDate: 2017-03-04T14:39:21Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.009
      Issue No: Vol. 248 (2017)
  • Persistence of Escherichia coli O157:H7 during pilot-scale processing of
           iceberg lettuce using flume water containing peroxyacetic acid-based
           sanitizers and various organic loads
    • Authors: Gordon R. Davidson; Chelsea N. Kaminski-Davidson; Elliot T. Ryser
      Pages: 22 - 31
      Abstract: Publication date: 2 May 2017
      Source:International Journal of Food Microbiology, Volume 248
      Author(s): Gordon R. Davidson, Chelsea N. Kaminski-Davidson, Elliot T. Ryser
      In order to minimize cross-contamination during leafy green processing, chemical sanitizers are routinely added to the wash water. This study assessed the efficacy of peroxyacetic acid and mixed peracid against E. coli O157:H7 on iceberg lettuce, in wash water, and on equipment during simulated commercial production in a pilot-scale processing line using flume water containing various organic loads. Iceberg lettuce (5.4kg) inoculated to contain 106 CFU/g of a 4-strain cocktail of non-toxigenic, GFP-labeled, ampicillin-resistant E. coli O157:H7, was shredded using a commercial shredder, step-conveyed to a flume tank, washed for 90s using water alone or two different sanitizing treatments (50ppm peroxyacetic acid or mixed peracid) in water containing organic loads of 0, 2.5, 5 or 10% (w/v) blended iceberg lettuce, and then dried using a shaker table and centrifugal dryer. Thereafter, three 5.4-kg batches of uninoculated iceberg lettuce were identically processed. Various product (25g) and water (50ml) samples collected during processing along with equipment surface samples (100cm2) from the flume tank, shaker table and centrifugal dryer were then assessed for numbers of E. coli O157:H7. Organic load rarely impacted (P >0.05) the efficacy of either peroxyacetic acid or mixed peracid, with typical reductions of >5logCFU/ml in wash water throughout processing for all organic loads. Increases in organic load in the wash water corresponded to changes in total solids, chemical oxygen demand, turbidity, maximum filterable volume, and oxidation/reduction potential. After 90s of exposure to flume water, E. coli O157:H7 reductions on inoculated lettuce ranged from 0.97 to 1.74logCFU/g using peroxyacetic acid, with an average reduction of 1.35logCFU/g for mixed peracid. E. coli O157:H7 persisted on all previously uninoculated lettuce following the inoculated batch, emphasizing the need for improved intervention strategies that can better ensure end-product safety.

      PubDate: 2017-02-25T07:31:30Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.006
      Issue No: Vol. 248 (2017)
  • Biocontrol of Monilinia laxa by Aureobasidium pullulans strains: Insights
           on competition for nutrients and space
    • Authors: Alessandra Di Francesco; Luisa Ugolini; Salvatore D'Aquino; Eleonora Pagnotta; Marta Mari
      Pages: 32 - 38
      Abstract: Publication date: 2 May 2017
      Source:International Journal of Food Microbiology, Volume 248
      Author(s): Alessandra Di Francesco, Luisa Ugolini, Salvatore D'Aquino, Eleonora Pagnotta, Marta Mari
      Two Aureobasidium pullulans strains (L1 and L8), able to prevent postharvest fruit decay, were evaluated in order to elucidate how the competition for nutrients and space was involved in their activity against Monilinia laxa, the causal agent of peach brown rot. The competition for nutrients was studied by co-culturing pathogen conidia and antagonists in different conditions of nutrient availability and avoiding contact between them. Both antagonists prevented the germination of conidia of M. laxa in water, reducing germination rate by >35%. However, L1 and L8 showed the lowest inhibition of conidial germination in peach juice at 5%, with a reduction of 12.6% and 13.9% respectively. HPLC amino acid analysis of peach juice revealed that the addition of the yeast suspension greatly modified their composition: asparagine was completely depleted soon after 12h of incubation and was probably hydrolyzed to aspartic acid by the yeasts, as aspartic acid content markedly increased. Pure asparagine and aspartic acid were tested by in vitro trials at the concentrations found in peach juice: both influenced M. laxa growth, but in opposite ways. Asparagine stimulated pathogen growth; conversely, amended medium with aspartic acid significantly inhibited the conidia germination and mycelial development of M. laxa. Scanning Electron Microscopy revealed that both strains showed a great capability to compete with M. laxa for space (starting 8h after treatment), colonizing the wound surface and inhibiting pathogen growth. This study clearly showed that A. pullulans L1 and L8 strains could compete with M. laxa for nutrients and space; this mode of action may play an important role in the antagonistic activity, especially in the first hours of tritrophic host-pathogen-antagonist interaction, although several other mechanisms can interact each other.

      PubDate: 2017-03-04T14:39:21Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.007
      Issue No: Vol. 248 (2017)
  • Nondairy beverage produced by controlled fermentation with potential
           probiotic starter cultures of lactic acid bacteria and yeast
    • Authors: Ana Luiza Freire; Cintia Lacerda Ramos; Patrícia Nirlane da Costa Souza; Mauro Guilherme Barros Cardoso; Rosane Freitas Schwan
      Pages: 39 - 46
      Abstract: Publication date: 2 May 2017
      Source:International Journal of Food Microbiology, Volume 248
      Author(s): Ana Luiza Freire, Cintia Lacerda Ramos, Patrícia Nirlane da Costa Souza, Mauro Guilherme Barros Cardoso, Rosane Freitas Schwan
      This work aimed to develop a nondairy fermented beverage from a blend of cassava and rice based on Brazilian indigenous beverage cauim using probiotic lactic acid bacteria (LAB) and yeast. The indigenous strains Lactobacillus plantarum CCMA 0743 (from cauim) and Torulaspora delbrueckii CCMA 0235 (from tarubá), and the commercial probiotic, L. acidophilus LAC-04, were used as starter cultures in single and co-cultivations. The bacteria populations were around 8.0 log (CFU/mL) at the end of all fermentations as recommended for probiotic products. Higher residual starch contents were noted in the single LAB cultures (10.6% [w/w]) than in co-cultures (<6% [w/w]), showing that co-culture may help the digestibility. For all different assays (single and co-culture), lactic acid was the main organic acid detected (>1.6g/L) and ethanol was lower than 0.5% (w/v) consisting in a non-alcoholic beverage. The assays containing yeast showed the highest antioxidant activity (around 10% by DPPH and ABTS methods). Therefore, a nondairy fermented beverage was successfully obtained, and the co-culture of LAB and T. delbrueckii could increase the product's functional properties.

      PubDate: 2017-02-25T07:31:30Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.011
      Issue No: Vol. 248 (2017)
  • Action mechanisms involved in the bioprotective effect of Lactobacillus
           harbinensis K.V9.3.1.Np against Yarrowia lipolytica in fermented milk
    • Authors: Sophie Mieszkin; Nolwenn Hymery; Stella Debaets; Emmanuel Coton; Gwenaelle Le Blay; Florence Valence; Jérôme Mounier
      Pages: 47 - 55
      Abstract: Publication date: 2 May 2017
      Source:International Journal of Food Microbiology, Volume 248
      Author(s): Sophie Mieszkin, Nolwenn Hymery, Stella Debaets, Emmanuel Coton, Gwenaelle Le Blay, Florence Valence, Jérôme Mounier
      The use of lactic acid bacteria (LAB) as bioprotective cultures can be an alternative to chemical preservatives or antibiotic to prevent fungal spoilage in dairy products. Among antifungal LAB, Lactobacillus harbinensis K.V9.3.1Np showed a remarkable antifungal activity for the bioprotection of fermented milk without modifying their organoleptic properties (Delavenne et al., 2015). The aim of the present study was to elucidate the action mechanism of this bioprotective strain against the spoilage yeast Yarrowia lipolytica. To do so, yeast viability, membrane potential, intracellular pH (pHi) and reactive oxygen species (ROS) production were assessed using flow cytometry analyses after 3, 6 and 10days incubation in cell-free supernatants. The tested supernatants were obtained after milk fermentation with yogurt starter cultures either in co-culture with L. harbinensis K.V9.3.1Np (active supernatant) or not (control supernatant). Scanning-electron microscopy (SEM) was used to monitor yeast cell morphology and 9 known antifungal organic acids were quantified in both yogurt supernatants using high-performance liquid chromatograph (HPLC). Yeast growth occurred within 3days incubation in control supernatant, while it was prevented for up to 10days by the active supernatant. Interestingly, between 66 and 99% of yeast cells were under a viable but non-cultivable (VNC) state despite an absence of membrane integrity loss. While ROS production was not increased in active supernatant, cell physiological changes including membrane depolarization and pHi decrease were highlighted. Moreover, morphological changes including membrane collapsing and cell lysis were observed. These effects could be attributed to the synergistic action of organic acids. Indeed, among the 8 organic acids quantified in active supernatant, five of them (acetic, lactic, 2-pyrrolidone-5-carboxylic, hexanoic and 2-hydroxybenzoic acids) were at significantly higher concentrations in the active supernatant than in the control one. In conclusion, this study has provided new information on the physiological mechanisms induced by an antifungal LAB that could be used as part of the hurdle technology to prevent fungal spoilage in dairy products.

      PubDate: 2017-04-05T10:06:35Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.013
      Issue No: Vol. 248 (2017)
  • Lactic acid fermentation drives the optimal volatile flavor-aroma profile
           of pomegranate juice
    • Authors: Raffaella Di Cagno; Pasquale Filannino; Marco Gobbetti
      Pages: 56 - 62
      Abstract: Publication date: 2 May 2017
      Source:International Journal of Food Microbiology, Volume 248
      Author(s): Raffaella Di Cagno, Pasquale Filannino, Marco Gobbetti
      Pomegranate juice (PJ) fermented with Lactobacillus plantarum C2, POM1, and LP09, unstarted-PJ, and raw-PJ were characterized for the profile of the volatile components (VOC) by PT–GC–MS. Lactic acid fermentation through selected strains enhanced the flavor profile of PJ. Concentrations of desired compounds (e.g., alcohols, ketones, and terpenes) were positively affected, whereas those of non-desired aldehydes decreased. Unstarted-PJ mainly differentiated from fermented PJs for the highest levels of aldehydes and sulfur compounds, and in lesser extent of furans, whereas alcohols, ketones, and alkenes followed by terpenes and benzene derivatives mainly differentiated fermented PJs. As expected, the lowest level of VOC was found in raw-PJ. VOC profile reflected on the sensory features of fermented PJs, unstarted-PJ, and raw-PJ, which were evaluated using a consensus modified flavor profile based on 13 attributes. Fermented PJs were mainly discriminated by the higher intensity of floral, fruity and anise notes than the controls.

      PubDate: 2017-03-04T14:39:21Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.014
      Issue No: Vol. 248 (2017)
  • In situ synthesis of exopolysaccharides by Leuconostoc spp. and Weissella
           spp. and their rheological impacts in fava bean flour
    • Authors: Yan Xu; Yaqin Wang; Rossana Coda; Elina Säde; Päivi Tuomainen; Maija Tenkanen; Kati Katina
      Pages: 63 - 71
      Abstract: Publication date: 2 May 2017
      Source:International Journal of Food Microbiology, Volume 248
      Author(s): Yan Xu, Yaqin Wang, Rossana Coda, Elina Säde, Päivi Tuomainen, Maija Tenkanen, Kati Katina
      Fava bean flour is regarded as a potential plant-based protein source, but the addition of it at high concentration is restricted by its poor texture-improving ability and by anti-nutritional factors (ANF). Exopolysaccharides (EPS) produced by lactic acid bacteria (LAB) are regarded as good texture modifiers. In this study, fava bean flour was fermented with Leuconostoc spp. and Weissella spp. with or without sucrose addition, in order to evaluate their potential in EPS production. The contents of free sugars, organic acids, mannitol and EPS in all fermented fava bean doughs were measured. Rheological properties of sucrose-enriched doughs, including viscosity flow curves, hysteresis loop and dynamic oscillatory sweep curves, were measured after fermentation. As one of the ANF, the degradation of raffinose family oligosaccharides (RFO) was also studied by analyzing RFO profiles of different doughs. Quantification of EPS revealed the potential of Leuconostoc pseudomesenteroides DSM 20193 in EPS production, and the rheological analysis showed that the polymers produced by this strain has the highest thickening and gelling capability. Furthermore, the viscous fava bean doughs containing plant proteins and synthesized in situ EPS may have a potential application in the food industry and fulfill consumers' increasing demands for “clean labels” and plant-originated food materials.

      PubDate: 2017-03-04T14:39:21Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.012
      Issue No: Vol. 248 (2017)
  • Characterization of extended-spectrum β-lactamases (ESBLs)-producing
           Salmonella in retail raw chicken carcasses
    • Authors: Jing Qiao; Qiang Zhang; Walid Q. Alali; Jiawei Wang; Lingyuan Meng; Yingping Xiao; Hua Yang; Sheng Chen; Shenghui Cui; Baowei Yang
      Pages: 72 - 81
      Abstract: Publication date: 2 May 2017
      Source:International Journal of Food Microbiology, Volume 248
      Author(s): Jing Qiao, Qiang Zhang, Walid Q. Alali, Jiawei Wang, Lingyuan Meng, Yingping Xiao, Hua Yang, Sheng Chen, Shenghui Cui, Baowei Yang
      Extended-spectrum β-lactamases (ESBLs)-producing Salmonella is considered a serious concern to public health worldwide. However, limited information is available on ESBLs-producing Salmonella in retail chicken products in China. The objective of this study was to characterize ESBLs-producing Salmonella isolates from retail chickens in China. A total of 890 Salmonella isolates from retail chicken carcasses collected from 4 provinces were firstly screened for ESBLs-production phenotype via the double-disk synergy test method. A total of 96 (10.8%, n=890) ESBLs-producing Salmonella were identified and subjected to PFGE analysis, characterization for the presence of ESBLs encoding genes, transposons, carbapenemase and virulence genes. A total of 59 PFGE profiles were detected in these 96 isolates, among which 57.3% were found to harbor bla TEM-1, whereas 30.2%, 24.0%, 18.8% and 7.3% were carrying bla OXA-1, bla CTX-M-15, bla CTX-M-3 and bla PSE-1 genes, respectively. Moreover, 42 (43.8%) isolates co-carried 2 ESBLs-producing genes, and two (2.1%) isolates co-carried 3 genes. Furthermore, 24 (25.0%) ESBLs-producing isolates carried VIM and 10 (10.4%) carried KPC encoding genes that closely associated with carbapenems resistance. Eighty-eight isolates harbored transposons ranging from 4.2% for Tn903 to 76.0% for Tn21. Out of the 88 Salmonella that harbored transposons, 25%, 22.7%, 23.9%, 10.2% and 1.1% of isolates were found to carry 2, 3, 4, 5 and 6 transposons, respectively. The minimum inhibitory concentration (MIC) values for cephalosporins (ceftriaxone, cefoperazone and cefoxitin) to ESBLs-producing isolates were from 4 to 1024μg/mL, for nalidixic acid were from 64 to 512μg/mL, for fluoroquinolones (ciprofloxacin, levofloxacin and gatifloxacin) were from 4 to 256μg/mL. Twenty-nine virulence genes were detected in the 96 ESBLs-producing isolates with 2.1% harbored spvR (lowest) and 90.6% harbored marT and steB (highest). All isolates carried at least one virulence gene, 83.3% of the isolates co-carried ≥10, 17.7% co-carried ≥15, and 1.0% co-carried 23 virulence genes. Interestingly, 16.7% of the isolates resistant to >12 antibiotics tested and shown to carry >4 transposons and 10 virulence genes. Our findings indicated that ESBLs-producing Salmonella isolated from retail chicken meat in China were highly resistant to antibiotics, frequently harbored transposons, virulence genes, carbapenems hydrolysis enzymes and ESBLs encoding genes. These isolates can pose a significant public health risk.
      Graphical abstract image

      PubDate: 2017-04-05T10:06:35Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.016
      Issue No: Vol. 248 (2017)
  • Listeria monocytogenes ability to survive desiccation: Influence of
           serotype, origin, virulence, and genotype
    • Authors: Fiona Zoz; Cosette Grandvalet; Emilie Lang; Cyril Iaconelli; Patrick Gervais; Olivier Firmesse; Stéphane Guyot; Laurent Beney
      Pages: 82 - 89
      Abstract: Publication date: 2 May 2017
      Source:International Journal of Food Microbiology, Volume 248
      Author(s): Fiona Zoz, Cosette Grandvalet, Emilie Lang, Cyril Iaconelli, Patrick Gervais, Olivier Firmesse, Stéphane Guyot, Laurent Beney
      Listeria monocytogenes, a bacterium that is responsible for listeriosis, is a very diverse species. Desiccation resistance has been rarely studied in L. monocytogenes, although it is a stress that is largely encountered by this microorganism in food-processing environments and that could be managed to prevent its presence. The objective of this study was to evaluate the resistance of 30 L. monocytogenes strains to moderate desiccation (75% relative humidity) and evaluate the correlation of such resistance with the strains' virulence, serotype and genotype. The results showed a great heterogeneity of strains regarding their ability to survive (loss of cultivability between 0.4 and 2.0 log). Strains were classified into three groups according to desiccation resistance (sensitive, intermediate, or resistant), and the strain repartition was analyzed relative to serotype, virulence level and environmental origin of the strains. No correlation was found between isolate origin and desiccation resistance. All serotype 1/2b strains were classified into the group of resistant strains. Virulent and hypovirulent strains were distributed among the three groups of desiccation resistance. Finally, a genomic comparison was performed based on 31 genes that were previously identified as being involved in desiccation resistance. The presence of those genes was localized among the genomes of some strains and compared regarding strain-resistance levels. High nucleotide conservation was identified between resistant and desiccation-sensitive strains. In conclusion, the findings regarding the strains of serotype 1/2b indicate potential serotype-specific resistance to desiccation, and thus, to relative humidity fluctuations potentially encountered in food-related environments. The genomic comparison of 31 genes associated to desiccation tolerance did not reveal differences among four strains which have different level of resistance to desiccation.

      PubDate: 2017-03-16T18:29:21Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.010
      Issue No: Vol. 248 (2017)
  • Inside Front Cover - Editorial Board
    • Abstract: Publication date: 16 May 2017
      Source:International Journal of Food Microbiology, Volume 249

      PubDate: 2017-04-26T16:47:26Z
  • ICFMH Announcment
    • Abstract: Publication date: 16 May 2017
      Source:International Journal of Food Microbiology, Volume 249

      PubDate: 2017-04-26T16:47:26Z
  • Two complementary approaches to quantify variability in heat resistance of
           spores of Bacillus subtilis
    • Authors: Heidy M.W. den Besten; Erwin M. Berendsen; Marjon H.J. Wells-Bennik; Han Straatsma; Marcel H. Zwietering
      Abstract: Publication date: Available online 26 April 2017
      Source:International Journal of Food Microbiology
      Author(s): Heidy M.W. den Besten, Erwin M. Berendsen, Marjon H.J. Wells-Bennik, Han Straatsma, Marcel H. Zwietering
      Realistic prediction of microbial inactivation in food requires quantitative information on variability introduced by the microorganisms. Bacillus subtilis forms heat resistant spores and in this study the impact of strain variability on spore heat resistance was quantified using 20 strains. In addition, experimental variability was quantified by using technical replicates per heat treatment experiment, and reproduction variability was quantified by using two biologically independent spore crops for each strain that were heat treated on different days. The fourth-decimal reduction times and z-values were estimated by a one-step and two-step model fitting procedure. Grouping of the 20 B. subtilis strains into two statistically distinguishable groups could be confirmed based on their spore heat resistance. The reproduction variability was higher than experimental variability, but both variabilities were much lower than strain variability. The model fitting approach did not significantly affect the quantification of variability. Remarkably, when strain variability in spore heat resistance was quantified using only the strains producing low-level heat resistant spores, then this strain variability was comparable with the previously reported strain variability in heat resistance of vegetative cells of Listeria monocytogenes, although in a totally other temperature range. Strains that produced spores with high-level heat resistance showed similar temperature range for growth as strains that produced low-level heat resistance. Strain variability affected heat resistance of spores most, and therefore integration of this variability factor in modelling of spore heat resistance will make predictions more realistic.

      PubDate: 2017-04-26T16:47:26Z
      DOI: 10.1016/j.ijfoodmicro.2017.04.014
  • Headspace oxygen as a hurdle to improve the safety of in-pack pasteurized
           chilled food during storage at different temperatures
    • Authors: Nydia Munoz; Kanishka Bhunia; Hongchao Zhang; Gustavo V. Barbosa-Cánovas; Juming Tang; Shyam Sablani
      Abstract: Publication date: Available online 26 April 2017
      Source:International Journal of Food Microbiology
      Author(s): Nydia Munoz, Kanishka Bhunia, Hongchao Zhang, Gustavo V. Barbosa-Cánovas, Juming Tang, Shyam Sablani
      This study investigated the use of headspace oxygen in a model food system to prevent the growth of anaerobic pathogenic bacteria in in-pack pasteurized food at various storage temperatures. Three model food formulations prepared with tryptic soy broth and three agar concentrations (0.1, 0.4 and 1.0%) were sealed without removing the air from the package in high oxygen barrier pouches (OTR=0.3cm3/m2·day·atm). Important properties influencing bacterial growth, including pH and water activity (aw) were determined. The oxygen sorption kinetics of each model food were obtained at three different storage temperatures (8, 12, and 20°C) using an OxySense Gen III 300 system. An analytical solution of Fick's second law was used to determine the O2 diffusion coefficient. Growth challenge studies at 12 and 20°C were conducted at three selected locations (top, center and bottom layers) in model foods containing 1% agar. Model foods were inoculated with Clostridium sporogenes PA 3679 (300spores/mL), and were classified as low-acid (pH>4.5, aw >0.85). When the storage temperature decreased from 20 to 8°C, the oxygen diffusion decreased from 0.82×10−9 m2/s to 0.68×10−9 m2/s. As the agar concentration was increased from 0.1 to 1.0%, the effective oxygen permeability decreased significantly (p =0.007) from 0.88×10−9 m2/s to 0.65×10−9 m2/s. When the inoculated model foods were stored at 12°C for 14days, C. sporogenes PA 3679 was unable to grow. As the storage temperature was increased to 20°C, significant bacterial growth was observed with storage time (p <0.0001), and the C. sporogenes PA 3679 population increased by around 6logCFU/g. However, the location of the food did not influence the growth distribution of C. sporogenes PA 3679. These results demonstrate that oxygen diffusion from the pouch headspace was primarily limited to the food surface. Findings suggest that the air/oxygen present in the package headspace may not be considered as a food safety hurdle in the production of pasteurized packaged food.

      PubDate: 2017-04-26T16:47:26Z
      DOI: 10.1016/j.ijfoodmicro.2017.04.018
  • A novel typing method for Listeria monocytogenes using high-resolution
           melting analysis (HRMA) of tandem repeat regions
    • Authors: Chihiro Ohshima; Hajime Takahashi; Ai Iwakawa; Takashi Kuda; Bon Kimura
      Abstract: Publication date: Available online 25 April 2017
      Source:International Journal of Food Microbiology
      Author(s): Chihiro Ohshima, Hajime Takahashi, Ai Iwakawa, Takashi Kuda, Bon Kimura
      Listeria monocytogenes, which is responsible for causing food poisoning known as listeriosis, infects humans and animals. Widely distributed in the environment, this bacterium is known to contaminate food products after being transmitted to factories via raw materials. To minimize the contamination of products by food pathogens, it is critical to identify and eliminate factory entry routes and pathways for the causative bacteria. High resolution melting analysis (HRMA) is a method that takes advantage of differences in DNA sequences and PCR product lengths that are reflected by the disassociation temperature. Through our research, we have developed a multiple locus variable-number tandem repeat analysis (MLVA) using HRMA as a simple and rapid method to differentiate L. monocytogenes isolates. While evaluating our developed method, the ability of MLVA-HRMA, MLVA using capillary electrophoresis, and multilocus sequence typing (MLST) was compared for their ability to discriminate between strains. The MLVA-HRMA method displayed greater discriminatory ability than MLST and MLVA using capillary electrophoresis, suggesting that the variation in the number of repeat units, along with mutations within the DNA sequence, was accurately reflected by the melting curve of HRMA. Rather than relying on DNA sequence analysis or high-resolution electrophoresis, the MLVA-HRMA method employs the same process as PCR until the analysis step, suggesting a combination of speed and simplicity. The result of MLVA-HRMA method is able to be shared between different laboratories. There are high expectations that this method will be adopted for regular inspections at food processing facilities in the near future.

      PubDate: 2017-04-26T16:47:26Z
      DOI: 10.1016/j.ijfoodmicro.2017.04.015
  • Abiotic conditions leading to FUM gene expression and fumonisin
           accumulation by Fusarium proliferatum strains grown on a wheat-based
    • Authors: Eugenia Cendoya; Laetitia Pinson-Gadais; María C. Farnochi; María L. Ramirez; Sylvain Chéreau; Giselè Marcheguay; Christine Ducos; Christian Barreau; Florence Richard-Forget
      Abstract: Publication date: Available online 25 April 2017
      Source:International Journal of Food Microbiology
      Author(s): Eugenia Cendoya, Laetitia Pinson-Gadais, María C. Farnochi, María L. Ramirez, Sylvain Chéreau, Giselè Marcheguay, Christine Ducos, Christian Barreau, Florence Richard-Forget
      Fusarium proliferatum produces fumonisins B not only on maize but also on diverse crops including wheat. Using a wheat-based medium, the effects of abiotic factors, temperature and water activity (aW), on growth, fumonisin biosynthesis, and expression of FUM genes were compared for three F. proliferatum strains isolated from durum wheat in Argentina. Although all isolates showed similar profiles of growth, the fumonisin production profiles were slightly different. Regarding FUM gene transcriptional control, both FUM8 and FUM19 expression showed similar behavior in all tested conditions. For both genes, expression at 25°C correlated with fumonisin production, irrespective of the aw conditions. However, at 15°C, these two genes were as highly expressed as at 25°C although the amounts of toxin were very weak, suggesting that the kinetics of fumonisin production was slowed at 15°C. This study provides useful baseline data on conditions representing a low or a high risk for contamination of wheat kernels with fumonisins.

      PubDate: 2017-04-26T16:47:26Z
      DOI: 10.1016/j.ijfoodmicro.2017.04.017
  • Effects of meat juice on biofilm formation of Campylobacter and Salmonella
    • Authors: Jiaqi Li; Jinsong Feng; Lina Ma; César de la Fuente Núñez; Greta Gölz; Xiaonan Lu
      Abstract: Publication date: Available online 24 April 2017
      Source:International Journal of Food Microbiology
      Author(s): Jiaqi Li, Jinsong Feng, Lina Ma, César de la Fuente Núñez, Greta Gölz, Xiaonan Lu
      Campylobacter and Salmonella are leading causes of foodborne illnesses worldwide, vastly harboured by raw meat as their common food reservoir. Both microbes are prevalent in meat processing environments in the form of biofilms that contribute to cross-contamination and foodborne infection. This study applied raw meat juice (chicken juice and pork juice) as a minimally processed food model to study its effects on bacterial biofilm formation. Meat juice was collected during the freeze-thaw process of raw meat and sterilized by filtration. In 96-well polystyrene plates and glass chambers, supplementation of over 25% meat juice (v/v) in laboratory media led to an increase in biofilm formation of Campylobacter and Salmonella. During the initial attachment stage of biofilm development, more bacterial cells were present on surfaces treated with meat juice residues compared to control surfaces. Meat juice particulates on abiotic surfaces facilitated biofilm formation of Campylobacter and Salmonella under both static and flow conditions, with the latter being assessed using a microfluidic platform. Further, the deficiency in biofilm formation of selected Campylobacter and Salmonella mutant strains was restored in the presence of meat juice particulates. These results suggested that meat juice residues on the abiotic surfaces might act as a surface conditioner to support initial attachment and biofilm formation of Campylobacter and Salmonella. This study sheds light on a possible survival mechanism of Campylobacter and Salmonella in meat processing environments, and indicates that thorough cleaning of meat residues during meat production and handling is critical to reduce the bacterial load of Campylobacter and Salmonella.

      PubDate: 2017-04-26T16:47:26Z
      DOI: 10.1016/j.ijfoodmicro.2017.04.013
  • ICFMH Announcment
    • Abstract: Publication date: 2 May 2017
      Source:International Journal of Food Microbiology, Volume 248

      PubDate: 2017-04-05T10:06:35Z
  • Adsorption of aflatoxin B1, zearalenone and ochratoxin A by microorganisms
           isolated from Kefir grains
    • Authors: Fadia Ben Taheur; Kais Fedhila; Kamel Chaieb; Bochra Kouidhi; Amina Bakhrouf; Luís Abrunhosa
      Abstract: Publication date: Available online 28 March 2017
      Source:International Journal of Food Microbiology
      Author(s): Fadia Ben Taheur, Kais Fedhila, Kamel Chaieb, Bochra Kouidhi, Amina Bakhrouf, Luís Abrunhosa
      A strategy to reduce the deleterious effects of mycotoxins is to use dietary supplements that contain microorganisms that bind mycotoxins and diminish their gastrointestinal absorption. Novel strains were isolated from a Kefir culture and assessed for their mycotoxin adsorption and biotransformation ability. The most active strains were identified using DNA sequencing, and the stability of microorganism/mycotoxin complexes was evaluated using buffer solutions to simulate the pH conditions in the gastrointestinal tract. Our results showed that the microorganism consortium of Kefir grains adsorbed 82 to 100% of aflatoxin B1 (AFB1), zearalenone (ZEA) and ochratoxin A (OTA) when cultivated in milk. The main strains that were capable of mycotoxin adsorption were identified as Lactobacillus kefiri, Kazachstania servazzii and Acetobacter syzygii. The strain L. kefiri KFLM3 was the most active, adsorbing 80 to 100% of the studied mycotoxins when cultivated in milk. Nonetheless, the strain K. servazzii KFGY7 retained more mycotoxin after the desorption experiments (65, 69 and 67% for AFB1, OTA and ZEA, respectively). These findings suggest that Kefir consumption may help to reduce gastrointestinal absorption of these mycotoxins and consequently reduce their toxic effects. The isolated strains may be of interest for the development of fermented dairy products for human consumption that have a new probiotic characteristic, the adsorption of mycotoxins.

      PubDate: 2017-03-28T17:12:16Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.021
  • Prevalence, antimicrobial resistance and multiple-locus variable-number
           tandem-repeat analysis profiles of diarrheagenic Escherichia coli isolated
           from different retail foods
    • Authors: Lili Wang; Hiromi Nakamura; Eriko Kage-Nakadai; Yukiko Hara-Kudo; Yoshikazu Nishikawa
      Abstract: Publication date: Available online 7 March 2017
      Source:International Journal of Food Microbiology
      Author(s): Lili Wang, Hiromi Nakamura, Eriko Kage-Nakadai, Yukiko Hara-Kudo, Yoshikazu Nishikawa
      Diarrheagenic E. coli (DEC) isolates were recovered from local retail markets and the Osaka Municipal Central Wholesale Market in Japan. Retail food samples were collected for analysis in Osaka Japan from 2005 to 2008 and consisted of 32 beef, 28 pork, 20 poultry, 136 fish, 66 fruits and vegetables and 51 ready–to-eat (RTE) food samples. A total of 82 DEC strains were recovered from 64 (19%) food samples with the highest prevalence in poultry (100%, 20/20), followed by pork (54%, 15/28), beef (28%, 9/32), fruits and vegetables (12%, 8/66), fish (6.6%, 9/136) and RTE foods (5.9%, 3/51). Most of the strains belonged to E. coli possessing the enteroaggregative E. coli (EAEC) heat-stable enterotoxin 1 (EAST1) gene (EAST1EC; n =62, P <0.0001) and enteropathogenic E. coli (EPEC; n =16, P <0.01), whereas only 1 strain belonged to Shiga toxin-producing E. coli (STEC), 1 to EAEC and 2 to enterotoxigenic E. coli (ETEC) strains. Of the 82 DEC isolates, 22 O and 13H serogroups were detected, including some specific serogroups (O91, O103, O115, O119, O126, and O157) which have been associated with human diarrheal infections. Phylogenetic group A and B1 were predominant among the DEC isolates. Antimicrobial resistance to tetracycline was most common (49%), followed by nalidixic acid (28%), ampicillin (24%), sulfamethoxazole/trimethoprim (20%), and cephalothin (18%). All isolates were susceptible to aztreonam. Of the resistant strains, 44% (22/50) demonstrated resistance to >3 antimicrobial agents. Isolates resistant to >5 antimicrobials were only found in the meat samples, while isolates from the fruits and vegetables as well as RTE foods showed resistance to only 1 or 2 antimicrobial agents. Sixty one percent of EAST1EC, 56% of EPEC and all of the EAEC and ETEC were resistant to at least 1 antimicrobial agent. Multiple-locus variable-number tandem repeat analysis (MLVA) was used in this study for genotyping of DEC. The 82 isolates collected for this study showed 77 distinct MLVA profiles located among 3 branches. The Simpson's Index of Diversity (D) was 99.9% at its highest. The high diversity of these food strains would suggest their originating from a variety of sources and environments. In conclusion, retail food samples in Japan were contaminated with DEC; EAST1EC, a putative DEC, were detected at high rates in poultry, pork and beef. Isolates resistant to >3 antimicrobials were found only in raw meat and fish. Food animals may act as the reservoir for multi-resistant bacteria. Due to the finding that nearly 1/3 of EAST1EC strains were resistant to >3 antimicrobials, additional surveillance for EAST1EC should be initiated.

      PubDate: 2017-03-09T14:44:54Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.003
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