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MICROBIOLOGY (254 journals)                  1 2     

Showing 1 - 0 of 0 Journals sorted alphabetically
Acta Microbiologica et Immunologica Hungarica     Full-text available via subscription   (Followers: 5)
Addiction Genetics     Open Access   (Followers: 5)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 16)
Advances in Microbiology     Open Access   (Followers: 17)
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: 17)
American Journal of Microbiological Research     Open Access   (Followers: 2)
American Journal of Microbiology     Open Access   (Followers: 13)
American Journal of Molecular Biology     Open Access   (Followers: 2)
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: 34)
Antimicrobial Agents and Chemotherapy     Hybrid Journal   (Followers: 21)
Antiviral Research     Hybrid Journal   (Followers: 7)
Applied and Environmental Microbiology     Hybrid Journal   (Followers: 39)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 17)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 58)
Aquatic Microbial Ecology     Hybrid Journal   (Followers: 2)
Archives of Microbiology     Hybrid Journal   (Followers: 7)
Avicenna Journal of Clinical Microbiology and Infection     Open Access   (Followers: 1)
Bangladesh Journal of Medical Microbiology     Open Access  
Beneficial Microbes     Full-text available via subscription   (Followers: 2)
Bio-Research     Full-text available via subscription  
BioArchitecture     Full-text available via subscription  
Bioethanol     Open Access  
Biomaterials Science     Full-text available via subscription   (Followers: 8)
BioMolecular Concepts     Hybrid Journal   (Followers: 2)
Biomolecular Detection and Quantification     Open Access  
Biomolecules     Open Access   (Followers: 1)
Biotechnology and Molecular Biology Reviews     Open Access  
BMC Microbiology     Open Access   (Followers: 8)
Brazilian Journal of Microbiology     Open Access   (Followers: 2)
Canadian Journal of Infectious Diseases and Medical Microbiology     Open Access   (Followers: 2)
Canadian Journal of Microbiology     Full-text available via subscription   (Followers: 3)
Cell Biology : Research & Therapy     Hybrid Journal   (Followers: 3)
Cell Host & Microbe     Full-text available via subscription   (Followers: 14)
Cell Medicine     Open Access   (Followers: 3)
Cell Regeneration     Open Access   (Followers: 1)
Cell Stem Cell     Full-text available via subscription   (Followers: 32)
CellBio     Open Access  
Cells     Open Access   (Followers: 1)
Cellular & Molecular Immunology     Hybrid Journal   (Followers: 11)
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: 16)
Clinical Microbiology Newsletter     Hybrid Journal   (Followers: 4)
Clinical Microbiology Reviews     Hybrid Journal   (Followers: 16)
Comparative Immunology, Microbiology and Infectious Diseases     Hybrid Journal   (Followers: 10)
Computational Molecular Bioscience     Open Access   (Followers: 1)
Critical Reviews in Microbiology     Hybrid Journal   (Followers: 11)
Current Clinical Microbiology Reports     Hybrid Journal   (Followers: 1)
Current Issues in Molecular Biology     Open Access   (Followers: 2)
Current Microbiology     Hybrid Journal   (Followers: 9)
Current Molecular Biology Reports     Hybrid Journal   (Followers: 1)
Current Molecular Imaging     Hybrid Journal  
Current Opinion in Microbiology     Hybrid Journal   (Followers: 29)
Current Tissue Engineering     Hybrid Journal   (Followers: 2)
Current Topics in Microbiology and Immunology     Hybrid Journal   (Followers: 8)
Diagnostic Microbiology and Infectious Disease     Hybrid Journal   (Followers: 8)
Disease and Molecular Medicine     Open Access   (Followers: 1)
DNA Barcodes     Open Access  
Egyptian Journal of Biochemistry and Molecular Biology     Full-text available via subscription  
Emerging Microbes & Infections     Open Access   (Followers: 2)
Environmental Microbiology     Hybrid Journal   (Followers: 13)
Environmental Microbiology Reports     Hybrid Journal   (Followers: 3)
Enzyme and Microbial Technology     Hybrid Journal   (Followers: 12)
Epigenetics of Degenerative Diseases     Open Access   (Followers: 5)
European Journal of Clinical Microbiology & Infectious Diseases     Hybrid Journal   (Followers: 17)
European Journal of Microbiology and Immunology     Open Access   (Followers: 8)
Experimental and Molecular Pathology     Hybrid Journal   (Followers: 4)
Experimental Cell Research     Hybrid Journal   (Followers: 7)
Fems Microbiology Ecology     Hybrid Journal   (Followers: 8)
Fems Microbiology Letters     Hybrid Journal   (Followers: 18)
Fems Microbiology Reviews     Hybrid Journal   (Followers: 23)
Fermentation     Open Access   (Followers: 1)
Folia Histochemica et Cytobiologica     Open Access  
Folia Microbiologica     Hybrid Journal   (Followers: 1)
Food Microbiology     Hybrid Journal   (Followers: 15)
Frontiers in Cell and Developmental Biology     Open Access   (Followers: 3)
Frontiers in Cellular and Infection Microbiology     Open Access   (Followers: 3)
Frontiers in Cellular Neuroscience     Open Access   (Followers: 6)
Frontiers in Microbiology     Open Access   (Followers: 8)
Frontiers in Molecular Neuroscience     Open Access   (Followers: 3)
Future Microbiology     Hybrid Journal   (Followers: 4)
Future Virology     Hybrid Journal   (Followers: 7)
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: 2)
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: 7)
International Journal of Molecular Medicine     Full-text available via subscription   (Followers: 5)
International Journal of Mycobacteriology     Open Access  
International Journal of Systematic and Evolutionary Microbiology     Full-text available via subscription   (Followers: 3)
International Journal of Virology and Molecular Biology     Open Access  
International Microbiology     Open Access   (Followers: 3)
Invertebrate Immunity     Open Access   (Followers: 1)
JMM Case Reports     Open Access  
Journal of Cell Science & Therapy     Open Access   (Followers: 2)
Journal of Microbial & Biochemical Technology     Open Access   (Followers: 1)
Journal of Applied Biology & Biotechnology     Open Access   (Followers: 1)
Journal of Applied Microbiology     Hybrid Journal   (Followers: 11)
Journal of Bacteriology     Hybrid Journal   (Followers: 27)
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 Brewing and Distilling     Open Access   (Followers: 1)
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: 28)
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: 3)
Journal of General and Molecular Virology     Open Access  
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: 14)
Journal of Medical Microbiology     Full-text available via subscription   (Followers: 3)
Journal of Microbiological Methods     Hybrid Journal   (Followers: 2)
Journal of Microbiology     Hybrid Journal   (Followers: 7)
Journal of Microbiology and Antimicrobials     Open Access   (Followers: 2)
Journal of Microbiology Research     Open Access   (Followers: 2)
Journal of Micropalaeontology     Hybrid Journal   (Followers: 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: 12)
Journal of Molecular Pathophysiology     Open Access   (Followers: 1)
Journal of Molecular Psychiatry     Open Access   (Followers: 9)
Journal of Morphology     Hybrid Journal   (Followers: 3)
Journal of Pharmacy & Bioresources     Full-text available via subscription   (Followers: 3)
Journal of Plant Molecular Biology and Biotechnology     Open Access   (Followers: 7)
Journal of Plant Pathology & Microbiology     Open Access  
Journal of Proteome Science and Computational Biology     Open Access  
Journal of Regenerative Medicine and Tissue Engineering     Open Access   (Followers: 3)
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: 1)
Journal of Tropical Microbiology and Biotechnology     Full-text available via subscription  
Jundishapur Journal of Microbiology     Open Access  
Letters In Applied Microbiology     Hybrid Journal   (Followers: 5)
Macrophage     Open Access  
MAP Kinase     Open Access  
Medical Mycology     Open Access   (Followers: 5)
Memórias do Instituto Oswaldo Cruz     Open Access  
Methods in Molecular Biology     Hybrid Journal   (Followers: 24)
Microbes and Health     Open Access   (Followers: 1)
Microbes and Infection     Full-text available via subscription   (Followers: 4)
Microbial Biotechnology     Open Access   (Followers: 7)
Microbial Cell Factories     Open Access   (Followers: 7)
Microbial Drug Resistance     Hybrid Journal   (Followers: 4)
Microbial Ecology     Hybrid Journal   (Followers: 7)
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: 12)
Microbiology (SGM)     Full-text available via subscription   (Followers: 16)
Microbiology and Immunology     Hybrid Journal   (Followers: 10)
Microbiology and Molecular Biology Reviews     Hybrid Journal   (Followers: 22)
Microbiology Australia     Hybrid Journal  
Microbiology Discovery     Open Access  
Microbiology Indonesia     Open Access  
Microbiology Research     Open Access   (Followers: 7)
MicrobiologyOpen     Open Access   (Followers: 2)
Microbiome     Hybrid Journal   (Followers: 5)
Microbiome Science and Medicine     Open Access  
Microorganisms     Open Access   (Followers: 2)
MicroRNA     Hybrid Journal   (Followers: 1)
Molecular and Cellular Therapies     Open Access  
Molecular Biology and Genetic Engineering     Open Access   (Followers: 1)
Molecular Biology Research Communications     Open Access   (Followers: 1)
Molecular Genetics and Metabolism Reports     Open Access   (Followers: 1)
Molecular Genetics, Microbiology and Virology     Hybrid Journal   (Followers: 6)
Molecular Imaging     Open Access  
Molecular Imaging and Biology     Hybrid Journal   (Followers: 2)
Molecular Medicine     Open Access   (Followers: 1)
Molecular Medicine Reports     Full-text available via subscription   (Followers: 6)
Molecular Microbiology     Hybrid Journal   (Followers: 27)
Molecular Oral Microbiology     Partially Free   (Followers: 3)

        1 2     

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  [3040 journals]
  • The response of growth and patulin production of postharvest pathogen
           Penicillium expansum to exogenous potassium phosphite treatment
    • Authors: Tongfei Lai; Ying Wang; Yaya Fan; Yingying Zhou; Ying Bao; Ting Zhou
      Pages: 1 - 10
      Abstract: Publication date: 6 March 2017
      Source:International Journal of Food Microbiology, Volume 244
      Author(s): Tongfei Lai, Ying Wang, Yaya Fan, Yingying Zhou, Ying Bao, Ting Zhou
      In this study, the effects of exogenous potassium phosphite (Phi) on growth and patulin production of postharvest pathogen Penicillium expansum were assessed. The results indicated that P. expansum under 5mmol/L Phi stress presented obvious development retardation, yield reduction of patulin and lower infectivity to apple fruit. Meanwhile, expression analysis of 15 genes related to patulin biosynthesis suggested that Phi mainly affected the early steps of patulin synthetic route at transcriptional level. Furthermore, a global view of proteome and transcriptome alteration of P. expansum spores during 6h of Phi stress was evaluated by iTRAQ (isobaric tags for relative and absolute quantitation) and RNA-seq (RNA sequencing) approaches. A total of 582 differentially expressed proteins (DEPs) and 177 differentially expressed genes (DEGs) were acquired, most of which participated in carbohydrate metabolism, amino acid metabolism, lipid metabolism, genetic information processing and biosynthesis of secondary metabolites. Finally, 39 overlapped candidates were screened out through correlational analysis between iTRAQ and RNA-seq datasets. These findings will afford more precise and directional clues to explore the inhibitory mechanism of Phi on growth and patulin biosynthesis of P. expansum, and be beneficial to develop effective controlling approaches based on Phi.

      PubDate: 2017-01-07T18:44:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.017
      Issue No: Vol. 244 (2017)
  • Lowering histamine formation in a red Ribera del Duero wine (Spain) by
           using an indigenous O. oeni strain as a malolactic starter
    • Authors: Carmen Berbegal; Yaiza Benavent-Gil; Eva Navascués; Almudena Calvo; Clara Albors; Isabel Pardo; Sergi Ferrer
      Pages: 11 - 18
      Abstract: Publication date: 6 March 2017
      Source:International Journal of Food Microbiology, Volume 244
      Author(s): Carmen Berbegal, Yaiza Benavent-Gil, Eva Navascués, Almudena Calvo, Clara Albors, Isabel Pardo, Sergi Ferrer
      This study demonstrates for the first time that a non-commercial selected autochthonous O. oeni strain has been used to conduct malolactic fermentation (MLF) while lowering histamine formation in the same winery. Lactic acid bacteria (LAB) were isolated from 13 vats before and after spontaneous MLF at the Pago de Carraovejas winery from the Ribera del Duero region (Spain). Only O. oeni were present, typed and characterized, and both histamine producer and non-producers existed. From the non-producers, one strain was selected to become a starter according to its genetic profile, prevalence in the different wines in the winery, resistance to alcoholic degree, resistance to high polyphenolic content, inability to synthesise histamine, growth kinetics and malolactic activity. This starter was produced at semi-industrial levels to inoculate 20,000L of Tempranillo red wine. The inoculated vat showed 5-fold less histamine than the non-inoculated control vat. After 1year, the barrel-ageing histamine concentrations were 3-fold lower in the inoculated vat than in the non-inoculated vat.

      PubDate: 2017-01-07T18:44:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.013
      Issue No: Vol. 244 (2017)
  • Endolysin LysSA97 is synergistic with carvacrol in controlling
           Staphylococcus aureus in foods
    • Authors: Yoonjee Chang; Hyunjin Yoon; Dong-Hyun Kang; Pahn-Shick Chang; Sangryeol Ryu
      Pages: 19 - 26
      Abstract: Publication date: 6 March 2017
      Source:International Journal of Food Microbiology, Volume 244
      Author(s): Yoonjee Chang, Hyunjin Yoon, Dong-Hyun Kang, Pahn-Shick Chang, Sangryeol Ryu
      LysSA97 is an endolysin encoded by the bacteriophage SA97, the genome sequence of which has been recently revealed. LysSA97 has lytic activity against a variety of Staphylococcus strains that cause foodborne illness. In order to improve its potential as a biocontrol agent against Staphylococcus, various types of essential oil-derived active compounds were tested in combination with LysSA97; carvacrol exhibited significant synergistic effects when combined with LysSA97. The synergistic antimicrobial activity between endolysin and carvacrol in food products, including milk and beef, were investigated. While LysSA97 (376nM) and carvacrol (3.33mM) showed 0.8±0.2 and 1.0±0.0logCFU/mL reduction in Staphylococcus aureus cells, respectively; when applied alone in bacterial culture, the cocktail containing both at the same concentrations exhibited a bacterial decrease of 4.5±0.2logCFU/mL. The synergistic activity of carvacrol was also reproduced in combination with other endolysins, and their cooperative bactericidal effects were validated in ten additional S. aureus strains, including two methicillin-resistant S. aureus (MRSA), suggesting the wide application of carvacrol as a bactericidal agent coupled with endolysin. When LysSA97 and carvacrol were used in combination in foods, the synergistic activity appeared to be influenced by the total lipid content of foods, and bacteria in skim milk were more drastically inactivated than those in whole milk. Therefore, this is the first report demonstrating that endolysin and carvacrol act synergistically to inactivate S. aureus in food products.

      PubDate: 2017-01-07T18:44:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.007
      Issue No: Vol. 244 (2017)
  • Source tracking of prokaryotic communities in fermented grain of Chinese
           strong-flavor liquor
    • Authors: Xueshan Wang; Hai Du; Yan Xu
      Pages: 27 - 35
      Abstract: Publication date: 6 March 2017
      Source:International Journal of Food Microbiology, Volume 244
      Author(s): Xueshan Wang, Hai Du, Yan Xu
      The fermentation process of Chinese strong-flavor liquor involves numerous microbes originating from Daqu and pit mud. Daqu is the starter of fermentation, and pit mud acts as another source of inoculum of microbes in the liquor-making process. However, the contribution of microbes in pit mud and Daqu to fermented grain, and the sources of microbes in fermented grain are still waiting to be defined clearly. In this study, prokaryotic communities in fermented grain, pit mud and Daqu were identified via next generation sequencing of the V4 region of 16S rRNA gene. Principal-coordinate analysis indicated that Daqu had stronger influence on the prokaryotic communities in fermented grain at the prophase of fermentation, but pit mud influenced the fermented grain continuously during the whole fermentation process. Totally, 299 genera were detected in all fermented grain, pit mud and Daqu samples. Among them, 204 genera were detected in 3days' fermented grain. Ten genera (Lactobacillus, Leuconostoc, Staphylococcus, Gluconobacter, Acetobacter, Petrimonas, Clostridium, Ruminococcus, Methanobacterium and Methanobrevibacter) were dominant, and accounted for 84.31%–87.13% relative abundance of the total prokaryotic community in fermented grain. Venn analysis indicated Daqu was the main source of strict aerobes and facultative aerobes, which took up over 74% of prokaryotic communities in fermented grain. Conversely, pit mud was the sustained-release source of anaerobes, which accounted for over 14% of prokaryotic communities in fermented grain. In addition, part of anaerobes originated from both Daqu and pit mud. This study could help track the source of prokaryotic communities in fermented grain, and improve the quality and controllability in liquor production.

      PubDate: 2017-01-07T18:44:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.018
      Issue No: Vol. 244 (2017)
  • Characterization of Fusarium graminearum isolates recovered from wheat
           samples from Argentina by Fourier transform infrared spectroscopy:
           Phenotypic diversity and detection of specific markers of aggressiveness
    • Authors: Cecilia B. Fígoli; Rodrigo Rojo; Laura A. Gasoni; Gisele Kikot; Mariana Leguizamón; Raúl R. Gamba; Alejandra Bosch; Teresa M. Alconada
      Pages: 36 - 42
      Abstract: Publication date: 6 March 2017
      Source:International Journal of Food Microbiology, Volume 244
      Author(s): Cecilia B. Fígoli, Rodrigo Rojo, Laura A. Gasoni, Gisele Kikot, Mariana Leguizamón, Raúl R. Gamba, Alejandra Bosch, Teresa M. Alconada
      Fusarium graminearum is the primary causal agent of Fusarium head blight of wheat in Argentina. This disease affects crop yields and grain quality also reducing the wheat end-use, and causing mycotoxin contamination. The aim of this work was to analyze the phenotypic characteristics associated with phenotypic diversity and aggressiveness of 34 F. graminearum sensu stricto isolates recovered from Argentinean fields in the 2008 growing season using the Fourier Transform Infrared (FTIR) dried film technology. We applied this technique also to search for spectral specific markers associated with aggressiveness. The combination of FTIR technology with hierarchical cluster analysis allowed us to determine that this population constitutes a highly diverse and heterogeneous group of fungi with significant phenotypic variance. Still, when the spectral features of a set of these isolates were compared against their aggressiveness, as measured by disease severity, thousand grains weight, and relative yield reduction, we found that the more aggressive isolates were richer in lipid content. Therefore, we could define several spectroscopic markers (>CH stretching modes in the 3000–2800 window, >CO and CO vibrational modes of esters at 1765–1707cm−1 and 1474–900cm−1, respectively), mostly assigned to lipid content that could be associated with F. graminearum aggressiveness. All together, by the application of FTIR techniques and simple multivariate analyses, it was possible to gain significant insights into the phenotypic characterization of F. graminearum local isolates, and to establish the existence of a direct relationship between lipid content and fungal aggressiveness. Considering that lipids have a major role as mediators in the interaction between plants and fungi our results could represent an attractive outcome in the study of Fusarium pathogenesis.

      PubDate: 2017-01-07T18:44:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.016
      Issue No: Vol. 244 (2017)
  • Quantitative assessment of viable cells of Lactobacillus plantarum strains
           in single, dual and multi-strain biofilms
    • Authors: Mónica D. Fernández Ramírez; Ioannis Kostopoulos; Eddy J. Smid; Masja N. Nierop Groot; Tjakko Abee
      Pages: 43 - 51
      Abstract: Publication date: 6 March 2017
      Source:International Journal of Food Microbiology, Volume 244
      Author(s): Mónica D. Fernández Ramírez, Ioannis Kostopoulos, Eddy J. Smid, Masja N. Nierop Groot, Tjakko Abee
      Biofilms of Lactobacillus plantarum are a potential source for contamination and recontamination of food products. Although biofilms have been mostly studied using single species or even single strains, it is conceivable that in a range of environmental settings including food processing areas, biofilms are composed of multiple species with each species represented by multiple strains. In this study six spoilage related L. plantarum strains FBR1-FBR6 and the model strain L. plantarum WCFS1 were characterised in single, dual and multiple strain competition models. A quantitative PCR approach was used with added propidium monoazide (PMA) enabling quantification of intact cells in the biofilm, representing the viable cell fraction that determines the food spoilage risk. Our results show that the performance of individual strains in multi-strain cultures generally correlates with their performance in pure culture, and relative strain abundance in multi-strain biofilms positively correlated with the relative strain abundance in suspended (planktonic) cultures. Performance of individual strains in dual-strain biofilms was highly influenced by the presence of the secondary strain, and in most cases no correlation between the relative contributions of viable planktonic cells and viable cells in the biofilm was noted. The total biofilm quantified by CV staining of the dual and multi-strain biofilms formed was mainly correlated to CV values of the dominant strain obtained in single strain studies. However, the combination of strain FBR5 and strain WCFS1 showed significantly higher CV values compared to the individual performances of both strains indicating that total biofilm formation was higher in this specific condition. Notably, L. plantarum FBR5 was able to outgrow all other strains and showed the highest relative abundance in dual and multi-strain biofilms. All the dual and multi-strain biofilms contained a considerable number of viable cells, representing a potential source of contamination.

      PubDate: 2017-01-07T18:44:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.014
      Issue No: Vol. 244 (2017)
  • Evaluation of Muscodor cinnamomi as an egg biofumigant for the reduction
           of microorganisms on eggshell surfaces and its effect on egg quality
    • Authors: Nakarin Suwannarach; Chariya Kaewyana; Arpaporn Yodmeeklin; Jaturong Kumla; Kenji Matsui; Saisamorn Lumyong
      Pages: 52 - 61
      Abstract: Publication date: 6 March 2017
      Source:International Journal of Food Microbiology, Volume 244
      Author(s): Nakarin Suwannarach, Chariya Kaewyana, Arpaporn Yodmeeklin, Jaturong Kumla, Kenji Matsui, Saisamorn Lumyong
      The presence of microorganisms on the eggshell surface is a factor of consideration in determining egg quality. These microorganisms can contribute to egg spoilage and can infect the egg. In this study, 18 morphotypes of microorganisms were isolated from eggshells. Morphological, biochemical, physiological and molecular analyses were used to identify these morphotypes into 7 species; Bacillus drentensis, Staphylococcus arlettae, Stap. cohnii, Stap. kloosii, Stap. saprophyticus, Stap. sciuri and Stap. xylosus. The potential of Muscodor cinnamomi to reduce the presence of microorganisms on eggshells by biological fumigation was investigated. The result showed that 16 strains of the tested microorganisms were inactivated after the exposure of the fungal volatile organic compounds. The most abundant compound was 2-methylpropanoic acid, followed by 3-methylbutan-1-ol. Our results indicated that a 24-h period of fumigation of 100g rye grain culture of M. cinnamomi was the minimum dose that could significantly reduce the number of microorganisms on the eggshell surface. Fumigated eggs from both box and cabinet fumigation trials showed significantly lower microbial numbers on the eggshell than non-fumigated eggs during the storage period of 14days. It was found that the values of the yolk index, albumen index and the Haugh unit of the eggs decreased during this storage time. However, those values of the fumigated eggs from both fumigation trials were found to be significantly higher than the non-fumigated eggs after the 24-h fumigation period and following storage for 5, 7 and 14days. However, the values of the albumen index were not found to have significantly increased over 5days of the box trial. This study is the first to report on mycofumigation activity for the purposes of reducing the presence of microorganisms on the surface of eggshells.

      PubDate: 2017-01-07T18:44:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.021
      Issue No: Vol. 244 (2017)
  • Impact of dry chilling on the genetic diversity of Escherichia coli on
           beef carcasses and on the survival of E. coli and E. coli O157
    • Authors: Jeyachchandran Visvalingam; Yang Liu; Xianqin Yang
      Pages: 62 - 66
      Abstract: Publication date: 6 March 2017
      Source:International Journal of Food Microbiology, Volume 244
      Author(s): Jeyachchandran Visvalingam, Yang Liu, Xianqin Yang
      The objective of this study was to examine the effect of dry chilling on the genetic diversity of naturally occurring Escherichia coli on beef carcasses, and to examine whether two populations of E. coli recovered from carcasses during chilling and E. coli O157 differed in their response to desiccation. Isolates of E. coli were obtained from beef carcasses during a 67h dry chilling process and were genotyped using multiple-locus variable-number tandem-repeat analysis (MLVA). Ten E. coli genotypes found only at 0h (group A) and found more than once (group B), as well as five strains of E. coli O157 (group C) were inoculated on stainless steel coupons and their survival was examined after exposure to 75 and 100% relative humidity (RH) at 0 or 35°C for 67h. A total of 450 E. coli isolates were obtained, with 254, 49, 49, 51, 23, 20, and 4 from 0, 1, 2, 4, 6, 8 and 24h of chilling, respectively. No E. coli were recovered at 67h. MLVA of the isolates revealed 173 distinct genotypes. Genetic diversity of E. coli isolates, defined as ratio of the number of isolates to the number of genotypes, remained between 2.3 and 1.3 during the 24h of chilling. All strains inoculated on stainless steel coupons and exposed to 75% RH at 35°C were completely inactivated, irrespective of their groups. Inactivation of E. coli of the three groups was not significantly (P >0.05) different by exposure to 75% RH at 0°C. The findings indicate that the genetic diversity of E. coli on beef carcasses was not affected by dry chilling. In addition, inactivation of E. coli genotypes and E. coli O157 by desiccation on stainless steel simulating dry chilling conditions did not differ significantly (P >0.05). Thus, dry chilling may be used as an effective antimicrobial intervention for beef carcasses.

      PubDate: 2017-01-07T18:44:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.022
      Issue No: Vol. 244 (2017)
  • Population analysis of biofilm yeasts during fino sherry wine aging in the
           Montilla-Moriles D.O. region
    • Authors: Miriam Marin-Menguiano; Sandra Romero-Sanchez; Ramón R. Barrales; Jose I. Ibeas
      Pages: 67 - 73
      Abstract: Publication date: 6 March 2017
      Source:International Journal of Food Microbiology, Volume 244
      Author(s): Miriam Marin-Menguiano, Sandra Romero-Sanchez, Ramón R. Barrales, Jose I. Ibeas
      Fino is the most popular sherry wine produced in southern Spain. Fino is matured by biological aging under a yeast biofilm constituted of Saccharomyces cerevisiae yeasts. Although different S. cerevisiae strains can be identified in such biofilms, their diversity and contribution to wine character have been poorly studied. In this work, we analyse the flor yeast population in five different wineries from the Montilla-Moriles D.O. (Denominación de Origen) in southern Spain. Yeasts present in wines of different ages were identified using two different culture-dependent molecular techniques. From 2000 individual yeast isolates, five different strains were identified with one of them dominating in four out of the five wineries analysed, and representing 76% of all the yeast isolates collected. Surprisingly, this strain is similar to the predominant strain isolated twenty years ago in Jerez D.O. wines, suggesting that this yeast is particularly able to adapt to such a stressful environment. Fino wine produced with pure cultures of three of the isolated strains resulted in different levels of acetaldehyde. Because acetaldehyde levels are a distinctive characteristic of fino wines and an indicator of fino aging, the use of molecular techniques for yeast identification and management of yeast populations may be of interest for fino wine producers looking to control one of the main features of this wine.

      PubDate: 2017-01-07T18:44:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.019
      Issue No: Vol. 244 (2017)
  • Impact of environmental factors on the culturability and viability of
           Listeria monocytogenes under conditions encountered in food processing
    • Authors: Anaïs Overney; Joséphine Jacques-André-Coquin; Patricia Ng; Brigitte Carpentier; Laurent Guillier; Olivier Firmesse
      Pages: 74 - 81
      Abstract: Publication date: 6 March 2017
      Source:International Journal of Food Microbiology, Volume 244
      Author(s): Anaïs Overney, Joséphine Jacques-André-Coquin, Patricia Ng, Brigitte Carpentier, Laurent Guillier, Olivier Firmesse
      The ability of Listeria monocytogenes to adhere to and persist on surfaces for months or even years may be responsible for its transmission from contaminated surfaces to food products. Hence the necessity to find effective means to prevent the establishment of L. monocytogenes in food processing environments. The aim of this study was to assess, through a fractional experimental design, the environmental factors that could affect the survival of L. monocytogenes cells on surfaces to thereby prevent the persistence of this pathogen in conditions mimicking those encountered in food processing plants: culture with smoked salmon juice or meat exudate, use of two materials with different hygiene status, biofilm of L. monocytogenes in pure-culture or dual-culture with a Pseudomonas fluorescens strain, application of a drying step after cleaning and disinfection (C&D) and comparison of two strains of L. monocytogenes. Bacterial survival was assessed by culture, qPCR to quantify total cells, and propidium monoazide coupled with qPCR to quantify viable cells and highlight viable but non-culturable (VBNC) cells. Our results showed that failure to apply C&D causes cell persistence on surfaces. Moreover, the sanitation procedure leads only to a loss of culturability and appearance of VBNC populations. However, an additional daily drying step after C&D optimises the effectiveness of these procedures to reduce culturable populations. Our results reinforce the importance to use molecular tools to monitor viable pathogens in food processing plants to avoid underestimating the amounts of cells using only methods based on cell culture.

      PubDate: 2017-01-07T18:44:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.012
      Issue No: Vol. 244 (2017)
  • Antibacterial effect of 405±5nm light emitting diode illumination against
           Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella on the
           surface of fresh-cut mango and its influence on fruit quality
    • Authors: Min-Jeong Kim; Chee Hwa Tang; Woo Suk Bang; Hyun-Gyun Yuk
      Pages: 82 - 89
      Abstract: Publication date: 6 March 2017
      Source:International Journal of Food Microbiology, Volume 244
      Author(s): Min-Jeong Kim, Chee Hwa Tang, Woo Suk Bang, Hyun-Gyun Yuk
      To investigate a potential of 405±5nm light emitting diode (LED) as a novel technology for food preservation, the antibacterial effect of 405±5nm LED on Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella spp. on the surface of fresh-cut mango and its influence on fruit quality were evaluated at different storage temperatures. LED-illumination inactivated 1.0–1.6 logCFU/cm2 of populations at 4 and 10°C for 36–48h (total dose, 2.6–3.5kJ/cm2) regardless of bacterial species, while those on non-illuminated mange remained unchanged or slightly increased during storage. At 20°C for 24h (total dose, 1.7kJ/cm2), non-illuminated E. coli O157:H7 and Salmonella gradually grew, whereas LED-illumination reduced 1.2 log of Salmonella and inhibited the growth of E. coli O157:H7. Unlike these, non-illuminated L. monocytogenes cells rapidly increased to 7.3 log, while illuminated cells reached 4.6 log, revealing that LED-illumination delayed their growth. There were no significant (P >0.05) differences in color, antioxidant capacity, ascorbic acid, β-carotene, and flavonoid between non-illuminated and illuminated cut mangoes, regardless of storage temperature. These results suggest that 405±5nm LEDs in combination with chilling temperatures could be applied to preserve fresh-cut fruits without deterioration of physicochemical quality of fruits at food establishments, minimizing the risk of foodborne disease.

      PubDate: 2017-01-07T18:44:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.023
      Issue No: Vol. 244 (2017)
  • Vibrio parahaemolyticus O4:K8 forms a potential predominant clone in
           southern China as detected by whole-genome sequence analysis
    • Authors: Baisheng Li; Xingfen Yang; Hailing Tan; Bixia Ke; Dongmei He; Changwen Ke; Yonghui Zhang
      Pages: 90 - 95
      Abstract: Publication date: 6 March 2017
      Source:International Journal of Food Microbiology, Volume 244
      Author(s): Baisheng Li, Xingfen Yang, Hailing Tan, Bixia Ke, Dongmei He, Changwen Ke, Yonghui Zhang
      Vibrio parahaemolyticus has been the most common food-borne pathogen in southern China, especially the O3:K6 pandemic clone and its serovariants. Recently, the serotype O4:K8 became more and more prevalent in southern China, which was different from the O3:K6 pandemic clone. Thus, the aim of the present work was to elucidate the molecular characteristics of the O4:K8. Some O3:K6 pandemic clone and its serovariants isolated in the same period were selected for comparative analysis, which were still dominant clone locally. The whole genome sequencing (WGS) was applied to characterize 20 strains of V. parahaemolyticus isolated from food-borne diarrheal cases and belonging to the serotype O4:K8, O3:K6 and O1:KUT (untypable), prevalent serotypes in recent southern China. The results showed that all these isolates were positive for the thermostable direct hemolysin gene (tdh), while negative for the TDH-related hemolysin gene (trh). We compared the V. parahaemolyticus strains to those of 31 strains isolated overseas and were available from NCBI genome database. A WGS-SNPs phylogenetic analysis of all the genomes revealed that the strains formed an important genetic lineage, which was genetically distinct from the O3:K6, O1:KUT and other internationals strains. Comparative genome analysis also revealed that all the O4:K8 strains carried the entire T3SS-1 and VpaI-7 (T3SS-2) regions, the most important virulent elements of the O3:K6 pandemic clone. However, all the O4:K8 strains lacked the entire VpaI-1 and VpaI-4 regions and carried only few ORFs of the VpaI-5 and VpaI-6, which were considered to be unique among post-1995 strains belonging to the O3:K6 pandemic clone. Our data showed that the O4:K8 strains possessed the virulence factors similar to the O3:K6 pandemic clone, which may have enabled them to become prevalent in southern China. Our study also revealed that WGS-bases analysis may help improve understanding epidemiology of this bacterium in food-borne disease surveillance.

      PubDate: 2017-01-07T18:44:20Z
      DOI: 10.1016/j.ijfoodmicro.2017.01.001
      Issue No: Vol. 244 (2017)
  • Sulfur dioxide addition at crush alters Saccharomyces cerevisiae strain
           composition in spontaneous fermentations at two Canadian wineries
    • Authors: Sydney C. Morgan; Chrystal M. Scholl; Natasha L. Benson; Morgan L. Stone; Daniel M. Durall
      Pages: 96 - 102
      Abstract: Publication date: 6 March 2017
      Source:International Journal of Food Microbiology, Volume 244
      Author(s): Sydney C. Morgan, Chrystal M. Scholl, Natasha L. Benson, Morgan L. Stone, Daniel M. Durall
      During winemaking, sulfur dioxide (SO2) is often added prior to the onset of alcoholic fermentation to prevent the growth of spoilage microorganisms and to create an environment that promotes the rapid colonization of the grape must by Saccharomyces cerevisiae. Most recent research has focused on the impacts of SO2 additions on spoilage microorganisms or on the yeast community at a species level, but less is known about the impacts that SO2 additions have on S. cerevisiae populations. We investigated whether different levels of SO2 addition at crush (0, 20, or 40mg/L SO2) have an effect upon the relative abundance and composition of S. cerevisiae strains conducting spontaneous fermentations of two grape varietals at two commercial wineries. Yeast isolates collected from fermentations were identified to the strain level using microsatellite analysis. Commercial strains made up the majority (64–98%) of the S. cerevisiae strains isolated during fermentation, and most of these commercial strains were used as inoculants by their respective wineries. Different SO2 additions were found to significantly alter S. cerevisiae strain compositions at both wineries (p ≤0.002). The results of this study demonstrate that initial SO2 addition significantly alters the S. cerevisiae strain composition in spontaneous fermentations, and highlights the dominance of commercial strains in commercial winery environments. Because different yeast strains are known to produce different chemical and sensory profiles, our findings have important implications for winemakers. In addition, adding different concentrations of SO2 may be a way for winemakers to manage or control the strain composition during spontaneous fermentations.

      PubDate: 2017-01-15T18:57:17Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.025
      Issue No: Vol. 244 (2017)
  • PCR screening of an African fermented pearl-millet porridge metagenome to
           investigate the nutritional potential of its microbiota
    • Authors: Fabien Saubade; Christèle Humblot; Youna M. Hemery; Jean-Pierre Guyot
      Pages: 103 - 110
      Abstract: Publication date: 6 March 2017
      Source:International Journal of Food Microbiology, Volume 244
      Author(s): Fabien Saubade, Christèle Humblot, Youna M. Hemery, Jean-Pierre Guyot
      Cereals are staple foods in most African countries, and many African cereal-based foods are spontaneously fermented. The nutritional quality of cereal products can be enhanced through fermentation, and traditional cereal-based fermented foods (CBFFs) are possible sources of lactic acid bacteria (LAB) with useful nutritional properties. The nutritional properties of LAB vary depending on the species and even on the strain, and the microbial composition of traditional CBFFs varies from one traditional production unit (TPU) to another. The nutritional quality of traditional CBFFs may thus vary depending on their microbial composition. As the isolation of potentially useful LAB from traditional CBFFs can be very time consuming, the aim of this study was to use PCR to assess the nutritional potential of LAB directly on the metagenomes of pearl-millet based fermented porridges (ben-saalga) from Burkina Faso. Genes encoding enzymes involved in different nutritional activities were screened in 50 metagenomes extracted from samples collected in 10 TPUs in Ouagadougou. The variability of the genetic potential was recorded. Certain genes were never detected in the metagenomes (genes involved in carotenoid synthesis) while others were frequently detected (genes involved in folate and riboflavin production, starch hydrolysis, polyphenol degradation). Highly variable microbial composition - assessed by real-time PCR - was observed among samples collected in different TPUs, but also among samples from the same TPU. The high frequency of the presence of genes did not necessarily correlate with in situ measurements of the expected products. Indeed, no significant correlation was found between the microbial variability and the variability of the genetic potential. In spite of the high rate of detection (80%) of both genes folP and folK, encoding enzymes involved in folate synthesis, the folate content in ben-saalga was rather low (median: 0.5μg/100g fresh weight basis). This work highlighted the limit of evaluating the nutritional potential of the microbiota of traditional fermented foods by the only screening of genes in metagenomes, and suggests that such a screening should be completed by a functional analysis.

      PubDate: 2017-01-15T18:57:17Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.020
      Issue No: Vol. 244 (2017)
  • Efficacy of vacuum steam pasteurization for inactivation of Salmonella PT
           30, Escherichia coli O157:H7 and Enterococcus faecium on low moisture
    • Authors: Manoj K. Shah; Gladys Asa; Julie Sherwood; Kari Graber; Teresa M. Bergholz
      Pages: 111 - 118
      Abstract: Publication date: 6 March 2017
      Source:International Journal of Food Microbiology, Volume 244
      Author(s): Manoj K. Shah, Gladys Asa, Julie Sherwood, Kari Graber, Teresa M. Bergholz
      Low moisture foods such as nuts, spices, and seeds have been implicated in several outbreaks due to Salmonella or E. coli O157:H7 contamination. Such foods may be consumed raw, and can be used as ingredients in other food products. While numerous thermal inactivation studies have been conducted for Salmonella on nuts, studies on other seeds and grains are minimal. Product water activity can influence the thermal resistance of pathogens, where thermal resistance increases as water activity decreases, leading to a requirement for higher temperatures and longer exposure times to achieve significant reduction of pathogen numbers. Vacuum steam pasteurization uses steam under vacuum, which can be operated at temperatures above and below 100°C. The objective of this study was to determine the efficacy of vacuum steam pasteurization for inactivation of pathogens on whole flaxseed, quinoa, sunflower kernels, milled flaxseed and whole black peppercorns. The use of E. faecium as a potential surrogate for Salmonella and E. coli O157:H7 in vacuum steam pasteurization was also evaluated. Pasteurization for 1min at 75°C yielded average log reductions of 5.48±1.22, 5.71±0.40 and 5.23±0.61 on flaxseed, 4.29±0.92, 5.89±0.26 and 2.39±0.83 on quinoa, and 4.01±0.74, 5.40±0.83 and 2.99±0.92 on sunflower kernels for Salmonella PT 30, E. coli O157:H7 and E. faecium, respectively. Similarly, on milled flaxseed and black peppercorns average log reductions of 3.02±0.79 and 6.10±0.64CFU/g were observed for Salmonella PT 30 after 1min of treatment at 75°C but, on average, >6.0 log reductions were observed after pasteurization at 85°C. Our data demonstrate that vacuum steam pasteurization can be effectively used to reduce pathogens on these low moisture foods at temperature as low as 75 and 85°C, and that E. faecium may be used as a potential surrogate for Salmonella PT 30 and E. coli O157:H7.

      PubDate: 2017-01-15T18:57:17Z
      DOI: 10.1016/j.ijfoodmicro.2017.01.003
      Issue No: Vol. 244 (2017)
  • ICFMH Announcement
    • Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242

      PubDate: 2017-01-07T18:44:20Z
  • Comparative sequence analysis of enteroaggregative Escherichia coli
           heat-stable enterotoxin 1 identified in Korean and Japanese Escherichia
           coli strains
    • Authors: Dong Joo Seo; SunKeum Choi; Su Been Jeon; Suntak Jeong; Hyunkyung Park; Bog-Hieu Lee; Geun-Bae Kim; Soo-Jin Yang; Yoshikazu Nishikawa; Changsun Choi
      Pages: 1 - 8
      Abstract: Publication date: 21 February 2017
      Source:International Journal of Food Microbiology, Volume 243
      Author(s): Dong Joo Seo, SunKeum Choi, Su Been Jeon, Suntak Jeong, Hyunkyung Park, Bog-Hieu Lee, Geun-Bae Kim, Soo-Jin Yang, Yoshikazu Nishikawa, Changsun Choi
      The aim of this study was to compare the sequence of the astA gene found in 8 Korean and 11 Japanese Escherichia coli isolates. Conventional PCR was used to amplify the astA gene from the chromosomal and plasmid DNA preparation samples of each isolate using commercial DNA extraction kits. Cloning of the PCR products, sequence analysis, and pulse field gel electrophoresis (PFGE) were sequentially performed. An identical copy of astA in each isolate were found for 8 Korean and 8 Japanese E. coli strains isolated from bovine, porcine, and healthy human carriers. Among these, 1 Korean and 4 Japanese isolates carried a stop mutation at residue 16. Three Japanese outbreak strains (V199, V638, and 96-127-23) carried multiple clones of astA gene with multiple amino acids changes at residues 11, 16, 20, 23, 30, 33, and 34. Compared with the non-diarrheal isolates, clonal diversity and sequence variations of the astA gene in outbreak isolates may be associated with virulence potential of EAST1.

      PubDate: 2016-12-08T04:23:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.017
      Issue No: Vol. 243 (2016)
  • A proteomic approach for rapid identification of Weissella species
           isolated from Korean fermented foods on MALDI-TOF MS supplemented with an
           in-house database
    • Authors: Eiseul Kim; Youngjae Cho; Yoonju Lee; Sun-Kyung Han; Chang-Gyeom Kim; Dong-Won Choo; Young-Rok Kim; Hae-Yeong Kim
      Pages: 9 - 15
      Abstract: Publication date: 21 February 2017
      Source:International Journal of Food Microbiology, Volume 243
      Author(s): Eiseul Kim, Youngjae Cho, Yoonju Lee, Sun-Kyung Han, Chang-Gyeom Kim, Dong-Won Choo, Young-Rok Kim, Hae-Yeong Kim
      Weissella are obligate heterofermentative lactic acid bacteria belonging to the Leuconostocaceae family. Some Weissella can be found in salted and fermented foods, such as kimchi and jeotgal, and plays an important role in the fermentation process. In the present study, for the first time, a rapid and accurate identification method for Weissella species from kimchi and jeotgal was developed based on MALDI-TOF MS, supplemented with an in-house database. Of the 135 Weissella spectra aligned with the MALDI bioTyper database, 56 isolates (41.5%) yielded no reliable identification results with low log scores (<1.7). After registering the spectra of six Weissella reference strains, all of the isolates were correctly identified, of which 113 (83.7%) and 22 (16.3%) were identified at the species and genus level, respectively. Moreover, a dendrogram generated by protein profiles of the different Weissella species clearly presented distinctive clusters, and PCA analysis separated the spectra of Weissella species into four clusters. In comparing food origins, different Weissella species were identified from two fermented foods. W. soli and W. cibaria were isolated from kimchi, while W. thailandensis and W. halotolerans were isolated from jeotgal. The results of our proteomic approach confirm that the MALDI bioTyper database, with our in-house Weissella database, is sufficient for Weissella identification. The MALDI-TOF MS method provides fast and reliable discrimination between different species in the genus Weissella and, therefore, will be useful for safety control in fish farms or in the production of fermented foods. This method can also be applied to the control of opportunistic pathogenic Weissella in human clinical infections.

      PubDate: 2016-12-08T04:23:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.027
      Issue No: Vol. 243 (2016)
  • Linking wine lactic acid bacteria diversity with wine aroma and flavour
    • Authors: Maria Stella Cappello; Giacomo Zapparoli; Antonio Logrieco; Eveline J Bartowsky
      Pages: 16 - 27
      Abstract: Publication date: 21 February 2017
      Source:International Journal of Food Microbiology, Volume 243
      Author(s): Maria Stella Cappello, Giacomo Zapparoli, Antonio Logrieco, Eveline J Bartowsky
      In the last two decades knowledge on lactic acid bacteria (LAB) associated with wine has increased considerably. Investigations on genetic and biochemistry of species involved in malolactic fermentation, such as Oenococcus oeni and of Lactobacillus have enabled a better understand of their role in aroma modification and microbial stability of wine. In particular, the use of molecular techniques has provided evidence on the high diversity at species and strain level, thus improving the knowledge on wine LAB taxonomy and ecology. These tools demonstrated to also be useful to detect strains with potential desirable or undesirable traits for winemaking purposes. At the same time, advances on the enzymatic properties of wine LAB responsible for the development of wine aroma molecules have been undertaken. Interestingly, it has highlighted the high intraspecific variability of enzymatic activities such as glucosidase, esterase, proteases and those related to citrate metabolism within the wine LAB species. This genetic and biochemistry diversity that characterizes wine LAB populations can generate a wide spectrum of wine sensory outcomes. This review examines some of these interesting aspects as a way to elucidate the link between LAB diversity with wine aroma and flavour. In particular, the correlation between inter- and intra-species diversity and bacterial metabolic traits that affect the organoleptic properties of wines is highlighted with emphasis on the importance of enzymatic potential of bacteria for the selection of starter cultures to control MLF and to enhance wine aroma.

      PubDate: 2016-12-14T17:10:50Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.025
      Issue No: Vol. 243 (2016)
  • Single vs multiple-spore inoculum effect on growth kinetic parameters and
           modeled probabilities of growth and aflatoxin B1 production of Aspergillus
           flavus on pistachio extract agar
    • Authors: Laila Aldars-García; Vicente Sanchis; Antonio J. Ramos; Sonia Marín
      Pages: 28 - 35
      Abstract: Publication date: 21 February 2017
      Source:International Journal of Food Microbiology, Volume 243
      Author(s): Laila Aldars-García, Vicente Sanchis, Antonio J. Ramos, Sonia Marín
      The objective of the present study was to assess the differences in modeled growth/AFB1 production probability and kinetic growth parameters for Aspergillus flavus inoculated as single spores or in a concentrated inoculation point (~500 spores). The experiment was carried out at 25°C and at two water activities (0.85 and 0.87) on pistachio extract agar (3%). Binary data obtained from growth and AFB1 studies were modeled using linear logistic regression analysis. The radial growth curve for each colony was fitted to a linear model for the estimation of the lag phase for growth and the mycelial growth rate. In general, radial growth rate and lag phase for growth were not normally distributed and both of them were affected by the inoculation type, with the lag phase for growth being more affected. Changing from the multiple spore to the single spore inoculation led to a delay of approximately 3–5days on the lag phase and higher growth rates for the multiple spore experiment were found. The same trend was observed on the probability models, with lower predicted probabilities when colonies came up from single spores, for both growth and AFB1 production probabilities. Comparing both types of models, it was concluded that a clear overestimation of the lag phase for growth occurred using the linear model, but only in the multiple spore experiment. Multiple spore inoculum gave very similar estimated time to reach some set probabilities (t10, t50 and t100) for growth or AFB1 production due to the abruptness of the logistic curve developed. The observed differences suggest that inoculum concentration greatly affects the outcome of the predictive models, the estimated times to growth/AFB1 production being much earlier for the concentrated inoculum than for a single spore colony (up to 9days). Thus the number of spores used to generate data in predictive mycology experiments should be carefully controlled in order to predict as accurately as possible the fungal behavior in a foodstuff.

      PubDate: 2016-12-14T17:10:50Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.026
      Issue No: Vol. 243 (2016)
  • Digital RT-PCR method for hepatitis A virus and norovirus quantification
           in soft berries
    • Authors: Audrey Fraisse; Coralie Coudray-Meunier; Sandra Martin-Latil; Catherine Hennechart-Collette; Sabine Delannoy; Patrick Fach; Sylvie Perelle
      Pages: 36 - 45
      Abstract: Publication date: 21 February 2017
      Source:International Journal of Food Microbiology, Volume 243
      Author(s): Audrey Fraisse, Coralie Coudray-Meunier, Sandra Martin-Latil, Catherine Hennechart-Collette, Sabine Delannoy, Patrick Fach, Sylvie Perelle
      Raw fruits may harbour many pathogens of public health concern including enteric viruses, which are the leading cause of foodborne outbreaks. Recently, consumption of soft berries has been associated with increasing reports of norovirus and hepatitis A virus outbreaks in Europe. Due to their low infectious doses and low concentrations in food samples, an efficient and sensitive analytical method is required for virus detection. In this study we explored two different ways to improve the reference method for the detection of enteric viruses in soft fruits (ISO/TS 15216-1; 15216-2): an additional purification step after RNA extraction; and the detection of enteric viral genome by an absolute quantification method (microfluidic digital RT-PCR). Both of these approaches led to an improvement of enteric virus detection in soft berries by greatly lowering PCR inhibition, raising viral extraction efficiencies and enabling validation of controls using pure RNA extracts. The PCR inhibitor removal step can be easily included in the routine method. Absolute quantification by digital RT-PCR may be a relevant alternative method to standardize quantification of enteric viruses in foodstuffs.

      PubDate: 2016-12-14T17:10:50Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.022
      Issue No: Vol. 243 (2016)
  • The first report of A. novoparasiticus, A. arachidicola and A.
           pseudocaelatus in Brazilian corn kernels
    • Authors: Helena Paula Viaro; Josué José da Silva; Larissa de Souza Ferranti; Jaqueline Gozzi Bordini; Fernanda Pelisson Massi; Maria Helena Pelegrinelli Fungaro
      Pages: 46 - 51
      Abstract: Publication date: 21 February 2017
      Source:International Journal of Food Microbiology, Volume 243
      Author(s): Helena Paula Viaro, Josué José da Silva, Larissa de Souza Ferranti, Jaqueline Gozzi Bordini, Fernanda Pelisson Massi, Maria Helena Pelegrinelli Fungaro
      Maize is one of the most important commercial crops cultivated throughout the world, mostly in tropical and subtropical countries. It is highly susceptible to mycotoxins, toxic secondary metabolites produced by fungi. In this study, we assessed freshly harvested corn produced in Brazil for aflatoxin contamination and the presence of Aspergillus. B type aflatoxins (AFB1 +AFB2) were detected in 56% of 16 grain samples, while G type aflatoxins (AFG1 +AFG2) were detected in 25%. Of the total number of grains (n =1920) evaluated for the presence of fungi species, 4.7% were infected with Aspergillus species, 74.5% and 16.7% respectively with Fusarium and Penicillium species and 4.1% with other fungi genera. In total, 89 Aspergillus isolates were identified, most (86 isolates) characterized as belonging to Aspergillus section Flavi, and the remainder to Aspergillus section Cremei (2 isolates) and Aspergillus section Terrei (1 isolate). All the isolates of section Flavi were subjected to molecular analysis. They were found to belong to six species, including Aspergillus novoparasiticus, Aspergillus arachidicola and Aspergillus pseudocaelatus, all aflatoxins B and G producing species, which are herein described for the first time infecting corn kernels.

      PubDate: 2016-12-14T17:10:50Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.002
      Issue No: Vol. 243 (2016)
  • A minireview on the in vitro and in vivo experiments with anti-Escherichia
           coli O157:H7 phages as potential biocontrol and phage therapy agents
    • Authors: Salehe Sabouri; Zargham Sepehrizadeh; Sahar Amirpour-Rostami; Mikael Skurnik
      Pages: 52 - 57
      Abstract: Publication date: 21 February 2017
      Source:International Journal of Food Microbiology, Volume 243
      Author(s): Salehe Sabouri, Zargham Sepehrizadeh, Sahar Amirpour-Rostami, Mikael Skurnik
      Phage therapy is an old method of combating bacterial pathogens that has recently been taken into consideration due to the alarming spread of antibiotic resistance. Escherichia coli O157:H7 is a foodborne pathogen that causes hemorrhagic colitis and life-threatening Hemolytic Uremic Syndrome (HUS). There are several studies on isolation of specific phages against E. coli O157:H7 and more than 60 specific phages have been published so far. Although in vitro experiments have been successful in elimination or reduction of E. coli O157:H7numbers, in vivo experiments have not been as promising. This may be due to escape of bacteria to locations where phages have difficulties to enter or due to the adverse conditions in the gastrointestinal tract that affect phage viability and proliferation. To get around the latter obstacle, an alternative phage delivery method such as polymer microencapsulation should be tried. While the present time results are not very encouraging the work should be continued as more efficient phage treatment regimens might be found in future.

      PubDate: 2016-12-14T17:10:50Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.004
      Issue No: Vol. 243 (2016)
  • Prevalence and antimicrobial susceptibility of Acinetobacter spp. isolated
           from meat
    • Authors: Ana Carvalheira; Rocio Casquete; Joana Silva; Paula Teixeira
      Pages: 58 - 63
      Abstract: Publication date: 21 February 2017
      Source:International Journal of Food Microbiology, Volume 243
      Author(s): Ana Carvalheira, Rocio Casquete, Joana Silva, Paula Teixeira
      The prevalence and antibiotic resistance of Acinetobacter spp. from fifty samples of meat (chicken, turkey, beef and pork) were evaluated. Acinetobacter spp. was recovered from all samples and the clonal relatedness of 223 isolates identified to belong to the genus Acinetobacter was established by PFGE. A high genetic diversity was observed and 166 isolates from different samples, 141 representing different PFGE profiles, were further identified to the species level by rpoB gene sequencing. Thirteen distinct Acinetobacter species were identified among 156 isolates. The remaining ten isolates may represent three putatively novel species since rpoB sequence homologies with type strains of all available described Acinetobacter species, were <95%. The most common species was Acinetobacter guillouiae with a prevalence of 34.9%. However 18.7% of the strains belong to the Acinetobacter baumannii group (n =31) which include the species Acinetobacter baumannii (n =7), Acinetobacter pittii (n =12), Acinetobacter seifertii (n =8) and Acinetobacter nosocomialis (n =4) that are the species most frequently associated with nosocomial infections worldwide. In general, strains were resistant to some of the antimicrobials most frequently used to treat Acinetobacter infections such as piperacillin-tazobactam (64.9% of strains resistant), ceftazidime (43.5%), ciprofloxacin (42.9%), as well as to colistin (41.7%) and polymyxin B (35.1%), the last-resort drugs to treat infections caused by multidrug-resistant Acinetobacter. The percentage of resistant strains to trimethoprim-sulfamethoxazole, tetracycline, aminoglycosides (amikacin and tobramycin) and ampicillin-sulbactam was >10% (23.2%, 23.2%, 14.3%, 12.5%, 12.5%, respectively). However, resistances to meropenem, imipenem and minocycline were only sporadically observed (8.3%, 1.2% and 1.2%, respectively). Overall, 51.2% of the strains were considered as multidrug-resistant (MDR) and 9.6% as extensively drug-resistant (XDR). The prevalence of MDR strains within the A. baumannii group (38.7%) was lower than the prevalence within the others species identified (54.1%). Therefore, food of animal origin may be a vehicle of spread Acinetobacter strains resistant to several antibiotics in the community and in the hospital setting environment. This may led to nosocomial and community-acquired infections in susceptible individuals.

      PubDate: 2016-12-22T15:57:11Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.001
      Issue No: Vol. 243 (2016)
  • Rapid detection of methicillin-resistant Staphylococcus aureus in pork
           using a nucleic acid-based lateral flow immunoassay
    • Authors: Hongwei Zhang; Luyao Ma; Lina Ma; Marti Z. Hua; Shuo Wang; Xiaonan Lu
      Pages: 64 - 69
      Abstract: Publication date: 21 February 2017
      Source:International Journal of Food Microbiology, Volume 243
      Author(s): Hongwei Zhang, Luyao Ma, Lina Ma, Marti Z. Hua, Shuo Wang, Xiaonan Lu
      Methicillin-resistant Staphylococcus aureus (MRSA) is considered as one of the leading causes of food poisonings worldwide. Due to the high prevalence and extensive challenges in clinical treatment, a rapid and accurate detection method is required to differentiate MRSA from other S. aureus isolated from foods. Since the methicillin resistance of S. aureus is due to the acquisition of the mecA gene from staphylococcal chromosome cassette, the presence of the mecA gene is interpreted as a marker for the identification of MRSA. In this study, a low-cost lateral flow immunoassay (LFI) strip was used to detect the mecA amplicons subsequent to polymerase chain reaction (PCR). The specificity of this PCR-LFI assay was tested between MRSA and methicillin-susceptive S. aureus. Both the test line and control line were shown up on the LFI strip for MRSA, whereas only the control line developed for methicillin-susceptive S. aureus. The detection limit of PCR-LFI assay was 20fg for genomic DNA (100 times more sensitive than gel electrophoresis) and 2×100 CFU per 100g of pork products after enrichment at 37°C for 48h. The total detection time of using LFI was 3min, which was faster than the conventional electrophoresis (~45min). With the performance of PCR-LFI, 7 out of 42 S. aureus isolates were identified to be MRSA from imported pork products, which was consistent to the standardized minimum inhibitory concentration assay. This mecA-based PCR-LFI strip can be used for rapid and accurate detection of MRSA isolated from commercial pork products.

      PubDate: 2016-12-22T15:57:11Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.003
      Issue No: Vol. 243 (2016)
  • Thermal inactivation and sublethal injury kinetics of Salmonella enterica
           and Listeria monocytogenes in broth versus agar surface
    • Authors: Xiang Wang; Frank Devlieghere; Annemie Geeraerd; Mieke Uyttendaele
      Pages: 70 - 77
      Abstract: Publication date: 21 February 2017
      Source:International Journal of Food Microbiology, Volume 243
      Author(s): Xiang Wang, Frank Devlieghere, Annemie Geeraerd, Mieke Uyttendaele
      The objective of the present study was to compare the thermal inactivation and sublethal injury kinetics of Salmonella enterica and Listeria monocytogenes in broth (suspended cells) and on solid surface (agar-seeded cells). A 3-strain cocktail of S. enterica or L. monocytogenes inoculated in broth or on agar was subjected to heating in a water bath at various set temperatures (55.0, 57.5 and 60.0°C for S. enterica and 60.0, 62.5 and 65°C for L. monocytogenes). The occurrence of sublethally injured cells was determined by comparing enumerations on nonselective (TSAYE) and selective (XLD or ALOA) media. Results showed that the inactivation curves obtained from selective media were log-linear, and significant shoulders (p <0.05) were observed on some of the inactivation curves from TSAYE media. The D-values derived from the total population were higher than those from the uninjured cells. Generally, cells on agar surface exhibited higher heat resistance than those in broth. For S. enterica, cell injury increased with the exposure time, no difference was observed when treated at temperatures from 55.0 to 60.0°C, while for L. monocytogenes, cell injury increased significantly with heating time and treatment temperature (from 60.0 to 65°C). Moreover, the degree of sublethal injury affected by thermal treatment in broth or on agar surface depended upon the target microorganism. Higher proportions of injured S. enterica cells were observed for treatment in broth than on agar surface, while the opposite was found for L. monocytogenes. The provided information may be used to assess the efficacy of thermal treatment processes on surfaces for inactivation of S. enterica and L. monocytogenes, and it provides insight into the sublethally injured survival state of S. enterica and L. monocytogenes treated in liquid or on solid food.

      PubDate: 2016-12-22T15:57:11Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.008
      Issue No: Vol. 243 (2016)
  • Ultrasound attenuation of lactobacilli and bifidobacteria: Effect on some
           technological and probiotic properties
    • Authors: Angela Racioppo; Maria Rosaria Corbo; Claudia Piccoli; Milena Sinigaglia; Barbara Speranza; Antonio Bevilacqua
      Pages: 78 - 83
      Abstract: Publication date: 21 February 2017
      Source:International Journal of Food Microbiology, Volume 243
      Author(s): Angela Racioppo, Maria Rosaria Corbo, Claudia Piccoli, Milena Sinigaglia, Barbara Speranza, Antonio Bevilacqua
      Attenuation can be regarded as a tool to modulate the metabolism of probiotic bacteria and, consequently, a strategy to reduce the acidification of the active drinks. Attenuation can be done through chemical and physical approaches and ultrasound (US) is a possibility, previously tested to modulate the metabolism of lactic acid bacteria inoculated in a rice drink, but no data are available on the effect of this treatment of the overall profile of probiotic bacteria. Therefore, the main topic of this paper was to study the effect of US-attenuation on some properties of Lactobacillus reuteri, Lactobacillus plantarum, Bifidobacterium longum, and Bifidobacterium infantis (survival at pH2, and 2.5, and with 0.3% of bile salt added, hydrophobicity, acidification, and growth at different temperatures, pH or in presence of 7% NaCl). A preliminary screening was done by using 3 power levels (40, 60, and 80%) and 3 different treatment times (2, 4, and 6min); immediately after sonication, acidification and viable count were tested. The best combination to avoid post-acidification was the following one: power, 60%; time, 6min; pulse, 2s. The effect of this combination on the overall profile of the test strains (functional and technological properties) was studied. This combination exerted a positive effect on the hydrophobicity and adhesion to Caco-2 cells of L. reuteri, although the growth at pH4 was negatively affected. In the other strains, there a was negative effect on acid and bile resistance.

      PubDate: 2016-12-29T18:29:38Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.011
      Issue No: Vol. 243 (2016)
  • A rapid typing method for Listeria monocytogenes based on high-throughput
           multilocus sequence typing (Hi-MLST)
    • Authors: Hajime Takahashi; Ai Iwakawa; Chihiro Ohshima; Daisuke Kyoui; Shiori Kumano; Takashi Kuda; Bon Kimura
      Pages: 84 - 89
      Abstract: Publication date: 21 February 2017
      Source:International Journal of Food Microbiology, Volume 243
      Author(s): Hajime Takahashi, Ai Iwakawa, Chihiro Ohshima, Daisuke Kyoui, Shiori Kumano, Takashi Kuda, Bon Kimura
      Listeria monocytogenes infects humans via food products, causing listeriosis. Consequently, food companies pay meticulous attention to the risk of contamination of their products by this bacterium. While fragment analysis methods such as pulsed-field gel electrophoresis (PFGE) are used to trace the sources of contamination for this bacterium, some drawbacks have been identified, namely the complexity of the methods and the difficulty of making data comparisons. As an alternative, multilocus sequence typing (MLST) is now seeing widespread use; however, owing to its cost, time, and labor requirements, its diffusion into the food industry has been slow. Thus, in the present study, a High-throughput MLST (Hi-MLST) method, which can rapidly, simply, and cheaply perform MLST analyses using a next-generation sequencer (NGS) that can analyze a large volume of base sequences at once was developed. Firstly, a multiplex PCR method designed to amplify seven genes for use in MLST was developed. The discriminatory potential of the developed method was confirmed in silico, and was verified that it has the same discriminatory potential as conventional methods. Next, MLST analysis using multiplex PCR and NGS was performed for 48 strains of L. monocytogenes. The sequences obtained from this analysis have sufficiently reliable quality for all of the genes from of all the strains. Thus, this method could classify the 48 strains into 39 sequence types (ST) with a Diversity index (DI) of 0.989. In summary, using the Hi-MLST method developed in the present study, which combined multiplex PCR and NGS, cut the costs to 1/6th and the time to 1/20th that of conventional MLST methods.

      PubDate: 2016-12-29T18:29:38Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.009
      Issue No: Vol. 243 (2016)
  • Airborne soil particulates as vehicles for Salmonella contamination of
    • Authors: Govindaraj Dev Kumar; Robert C. Williams; Hamzeh M. Al Qublan; Nammalwar Sriranganathan; Renee R. Boyer; Joseph D. Eifert
      Pages: 90 - 95
      Abstract: Publication date: 21 February 2017
      Source:International Journal of Food Microbiology, Volume 243
      Author(s): Govindaraj Dev Kumar, Robert C. Williams, Hamzeh M. Al Qublan, Nammalwar Sriranganathan, Renee R. Boyer, Joseph D. Eifert
      The presence of dust is ubiquitous in the produce growing environment and its deposition on edible crops could occur. The potential of wind-distributed soil particulate to serve as a vehicle for S. Newport transfer to tomato blossoms and consequently, to fruits, was explored. Blossoms were challenged with previously autoclaved soil containing S. Newport (9.39log CFU/g) by brushing and airborne transfer. One hundred percent of blossoms brushed with S. Newport-contaminated soil tested positive for presence of the pathogen one week after contact (P <0.0001). Compressed air was used to simulate wind currents and direct soil particulates towards blossoms. Airborne soil particulates resulted in contamination of 29% of the blossoms with S. Newport one week after contact. Biophotonic imaging of blossoms post-contact with bioluminescent S. Newport-contaminated airborne soil particulates revealed transfer of the pathogen on petal, stamen and pedicel structures. Both fruits and calyxes that developed from blossoms contaminated with airborne soil particulates were positive for presence of S. Newport in both fruit (66.6%) and calyx (77.7%). Presence of S. Newport in surface-sterilized fruit and calyx tissue tested indicated internalization of the pathogen. These results show that airborne soil particulates could serve as a vehicle for Salmonella. Hence, Salmonella contaminated dust and soil particulate dispersion could contribute to pathogen contamination of fruit, indicating an omnipresent yet relatively unexplored contamination route.

      PubDate: 2016-12-29T18:29:38Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.006
      Issue No: Vol. 243 (2016)
  • Application of a 222-nm krypton-chlorine excilamp to control foodborne
           pathogens on sliced cheese surfaces and characterization of the
           bactericidal mechanisms
    • Authors: Jae-Won Ha; Jae-Ik Lee; Dong-Hyun Kang
      Pages: 96 - 102
      Abstract: Publication date: 21 February 2017
      Source:International Journal of Food Microbiology, Volume 243
      Author(s): Jae-Won Ha, Jae-Ik Lee, Dong-Hyun Kang
      This study was conducted to investigate the basic spectral properties of a 222-nm krypton-chlorine (KrCl) excilamp and its inactivation efficacy against major foodborne pathogens on solid media, as well as on sliced cheese compared to a conventional 254-nm low-pressure mercury (LP Hg) lamp. Selective media and sliced cheese inoculated with Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes were irradiated with a KrCl excilamp and a LP Hg lamp at the same dose. The KrCl excilamp showed full radiant intensity from the outset at a wide range of working temperatures, especially at low temperatures of around 0 to 10°C. Irradiation with 222nm UV-C showed significantly (P <0.05) higher inactivation capacity against all three pathogens than 254-nm radiation on both media and sliced cheese surfaces without generating many sublethally injured cells which potentially could recover. The underlying inactivation mechanisms of 222-nm KrCl excilamp treatment were evaluated by fluorescent staining methods and damage to cellular membranes and intracellular enzyme inactivation were the primary factors contributing to the enhanced bactericidal effect. The results of this study suggest that a 222-nm UV-C surface disinfecting system can be applied as an alternative to conventional LP Hg lamp treatment by the dairy industry.

      PubDate: 2016-12-29T18:29:38Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.005
      Issue No: Vol. 243 (2016)
  • High hydrostatic pressure inactivation of murine norovirus and human
           noroviruses on green onions and in salsa
    • Authors: Robert F. Sido; Runze Huang; Chuhan Liu; Haiqiang Chen
      Pages: 1 - 6
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): Robert F. Sido, Runze Huang, Chuhan Liu, Haiqiang Chen
      In this study, high hydrostatic pressure (HHP) was evaluated as an intervention for human noroviruses (HuNoVs) in green onions and salsa. To determine the effect of water during HHP treatment on virus inactivation, a HuNoV surrogate, murine norovirus 1 (MNV-1), was inoculated onto green onions and then HHP-treated at 350MPa with or without water at 4 or 20°C. The presence of water enhanced HHP inactivation of MNV-1 on green onions at 4°C but not at 20°C. To test the temperature effect on HHP inactivation of MNV-1, inoculated green onions were HHP-treated at 300MPa at 1, 4 and 10°C. As the temperature decreased, MNV-1 became more sensitive to HHP treatment. HHP inactivation curves of MNV-1 on green onions and salsa were obtained at 300 or 350MPa for 0.5–3min at 1°C. All three inactivation curves showed a linear relationship between log reduction of MNV-1 and time. D values of HHP inactivation of MNV-1 on green onions were 1.10 and 0.61min at 300 and 350MPa, respectively. The D value of HHP inactivation of MNV-1 in salsa at 300MPa was 0.63min. HHP inactivation of HuNoV GI.1 and GII.4 on green onions and salsa was also conducted. To achieve >3 log reduction of HuNoV GI.1, HHP treatments for 2min at 1°C should be conducted at 600MPa and 500MPa for green onions and salsa, respectively. To achieve >3 log reduction of HuNoV GII.4, HHP treatments for 2min at 1°C should be conducted at 500MPa and 300MPa for green onions and salsa, respectively.

      PubDate: 2016-11-17T08:07:01Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.003
      Issue No: Vol. 242 (2016)
  • Antimicrobial effect of emulsion-encapsulated isoeugenol against biofilms
           of food pathogens and spoilage bacteria
    • Authors: Christina Krogsgård Nielsen; Jørgen Kjems; Tina Mygind; Torben Snabe; Karin Schwarz; Yvonne Serfert; Rikke Louise Meyer
      Pages: 7 - 12
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): Christina Krogsgård Nielsen, Jørgen Kjems, Tina Mygind, Torben Snabe, Karin Schwarz, Yvonne Serfert, Rikke Louise Meyer
      Food-related biofilms can cause food-borne illnesses and spoilage, both of which are problems on a global level. Essential oils are compounds derived from plant material that have a potential to be used in natural food preservation in the future since they are natural antimicrobials. Bacterial biofilms are particularly resilient towards biocides, and preservatives that effectively eradicate biofilms are therefore needed. In this study, we test the antibacterial properties of emulsion-encapsulated and unencapsulated isoeugenol against biofilms of Lis. monocytogenes, S. aureus, P. fluorescens and Leu. mesenteroides in tryptic soy broth and carrot juice. We show that emulsion encapsulation enhances the antimicrobial properties of isoeugenol against biofilms in media but not in carrot juice. Some of the isoeugenol emulsions were coated with chitosan, and treatment of biofilms with these emulsions disrupted the biofilm structure. Furthermore, we show that addition of the surfactant Tween 80, which is commonly used to disperse oils in food, hampers the antibacterial properties of isoeugenol. This finding highlights that common food additives, such as surfactants, may have an adverse effect on the antibacterial activity of preservatives. Isoeugenol is a promising candidate as a future food preservative because it works almost equally well against planktonic bacteria and biofilms. Emulsion encapsulation has potential benefits for the efficacy of isoeugenol, but the effect of encapsulation depends on the properties of food matrix in which isoeugenol is to be applied.

      PubDate: 2016-11-17T08:07:01Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.002
      Issue No: Vol. 242 (2016)
  • Microbial counts of mealworm larvae (Tenebrio molitor) and crickets
           (Acheta domesticus and Gryllodes sigillatus) from different rearing
           companies and different production batches
    • Authors: D. Vandeweyer; S. Crauwels; B. Lievens; L. Van Campenhout
      Pages: 13 - 18
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): D. Vandeweyer, S. Crauwels, B. Lievens, L. Van Campenhout
      The rising interest in insects for human consumption and the changing regulations in Europe require a profound insight into the food safety of insects reared and sold in Western society. The microbial quality of edible insects has only been studied occasionally. This study aimed at generating an overview of intrinsic parameters (pH, water activity and moisture content) and microbial quality of fresh mealworm larvae and crickets for several rearing companies and for several batches per rearer. In total, 21 batches obtained from 7 rearing companies were subjected to analysis of intrinsic parameters, a range of plate counts and presence-absence tests for Salmonella spp. and Listeria monocytogenes. The microbial counts of the fresh insects were generally high. Different rearing batches from a single rearing company showed differences in microbial counts which could not be explained by variations in intrinsic properties. The largest variations were found in numbers of bacterial endospores, psychrotrophs and fungi. Salmonella spp. and L. monocytogenes were not detected in any of the samples. Altogether, our study shows that large variations were found between batches from individual rearers. As a consequence, no overall differences between rearers could be observed.

      PubDate: 2016-11-17T08:07:01Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.007
      Issue No: Vol. 242 (2016)
  • In vitro fermentation of different fructo-oligosaccharides by
           Bifidobacterium strains for the selection of synbiotic combinations
    • Authors: Lorena Valdés-Varela; Patricia Ruas-Madiedo; Miguel Gueimonde
      Pages: 19 - 23
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): Lorena Valdés-Varela, Patricia Ruas-Madiedo, Miguel Gueimonde
      The use of selected probiotics, prebiotics and/or synbiotics, constitute an interesting dietary strategy for intestinal microbiota modulation in case of dysbiosis. Species of the genus Bifidobacterium are among the most currently used probiotics for human consumption since they have shown beneficial effects in the prevention and treatment of some disorders. Bifidobacteria are saccharolytic microorganisms, but their ability to use different carbohydrates varies among strains. In this study, we investigate the utilization of three prebiotic substrates (two different short-chain fructo-oligosaccharides [scFOS] and inulin) by strains of Bifidobacterium, in order to determine the synbiotic potential of the different probiotic/prebiotic combinations. Batch culture fermentations from six Bifidobacterium strains (Bifidobacterium longum IPLA20021, B. longum IPLA20022, Bifidobacterium animalis IPLA20031, B. animalis IPLA20032, B. animalis IPLA20020 and B. animalis Bb12) were carried out in the presence of inulin or scFOS (Synergy or Actilight), or glucose, as carbon source. Bifidobacteria levels were quantified by plate counting. The pH and production of organic acids in the different batch-culture fermentations were also determined. Our results showed that all the studied strains of B. animalis and B. longum were able to utilize scFOS but not inulin. The use of scFOS as carbon source affected the pattern of metabolite's production, when compared with cultures carried out in glucose, particularly in the case of B. longum. The results indicated that the scFOS are well suited to be used in combination with B. animalis or B. longum strains for the development of synbiotic foods or food supplements.

      PubDate: 2016-11-23T08:18:11Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.011
      Issue No: Vol. 242 (2016)
  • Study of the bacterial diversity of foods: PCR-DGGE versus LH-PCR
    • Authors: Cristiana Garofalo; Elena Bancalari; Vesna Milanović; Federica Cardinali; Andrea Osimani; Maria Luisa Savo Sardaro; Benedetta Bottari; Valentina Bernini; Lucia Aquilanti; Francesca Clementi; Erasmo Neviani; Monica Gatti
      Pages: 24 - 36
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): Cristiana Garofalo, Elena Bancalari, Vesna Milanović, Federica Cardinali, Andrea Osimani, Maria Luisa Savo Sardaro, Benedetta Bottari, Valentina Bernini, Lucia Aquilanti, Francesca Clementi, Erasmo Neviani, Monica Gatti
      The present study compared two culture-independent methods, polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) and length-heterogeneity polymerase chain reaction (LH-PCR), for their ability to reveal food bacterial microbiota. Total microbial DNA and RNA were extracted directly from fourteen fermented and unfermented foods, and domain A of the variable regions V1 and V2 of the 16S rRNA gene was analyzed through LH-PCR and PCR-DGGE. Finally, the outline of these analyses was compared with bacterial viable counts obtained after bacterial growth on suitable selective media. For the majority of the samples, RNA-based PCR-DGGE revealed species that the DNA-based PCR-DGGE was not able to highlight. When analyzing either DNA or RNA, LH-PCR identified several lactic acid bacteria (LAB) and coagulase negative cocci (CCN) species that were not identified by PCR-DGGE. This phenomenon was particularly evident in food samples with viable loads<5.0 Logcfug−1. Furthermore, LH-PCR was able to detect a higher number of peaks in the analyzed food matrices relative to species identified by PCR-DGGE. In light of these findings, it may be suggested that LH-PCR shows greater sensitivity than PCR-DGGE. However, PCR-DGGE detected some other species (LAB included) that were not detected by LH-PCR. Therefore, certain LH-PCR peaks not attributed to known species within the LH-PCR database could be solved by comparing them with species identified by PCR-DGGE. Overall, this study also showed that LH-PCR is a promising method for use in the food microbiology field, indicating the necessity to expand the LH-PCR database, which is based, up to now, mainly on LAB isolates from dairy products.

      PubDate: 2016-11-23T08:18:11Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.008
      Issue No: Vol. 242 (2016)
  • Prevalence and molecular characterization of Clostridium difficile
           isolates from a pig slaughterhouse, pork, and humans in Taiwan
    • Authors: Ying-Chen Wu; Chih-Ming Chen; Chih-Jung Kuo; Jen-Jie Lee; Pin-Chun Chen; Yi-Chih Chang; Ter-Hsin Chen
      Pages: 37 - 44
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): Ying-Chen Wu, Chih-Ming Chen, Chih-Jung Kuo, Jen-Jie Lee, Pin-Chun Chen, Yi-Chih Chang, Ter-Hsin Chen
      Clostridium difficile causes antibiotic-associated diarrhea in both humans and animals. The ribotype 078, predominant in food animals, is associated with community-acquired C. difficile infection, and C. difficile is suggested to be a foodborne pathogen. Recently, the C. difficile ribotype 078 lineage emerged in patients and pigs in Taiwan. This study aimed to investigate the prevalence and molecular characterization of C. difficile isolated from a pig slaughterhouse, retail meat, ready-to-eat meals, and humans in Taiwan. We collected samples from one slaughterhouse (n =422), 29 retail markets (raw pork, n =62; ready-to-eat pork, n =65), and one hospital (non-diarrheal humans, stool, n =317) in 2015. The isolated C. difficile were subjected to ribotyping and multilocus variable-number tandem-repeat analysis (MLVA). In the slaughterhouse, the isolation rate from carcasses was high (23%, 21/92) and ribotype 126 dominated. Scalding water was found to have C. difficile contamination (44%, 4/9), and two of the seven isolates were ribotype 126. The isolation rates from raw pork and ready-to-eat pork were between 20% and 29%. Ribotypes 126, 127, and 014 were found in raw pork, whereas ribotype 078 was not identified in this study. Eight isolates—seven non-toxigenic isolates and one ribotype 017—were found in non-diarrheal human samples. Notably, MLVA showed that ribotype 126 isolates from the slaughterhouse, pig stool, colons, carcasses, and scalding water were closely genetically related, indicating serious risk for cross-contamination. However, the genetic evidence of foodborne transmission from carcasses to food and humans is still lacking.

      PubDate: 2016-11-23T08:18:11Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.010
      Issue No: Vol. 242 (2016)
  • Effect of ammonium and amino acids on the growth of selected strains of
           Gluconobacter and Acetobacter
    • Authors: F. Sainz; A. Mas; M.J. Torija
      Pages: 45 - 52
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): F. Sainz, A. Mas, M.J. Torija
      Acetic acid bacteria (AAB) are a group of microorganisms highly used in the food industry. However, its use can be limited by the insufficient information known about the nutritional requirements of AAB for optimal growth. The aim of this work was to study the effects of different concentrations and sources of nitrogen on the growth of selected AAB strains and to establish which nitrogen source best encouraged their growth. Two strains of three species of AAB, Gluconobacter japonicus, Gluconobacter oxydans and Acetobacter malorum, were grown in three different media with diverse nitrogen concentrations (25, 50, 100, and 300mgN/L and 1gN/L) as a complete solution of amino acids and ammonium. With this experiment, the most favourable medium and the lowest nitrogen concentration beneficial for the growth of each strain was selected. Subsequently, under these conditions, single amino acids or ammonium were added to media individually to determine the best nitrogen sources for each AAB strain. The results showed that nitrogen requirements are highly dependent on the nitrogen source, the medium and the AAB strain. Gluconobacter strains were able to grow in the lowest nitrogen concentration tested (25mgN/L); however, one of the G. oxydans strains and both A. malorum strains required a higher concentration of nitrogen (100–300mgN/L) for optimal growth. In general, single nitrogen sources were not able to support the growth of these AAB strains as well as the complete solution of amino acids and ammonium.

      PubDate: 2016-11-23T08:18:11Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.006
      Issue No: Vol. 242 (2016)
  • Influence of temperature, water activity and incubation time on fungal
           growth and production of ochratoxin A and zearalenone by toxigenic
    • Authors: Amani Lahouar; Sonia Marin; Ana Crespo-Sempere; Salem Saïd; Vicente Sanchis
      Pages: 53 - 60
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): Amani Lahouar, Sonia Marin, Ana Crespo-Sempere, Salem Saïd, Vicente Sanchis
      The major objective of this study was to describe the effect of water activity and temperature on radial growth and production of ochratoxin A (OTA) and zearalenone (ZEA) on sorghum grains of three Aspergillus tubingensis and three Fusarium incarnatum isolates. The water activity range was 0.91–0.99 aw for F. incarnatum isolates and 0.88–0.99 aw for A. tubingensis isolates. Temperatures of incubation were 15, 25 and 37°C for both species. Mycotoxin production was determined after 7, 14, 21 and 28days depending on the growth rate of the six isolates. Maximum growth rates (mm/day) were observed at 37°C and 0.99 aw for A. tubingensis isolates and at 0.99 aw and 25°C for F. incarnatum isolates. A. tubingensis was able to grow at 15°C only at the highest aw levels (0.97 and 0.99 aw). However, at this temperature F. incarnatum grew at 0.94 aw. Optimum ochratoxin A production was observed at 0.97 aw ×37°C whereas optimal conditions for ZEA production varied from one isolate to another. Moreover, isolates of F. incarnatum from Tunisia do not require high aw and temperature levels to yield maximum levels of ZEA. In general, our results showed that there is no correlation between the growth and production of ZEA in the case of F. incarnatum. This is the first study on the water activity and temperature effect on growth rate and ZEA production of F. incarnatum. Our results show that sorghum grains not only support growth but also OTA and ZEA production by A. tubingensis and F. incarnatum, respectively.

      PubDate: 2016-11-23T08:18:11Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.015
      Issue No: Vol. 242 (2016)
  • Genetic and transcriptional study of glutathione metabolism in Oenococcus
    • Authors: Mar Margalef-Català; Isabel Araque; Albert Bordons; Cristina Reguant
      Pages: 61 - 69
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): Mar Margalef-Català, Isabel Araque, Albert Bordons, Cristina Reguant
      Although Oenococcus oeni is the main species that is responsible for malolactic fermentation (MLF), harsh wine conditions can limit its performance. Although several mechanisms underlying the response to stress have been studied in this species, little is known regarding the cellular systems that protect against oxidative stress in other bacteria, such as glutathione (GSH). O. oeni cannot synthesize GSH but contains several genes related to its utilization. In this study, the relative expression (RE) of the seven genes involved in the GSH redox system found in O. oeni PSU-1 (gshR, gpo, three glutaredoxin-like genes and two subunits of an hypothetical transporter) has been measured. The study was performed using three strains, with each exhibiting a different GSH uptake capacity. The strains were grown in a stress-adaptation medium supplemented with 5mM GSH and under different adaptation stress conditions (pH4 and 6% ethanol). The RE showed that only some of these genes, including one for a possible glutaredoxin (OEOE_RS04215) and cydC for a subunit of a putative GSH transporter (OEOE_RS1995), responded to the addition of GSH. The presence of ethanol had a relevant effect on gene expression. Among the studied genes, the one for a NrdH-redoxin (OEOE_RS00645) showed a common response to ethanol in the strains, being over-expressed when grown with GSH. In most cases, the transcriptional changes were more evident for the strain with a higher capacity of GSH uptake. Malolactic performance of the three strains after pre-adaptation was evaluated in wine-like media (12% ethanol and pH3.4). It was observed that the addition of GSH during pre-adaptation growth had a protective role in the cells exposed to low pH and ethanol, resulting in a quicker MLF.

      PubDate: 2016-12-01T07:14:43Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.013
      Issue No: Vol. 242 (2016)
  • Study of Streptococcus thermophilus population on a world-wide and
           historical collection by a new MLST scheme
    • Authors: Christine Delorme; Nicolas Legravet; Emmanuel Jamet; Caroline Hoarau; Bolotin Alexandre; Walid M. El-Sharoud; Mohamed S. Darwish; Pierre Renault
      Pages: 70 - 81
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): Christine Delorme, Nicolas Legravet, Emmanuel Jamet, Caroline Hoarau, Bolotin Alexandre, Walid M. El-Sharoud, Mohamed S. Darwish, Pierre Renault
      We analyzed 178 Streptococcus thermophilus strains isolated from diverse products, from around the world, over a 60-year period with a new multilocus sequence typing (MLST) scheme. This collection included isolates from two traditional cheese-making sites with different starter-use practices, in sampling campaigns carried out over a three years period. The nucleotide diversity of the S. thermophilus population was limited, but 116 sequence types (ST) were identified. Phylogenetic analysis of the concatenated sequences of the six housekeeping genes revealed the existence of groups confirmed by eBURST analysis. Deeper analyses performed on 25 strains by CRISPR and whole-genome analysis showed that phylogenies obtained by MLST and whole-genome analysis were in agreement but differed from that inferred by CRISPR analysis. Strains isolated from traditional products could cluster in specific groups indicating their origin, but also be mixed in groups containing industrial starter strains. In the traditional cheese-making sites, we found that S. thermophilus persisted on dairy equipment, but that occasionally added starter strains may become dominant. It underlined the impact of starter use that may reshape S. thermophilus populations including in traditional products. This new MLST scheme thus provides a framework for analyses of S. thermophilus populations and the management of its biodiversity.

      PubDate: 2016-12-01T07:14:43Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.016
      Issue No: Vol. 242 (2016)
  • Association between pigs with high caecal Salmonella loads and carcass
    • Authors: M. Pesciaroli; L. Cucco; S. De Luca; F.R. Massacci; C. Maresca; L. Medici; M. Paniccià; E. Scoccia; M. Staffolani; G. Pezzotti; C.F. Magistrali
      Pages: 82 - 86
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): M. Pesciaroli, L. Cucco, S. De Luca, F.R. Massacci, C. Maresca, L. Medici, M. Paniccià, E. Scoccia, M. Staffolani, G. Pezzotti, C.F. Magistrali
      Contaminated pork is a significant source of foodborne Salmonella infections. Pork is contaminated at the slaughterhouse; however, the mechanisms driving Salmonella contamination of carcasses are still poorly understood. The aim of this study was to investigate whether the amount of Salmonella carried by slaughtered pigs in their guts has an influence on carcass contamination. On that account, we tested whether the number of carcasses contaminated during a slaughter day was associated with the prevalence of highly contaminated pigs (HCP: Salmonella caecal loads ≥3log/g), or with the prevalence of pigs that simply carry Salmonella spp. in their guts. Three hundred and six pigs were sampled in a slaughterhouse from Central Italy. Salmonella loads in the caecum and on the carcass of each pig were estimated by the most probable number (MPN) technique. The overall prevalence of Salmonella was 34.64% and 7.19% for the caeca and carcasses, respectively. S. Derby and S. 4, (Bonardi et al., 2003),12:i:- were the most frequently isolated serovars. The prevalence of HCP was 11.44%. We found a higher number of contaminated carcasses on days of high prevalence of HCP than on days of low prevalence of HCP (p =0.0011). Conversely, carcass contamination did not vary with the prevalence of pigs that simply carried Salmonella spp. in their guts (p =0.7970). Therefore, the prevalence of HCP, but not the prevalence of pigs carrying Salmonella spp., was related to carcass contamination. Taken together, these findings suggest that reduction of Salmonella loads in the guts of slaughtered pigs would result in fewer contaminated carcasses, and consequently, help to minimise the risk of human infection due to the consumption of contaminated pork.

      PubDate: 2016-12-08T04:23:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.021
      Issue No: Vol. 242 (2016)
  • Quantitative farm-to-fork human norovirus exposure assessment of
           individually quick frozen raspberries and raspberry puree
    • Authors: L. Jacxsens; A. Stals; A. De Keuckelaere; B. Deliens; A. Rajkovic; M. Uyttendaele
      Pages: 87 - 97
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): L. Jacxsens, A. Stals, A. De Keuckelaere, B. Deliens, A. Rajkovic, M. Uyttendaele
      A quantitative human norovirus (NoV) exposure model describing transmission of NoV during pre-harvest, harvest and further processing of soft red fruits exemplified by raspberries is presented. The outcomes of the model demonstrate the presence of NoV in raspberry puree or individual quick frozen (IQF) raspberry fruits and were generated by Monte Carlo simulations by combining GoldSim® and @Risk® software. Input data were collected from scientific literature, observational studies and assumptions. NoV contamination of soft red fruits is assumed to take place at farms by application of contaminated water for pesticides dilution or by berries' pickers shedding NoV. The model was built simulating that a collection center received berries from ten farms with a total of 245 food handlers picking soft red fruits during a 10-hour day shift. Given 0, 5 and 20 out of 245 berries' pickers were shedding NoV, these conditions were calculated to result in a mean NoV contamination of respectively 0.47, 14.1 and 36.2 NoV particles per kg raspberries in case all raspberries are mixed to one day-batch of 11tons. The NoV contamination of the fruits was mainly driven by the route of NoV shedding food pickers (95.8%) rather than by spraying contaminated pesticide water (4.2%) (baseline scenario with 5 shedding pickers and contaminated pesticide water). Inclusion of appropriate hand washing procedures or hand washing followed by hand disinfection resulted in estimated reductions of the mean NoV levels from 14.1 to 0.16 and 0.17 NoV particles per kg raspberries, respectively, for the baseline scenario with 5 out of 245 food pickers shedding NoV. The use of a mild heat treatment (30s at 75°C) during further processing of berries to purees was noted to reduce mean NoV levels substantially from 14.1 to 0.2 NoV particles per kg raspberry puree. For IQF raspberries, the NoV contamination is heterogeneously distributed and resulted in a mean contamination of 3.1 NoV particles per 250g package containing approximately 115 berries. This farm-to-fork model is a useful tool for evaluating NoV mitigation strategies in the soft red fruit supply chain.

      PubDate: 2016-12-08T04:23:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.019
      Issue No: Vol. 242 (2016)
  • Development and validation of species-specific molecular diagnostic tool
           for Opisthorchis felineus (Digenea, Opisthorchiidae) metacercariae
    • Authors: Monica Caffara; Laura Serracca; Andrea Gustinelli; Walter Vencia; Irene Rossini; Marino Prearo; Maria L. Fioravanti
      Pages: 98 - 100
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): Monica Caffara, Laura Serracca, Andrea Gustinelli, Walter Vencia, Irene Rossini, Marino Prearo, Maria L. Fioravanti
      Opisthorchis felineus (family Opisthorchiidae) is a parasitic flatworm representing a serious threat to humans in some countries. Opisthorchiasis occurs after consumption of raw or undercooked cyprinid fish infected by the metacercarial stage of the parasite. Due to its small size, detection of the parasite in fish fillet is time-consuming and difficult. Furthermore, isolated metacercariae can be identified to genus but not to species level using morphological features and molecular techniques are necessary. In this work, we describe the development of primers for a diagnostic PCR amplification of a 254-bp fragment of the cytochrome c oxidase I in the mitochondrion of Opisthorchis felineus metacercariae isolated from fish fillet, together with a validation protocol for this method.

      PubDate: 2016-12-08T04:23:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.024
      Issue No: Vol. 242 (2016)
  • Tracking Listeria monocytogenes contamination and virulence-associated
           characteristics in the ready-to-eat meat-based food products industry
           according to the hygiene level
    • Authors: A.R. Henriques; L.T. Gama; M.J. Fraqueza
      Pages: 101 - 106
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): A.R. Henriques, L.T. Gama, M.J. Fraqueza
      Listeria monocytogenes isolates collected from final products and food contact surfaces of 10 ready-to-eat meat-based food products (RTEMP) producing industries were analyzed to relate their virulence-associated characteristics and genetic profiles with the hygiene assessment of those industries. Together with sample collection, an audit was performed to evaluate the implemented food safety management system and to investigate the specific audit requisites more associated to the occurrence of those L. monocytogenes serogroups frequently related with human disease. L. monocytogenes was present in 18% of the samples. The isolates (n =62) were serogrouped and detection of virulence-associated genes inlA, inlB, inlC and inlJ, and also plcA, hlyA, actA and iap was done by multiplex PCR. After this initial characterization, selected isolates (n =31) were submitted to antibiotic resistance testing by the disk diffusion method for the currently most used human and veterinary antibiotics and resistance was low. These isolates were also subtyped by pulsed-field gel electrophoresis. Genotyping and serogrouping of L. monocytogenes isolates revealed a genetically diverse population. Our data indicate that contamination of final products does not seem to be uniquely related to the sampled food surfaces. The occurrence of those L. monocytogenes serogroups more commonly associated with human disease in industries with a high hygienic audit classification could be the result of a previous identification of the pathogen, with an enforcement of the hygiene program without recognizing the real source of contamination. This reinforces the importance of a conjoined diagnosis using audit data and microbiological testing. Food safety management systems of those industries need improvement, particularly in cleaning and sanitizing operations, analytical control, preventive maintenance, personal hygiene and root cause analysis.

      PubDate: 2016-12-08T04:23:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.020
      Issue No: Vol. 242 (2016)
  • Assessment of the risk of foodborne transmission and burden of hepatitis E
           in Switzerland
    • Authors: Alexandra Müller; Lucie Collineau; Roger Stephan; Andrea Müller; Katharina D.C. Stärk
      Pages: 107 - 115
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): Alexandra Müller, Lucie Collineau, Roger Stephan, Andrea Müller, Katharina D.C. Stärk
      The objective of this study was i) to quantify the risk of hepatitis E for Swiss consumers by specified pork products and ii) to estimate the total burden of human food-borne hepatitis E in Switzerland. A quantitative risk assessment from slaughter to consumption was carried out according to the Codex Alimentarius framework. In the hazard characterization, assumptions were made due to the lack of a dose-response relationship for oral exposure to hepatitis E virus (HEV). The prevalence of HEV in 160 pig livers of 40 different Swiss fattening farms was examined and determined to be 1.3% (CI 0.3%; 4.4%). This result was used as input in the risk assessment model, together with data from other published studies. The annual burden of hepatitis E was estimated in terms of Disability Adjusted Life Years (DALY), using data about hepatitis E cases diagnosed between 2010 and 2015 at two major hospitals located in the canton Ticino. Only the risk of foodborne hepatitis E from products containing pork liver was evaluated, as those containing only pork meat could not be evaluated because of lack of data on HEV load in pork. Assuming that successful oral infection occurs in 1% of servings contaminated with high HEV loads (>105 genome copies), and that acute illness develops in 5% of susceptible consumers, the most likely annual number of foodborne hepatitis E cases in Switzerland was estimated to be 1481 (95% CI 552; 4488) if all products containing pork liver were considered. If only high-risk products, such as plain pork liver and liver sausages (e.g. Saucisse au Foie), were considered, the annual number of cases was estimated to be 176 (95% CI 64; 498). We were unable to calculate the total burden of hepatitis E in Switzerland due to lack of data. Yet, for the canton Ticino, it was shown that a significant increase had occurred from <5 DALY per 100,000 inhabitants before 2012 to >50 DALY per 100,000 inhabitants in 2015. This change could partly be due to an increased reporting and higher awareness among medical practitioners. Extrapolation to other regions could be accomplished if detailed information on food consumption patterns were available. Notification of HEV cases and attempts of cases source attribution would improve the basis for risk assessments.

      PubDate: 2016-12-08T04:23:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.018
      Issue No: Vol. 242 (2016)
  • Occurrence and ecological distribution of Heat Resistant Moulds Spores
           (HRMS) in raw materials used by food industry and thermal characterization
           of two Talaromyces isolates
    • Authors: Roberta Tranquillini; Nicoletta Scaramuzza; Elettra Berni
      Pages: 116 - 123
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): Roberta Tranquillini, Nicoletta Scaramuzza, Elettra Berni
      In this study, screening of some raw materials used to produce pasteurized products was carried out to determine the occurrence and ecological distribution of heat-resistant fungi. The search for Heat Resistant Mould Spores (HRMS) resulted in the isolation of a limited number of fungal genera: Arthrinium, Aspergillus with either Eurotium-type or Neosartorya-type ascoma, Byssochlamys, Hyphodermella, Monascus, Penicillium, Rasamsonia, Talaromyces and Thermoascus. Sexual aspergilli constituted an overwhelming percentage of the mycobiota, totaling 93.5% of the heat-resistant fungi detected, and being the only fungi to be simultaneously detected in discrete concentrations on almost all matrices found positive for HRMS. Talaromyces spp., Penicillium spp. and Monascus sp. occurred at low percentages (up to 2.1%), though they were the most commonly occurring genera in lemon cells (Talaromyces, Monascus) and blueberries (Penicillium spp.). Among these isolates, two Talaromyces spp. (T. trachyspermus and T. bacillisporus) were tested for heat-resistance in both blueberry and grape juice or in buffered glucose solution, in order to assess their D- and z-values. Data obtained from thermal death curves and statistical elaboration of raw data showed that D-values of T. trachyspermus ranged between 50.0 and 90.9min at 75°C; 13.6 and 20.8min at 78°C; 5.1 and 12.4min at 80°C; 1.6 and 2.6min at 82°C. D values of T. bacillisporus ranged between 44.4 and 60.9min at 82°C; 11.9 and 15.5min at 85°C; 2.7 and 4.1min at 88°C and were equal to 1.2min at 91°C, depending on the medium. The heating times needed for inactivation were comparable to those applied to most heat-resistant species, but significantly lower than those applied to Talaromyces macrosporus or less common ascospore-forming fungal species such as Hamigera avellanea and Thermoascus crustaceus. Therefore, a traditional pasteurization process would be insufficient to avoid potential spoilage problems with T. trachyspermus or T. bacillisporus, even if HRMS contamination of the raw materials processed by food industries is generally low (<100CFU/kg), since the food industry generally tries to achieve five or more log-reduction in their products.

      PubDate: 2016-12-22T15:57:11Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.023
      Issue No: Vol. 242 (2016)
  • Functional food applications of dextran from Weissella cibaria RBA12 from
           pummelo (Citrus maxima)
    • Authors: Rwivoo Baruah; Ndegwa H. Maina; Kati Katina; Riikka Juvonen; Arun Goyal
      Pages: 124 - 131
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): Rwivoo Baruah, Ndegwa H. Maina, Kati Katina, Riikka Juvonen, Arun Goyal
      Weissella cibaria RBA12 isolated from pummelo from Northeast India produces a dextran composed of 97% α-(1→6) linkages in the main chain and 3% α-(1→3) branched linkages. The in vitro prebiotic activity of dextran-RBA12 was explored. Dextran-RBA12 displayed enhanced growth of probiotic Bifidobacterium and Lactobacillus spp., and controlled growth of non-probiotic enteric bacteria. Dextran-RBA12 showed superior resistance to physiological barriers with a maximum hydrolysis of 0.51%, 0.31% and 0.24% by artificial gastric juice, α–amylase and intestinal fluid, respectively, whereas compared to maximum hydrolysis of 25.23%, 19.13% and 6%, respectively after 5h of incubation shown by commercial prebiotic inulin. The production of dextran from Weissella cibaria RBA12 in sourdough prepared from whole wheat flour, wheat bran and rye bran showed the highest dextran of 3.26±0.12% d.w. in rye bran. The overall study summarized that dextran-RBA12 can be used as a prebiotic and also can be easily produced in sourdough.

      PubDate: 2016-12-22T15:57:11Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.012
      Issue No: Vol. 242 (2016)
  • Detection of different microenvironments and Lactobacillus sakei biotypes
           in Ventricina, a traditional fermented sausage from central Italy
    • Authors: Patrizio Tremonte; Elena Sorrentino; Gianfranco Pannella; Luca Tipaldi; Marina Sturchio; Armando Masucci; Lucia Maiuro; Raffaele Coppola; Mariantonietta Succi
      Pages: 132 - 140
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): Patrizio Tremonte, Elena Sorrentino, Gianfranco Pannella, Luca Tipaldi, Marina Sturchio, Armando Masucci, Lucia Maiuro, Raffaele Coppola, Mariantonietta Succi
      The present study evaluated the physico-chemical and microbiological features of Ventricina, considering for the first time the presence of different compartments deriving from the technology of production. In fact meat pieces (pork muscle and fat cut into cubes of about 10–20cm3), mixed with other ingredients and then stuffed into pig bladder, are still distinguishable at the end of the ripening. They appear delimited on the outside by the casing and inside by thin layers consisting of spices (mainly red pepper powder), salt and meat juices. Our results showed that the exterior (portion of the product in contact with the casing), the interstice (area between the different cubes of meat or fat) and the heart (the inner portion of meat cubes) had distinctive values of pH and aw, and a typical microbial progression, so that they can be considered as different ecological niches, here called microenvironments. The study of lactic acid bacteria population, performed with PCR-DGGE and sequence analysis targeting the V1–V3 region of the 16S rRNA gene (rDNA), highlighted the presence of a few species, including Lactobacillus sakei, Lb. plantarum, Weissella hellenica and Leuconostoc mesenteroides. The RAPD-PCR analysis performed on Lb. sakei, recognised as the predominant species, allowed the differentiation into three biotypes, with that characterised by the highest acidifying and proteolytic activities and the highest ability to grow in the presence of sodium chloride prevailing. This leading biotype, detectable in the interstice during the entire ripening period, was isolated in the microenvironments exterior and heart starting from the 30th d of ripening, and it was the sole biotype present at the end of the ripening. The analysis of microenvironments through the scanning electron microscopy (SEM) evidenced the presence of micro-channels, which could favour the microbial flow from the interstice to the exterior and the heart. Moreover, the SEM analysis allowed the detection of biofilms, recognised as responsible for the correct colonisation of the different meat niches.

      PubDate: 2016-12-22T15:57:11Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.009
      Issue No: Vol. 242 (2016)
  • Predominant processing adaptability of Staphylococcus xylosus strains
           isolated from Chinese traditional low-salt fermented whole fish
    • Authors: Xuefeng Zeng; Laping He; Xu Guo; Li Deng; Wangen Yang; Qiujin Zhu; Zhenhua Duan
      Pages: 141 - 151
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): Xuefeng Zeng, Laping He, Xu Guo, Li Deng, Wangen Yang, Qiujin Zhu, Zhenhua Duan
      This study aimed to determine the predominant processing adaptability of 27 selected isolates of Staphylococcus xylosus in ‘Suan yu’, a traditional Chinese low-salt fermented whole-fish product. The isolates were screened for proteolytic, lipolytic, and enzymatic profiles; amino-acid decarboxylase content; antimicrobial activities; and tolerance to low temperatures, pH5.0, and salt. Two S. xylosus strains grew at 10°C in the presence of 10% NaCl and at pH5.0. Agar-plate assays and sodium dodecyl sulphate–polyacrylamide gel electrophoresis revealed that 21 and 8 of the strains exhibited appropriate proteolytic activities against myofibrillar and sarcoplasmic proteins, respectively. All S. xylosus strains also displayed different enzymatic profiles, and most strains showed negative decarboxylase activities. The results of this step were used as input data for a Principal Component Analysis; therefore, the most technologically relevant strain 3 and 8 were combined with L. plantarum 120 as MS1 and MS2, respectively, were further selected for the fermented fish surimi, and the fish surimi inoculated with mixed starter cultures (MS1, MS2) scored high for overall acceptability. Free amino acid contents of 1757 and 1765mg/100g sample were found in fish surimi inoculated with MS1 and MS2, respectively, after 72h of fermentation. Therefore, Sx-3 and Sx-8, which presented the best predominant processing adaptability, is an eligible starter culture for fermented fish production.

      PubDate: 2016-12-22T15:57:11Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.014
      Issue No: Vol. 242 (2016)
School of Mathematical and Computer Sciences
Heriot-Watt University
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