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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: 15)
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: 33)
Antimicrobial Agents and Chemotherapy     Hybrid Journal   (Followers: 18)
Antiviral Research     Hybrid Journal   (Followers: 7)
Applied and Environmental Microbiology     Hybrid Journal   (Followers: 38)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 16)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 57)
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: 1)
Canadian Journal of Microbiology     Full-text available via subscription   (Followers: 3)
Cell Biology : Research & Therapy     Hybrid Journal   (Followers: 2)
Cell Host & Microbe     Full-text available via subscription   (Followers: 14)
Cell Medicine     Open Access   (Followers: 3)
Cell Regeneration     Open Access   (Followers: 1)
Cell Stem Cell     Full-text available via subscription   (Followers: 29)
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: 15)
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: 28)
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: 6)
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: 14)
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: 4)
Frontiers in Microbiology     Open Access   (Followers: 8)
Frontiers in Molecular Neuroscience     Open Access   (Followers: 2)
Future Microbiology     Full-text available via subscription   (Followers: 4)
Future Virology     Full-text available via subscription   (Followers: 7)
Gene Expression     Full-text available via subscription  
Genetica si Biologie Moleculara     Open Access  
Genetics and Molecular Research     Open Access   (Followers: 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: 6)
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)
JAMMI     Full-text available via subscription  
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: 10)
Journal of Bacteriology     Hybrid Journal   (Followers: 25)
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: 11)
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: 13)
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: 2)
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: 3)
Memórias do Instituto Oswaldo Cruz     Open Access  
Methods in Molecular Biology     Hybrid Journal   (Followers: 21)
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: 6)
Microbial Ecology in Health and Disease     Open Access  
Microbial Informatics and Experimentation     Open Access   (Followers: 1)
Microbial Pathogenesis     Hybrid Journal   (Followers: 6)
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: 4)
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: 26)

        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  [3038 journals]
  • Antifungal activity of 1-methylcyclopropene (1-MCP) against anthracnose
           (Colletotrichum gloeosporioides) in postharvest mango fruit and its
           possible mechanisms of action
    • Authors: Xiangbin Xu; Huanhuan Lei; Xiuyan Ma; Tongfei Lai; Hongmiao Song; Xuequn Shi; Jiangkuo Li
      Pages: 1 - 6
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Xiangbin Xu, Huanhuan Lei, Xiuyan Ma, Tongfei Lai, Hongmiao Song, Xuequn Shi, Jiangkuo Li
      Anthracnose caused by Colletotrichum gloeosporioides is one of the most important postharvest diseases in mango fruit, often causing huge economic losses. In this study, the effect of 1-methylcyclopropene (1-MCP) against anthracnose in postharvest mango fruit and the mechanisms involved were investigated. 1-MCP induced reactive oxygen species (ROS) generation, damaged the mitochondria and destroyed the integrity of plasma membrane of spores of C. gloeosporioides, significantly suppressing spore germination and mycelial growth of C. gloeosporioides. 1-MCP also decreased the decay incidence and lesion expansion of mango fruit caused by C. gloeosporioides. For the first time this study demonstrated that 1-MCP suppressed anthracnose of postharvest mango fruit by directly inhibiting spore germination and mycelial growth of C. gloeosporioides, thus providing a promising strategy for disease control.

      PubDate: 2016-10-14T15:35:30Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.002
      Issue No: Vol. 241 (2016)
  • Zygosaccharomyces rouxii strains CECT 11923 and Z. rouxii CECT 10425: Two
           new putative hybrids'
    • Authors: Petra Wrent; Eva-María Rivas; José M. Peinado; María-Isabel de Silóniz
      Pages: 7 - 14
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Petra Wrent, Eva-María Rivas, José M. Peinado, María-Isabel de Silóniz
      Based on IGS-PCR RFLP polymorphism, we previously detected two Z. rouxii strains (CECT 11923 and CECT 10425) that clustered with hybrid strains (NCYC 1682, NCYC 3060 and NCYC 3061). Given the recently recognized important industrial role of hybrids, their detection is very useful. Based on the IGS1 rDNA region alignment of hybrid strains and the Z. rouxii CECT 11923 and CECT 10425, in this work, we developed a pair of Zygosaccharomyces hybrid-specific primers, HibZF/HibZR. Positive amplicons were only obtained in the Zygosaccharomyces spp. hybrids included in this study and the CECT 11923 and CECT 10425 strains analyzed here. In the present study, we applied molecular tools to highlight the nature of these strains; they are quite different from each other as well as from Z. rouxii type strain. Based on the presence of two heterologous copies of nuclear-encoded genes (SOD2 and HIS3), the sequences of divergent 5.8S-ITS rDNA, D1/D2 26S rDNA copies and, the amplification with species-specific primer for Z. rouxii and Z. pseudorouxii, we hypothesize that the CECT 11923 strain might be a hybrid strain. Whereas, CECT 10425, the sequence analysis of 5.8S-ITS rDNA and D1/D2 26S rDNA copies presented 99–100% sequence identity with Zygosaccharomyces sp. NBRC 10669 (LN849119.1) and Z. sapae ABT 301T. Nevertheless, we discard that it could be a Z. sapae strain based on the results obtained in this study. Namely, the amplification with hybrid-specific primer designed in this study, the number of divergent copies of HIS3 (2), the fact that it only possesses one SOD2 gene and the amplification with species-specific primer for Z. pseudorouxii, therefore it could be a new species or a hybrid strain.

      PubDate: 2016-10-14T15:35:30Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.019
      Issue No: Vol. 241 (2016)
  • Comparative evaluation of direct plating and most probable number for
           enumeration of low levels of Listeria monocytogenes in naturally
           contaminated ice cream products
    • Authors: Yi Chen; Régis Pouillot; Laurel S. Burall; Errol A. Strain; Jane M. Van Doren; Antonio J. De Jesus; Anna Laasri; Hua Wang; Laila Ali; Aparna Tatavarthy; Guodong Zhang; Lijun Hu; James Day; Ishani Sheth; Jihun Kang; Surasri Sahu; Devayani Srinivasan; Eric W. Brown; Mickey Parish; Donald L. Zink; Atin R. Datta; Thomas S. Hammack; Dumitru Macarisin
      Pages: 15 - 22
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Yi Chen, Régis Pouillot, Laurel S. Burall, Errol A. Strain, Jane M. Van Doren, Antonio J. De Jesus, Anna Laasri, Hua Wang, Laila Ali, Aparna Tatavarthy, Guodong Zhang, Lijun Hu, James Day, Ishani Sheth, Jihun Kang, Surasri Sahu, Devayani Srinivasan, Eric W. Brown, Mickey Parish, Donald L. Zink, Atin R. Datta, Thomas S. Hammack, Dumitru Macarisin
      A precise and accurate method for enumeration of low level of Listeria monocytogenes in foods is critical to a variety of studies. In this study, paired comparison of most probable number (MPN) and direct plating enumeration of L. monocytogenes was conducted on a total of 1730 outbreak-associated ice cream samples that were naturally contaminated with low level of L. monocytogenes. MPN was performed on all 1730 samples. Direct plating was performed on all samples using the RAPID'L.mono (RLM) agar (1600 samples) and agar Listeria Ottaviani and Agosti (ALOA; 130 samples). Probabilistic analysis with Bayesian inference model was used to compare paired direct plating and MPN estimates of L. monocytogenes in ice cream samples because assumptions implicit in ordinary least squares (OLS) linear regression analyses were not met for such a comparison. The probabilistic analysis revealed good agreement between the MPN and direct plating estimates, and this agreement showed that the MPN schemes and direct plating schemes using ALOA or RLM evaluated in the present study were suitable for enumerating low levels of L. monocytogenes in these ice cream samples. The statistical analysis further revealed that OLS linear regression analyses of direct plating and MPN data did introduce bias that incorrectly characterized systematic differences between estimates from the two methods.

      PubDate: 2016-10-14T15:35:30Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.021
      Issue No: Vol. 241 (2016)
  • Ultrasound improves chemical reduction of natural contaminant microbiota
           and Salmonella enterica subsp. enterica on strawberries
    • Authors: Denes Kaic Alves do Rosário; Yhan da Silva Mutz; Jaqueline Moreira Curtis Peixoto; Syllas Borburema Silva Oliveira; Raquel Vieira de Carvalho; Joel Camilo Souza Carneiro; Jackline Freitas Brilhante de São José; Patrícia Campos Bernardes
      Pages: 23 - 29
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Denes Kaic Alves do Rosário, Yhan da Silva Mutz, Jaqueline Moreira Curtis Peixoto, Syllas Borburema Silva Oliveira, Raquel Vieira de Carvalho, Joel Camilo Souza Carneiro, Jackline Freitas Brilhante de São José, Patrícia Campos Bernardes
      New sanitization methods have been evaluated to improve food safety and food quality and to replace chlorine compounds. However, these new methods can lead to physicochemical and sensory changes in fruits and vegetables. The present study evaluated the effects of acetic acid, peracetic acid, and sodium dodecylbenzenesulfonate isolated or combined with 5min of ultrasound treatment (40kHz, 500W) on strawberry quality over 9days of storage at 8°C. The strawberry natural contaminant microbiota (molds and yeasts, mesophilic aerobic and lactic acid bacteria), physicochemical quality (pH, total titratable acidity, total soluble solids, vitamin C, and color), sensory quality (triangle test) and inactivation of Salmonella enterica subsp. enterica intentionally inoculated onto strawberries were analyzed. Ultrasound increased the effect of all chemical compounds in the reduction of aerobic mesophilic, molds and yeasts. The best treatment for those groups of microorganisms was ultrasound combined with peracetic acid (US+PA) that reduced 1.8 and 2.0logcfu/g during 9days of storage. Bactericidal effect of peracetic acid was also improved by ultrasound inactivation of S. enterica, reaching a decimal reduction of 2.1logcfu/g. Moreover, synergistic effects were observed in contaminant natural microbiota inactivation for all tested compounds during storage, without any major physicochemical or sensory alteration to the strawberries. Therefore, ultrasound treatment can improve the effect of sanitizers that are substitutes of chlorine compounds without altering the quality of strawberries during storage. Acetic acid (PubChem CID: 176); Peracetic acid (PubChem CID: 6585); Sodium dodecylbenzenesulfonate (PubChem CID: 18372154).

      PubDate: 2016-10-14T15:35:30Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.009
      Issue No: Vol. 241 (2016)
  • Active edible coating and γ-irradiation as cold combined treatments to
           assure the safety of broccoli florets (Brassica oleracea L.)
    • Authors: Yosra Ben-Fadhel; Sabrina Saltaji; Mohamed Ali Khlifi; Stephane Salmieri; Khanh Dang Vu; Monique Lacroix
      Pages: 30 - 38
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Yosra Ben-Fadhel, Sabrina Saltaji, Mohamed Ali Khlifi, Stephane Salmieri, Khanh Dang Vu, Monique Lacroix
      The antimicrobial activity of essential oils (EOs), organic acid (OA) salts and natamycin, a natural antifungal produced during fermentation by the bacterium Streptomyces natalensis, was assessed against four pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium and Aspergillus niger). The Minimum Inhibitory Concentration (MIC) of each antimicrobial (AM) was assessed to determine their efficiency on tested microbial species in order to select the most efficient. Then, the interactions between different antimicrobial compounds showing the lowest MIC were determined by the checkerboard method. The most effective antimicrobial formulation showing synergistic or additive effects was then encapsulated in an alginate matrix to protect the antimicrobial efficiency during storage. The effectiveness of the formulation was then evaluated in situ using broccoli as a food model. A combined treatment of active coating and γ-irradiation (0.4 and 0.8kGy) was also done in order to evaluate the possible synergistic effect between treatments. The results of this study allowed the selection of 4 EOs, one OA salt and the natamycin as an antifungal agent exhibiting lower MIC values. The interactive antimicrobial effects between them showed that an antimicrobial formulation composed of 300ppm of lemongrass EO, 5000ppm of sodium diacetate and 80ppm of natamycin resulted in an additive effect against A. niger, E. coli and S. Typhimurium and showing synergistic effect against L. monocytogenes. Finally, in situ analyses showed a synergistic antimicrobial activity between active coating and γ-irradiation and allowed the extension of the shelf-life of ready-to-eat (RTE) broccoli during storage at 4°C.

      PubDate: 2016-10-14T15:35:30Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.010
      Issue No: Vol. 241 (2016)
  • Functional genomics provides insights into the role of Propionibacterium
           freudenreichii ssp. shermanii JS in cheese ripening
    • Authors: Teija Ojala; Pia K.S. Laine; Terhi Ahlroos; Jarna Tanskanen; Saara Pitkänen; Tuomas Salusjärvi; Matti Kankainen; Soile Tynkkynen; Lars Paulin; Petri Auvinen
      Pages: 39 - 48
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Teija Ojala, Pia K.S. Laine, Terhi Ahlroos, Jarna Tanskanen, Saara Pitkänen, Tuomas Salusjärvi, Matti Kankainen, Soile Tynkkynen, Lars Paulin, Petri Auvinen
      Propionibacterium freudenreichii is a commercially important bacterium that is essential for the development of the characteristic eyes and flavor of Swiss-type cheeses. These bacteria grow actively and produce large quantities of flavor compounds during cheese ripening at warm temperatures but also appear to contribute to the aroma development during the subsequent cold storage of cheese. Here, we advance our understanding of the role of P. freudenreichii in cheese ripening by presenting the 2.68-Mbp annotated genome sequence of P. freudenreichii ssp. shermanii JS and determining its global transcriptional profiles during industrial cheese-making using transcriptome sequencing. The annotation of the genome identified a total of 2377 protein-coding genes and revealed the presence of enzymes and pathways for formation of several flavor compounds. Based on transcriptome profiling, the expression of 348 protein-coding genes was altered between the warm and cold room ripening of cheese. Several propionate, acetate, and diacetyl/acetoin production related genes had higher expression levels in the warm room, whereas a general slowing down of the metabolism and an activation of mobile genetic elements was seen in the cold room. A few ripening-related and amino acid catabolism involved genes were induced or remained active in cold room, indicating that strain JS contributes to the aroma development also during cold room ripening. In addition, we performed a comparative genomic analysis of strain JS and 29 other Propionibacterium strains of 10 different species, including an isolate of both P. freudenreichii subspecies freudenreichii and shermanii. Ortholog grouping of the predicted protein sequences revealed that close to 86% of the ortholog groups of strain JS, including a variety of ripening-related ortholog groups, were conserved across the P. freudenreichii isolates. Taken together, this study contributes to the understanding of the genomic basis of P. freudenreichii and sheds light on its activities during cheese ripening.

      PubDate: 2016-10-14T15:35:30Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.022
      Issue No: Vol. 241 (2016)
  • Prevalence and antimicrobial resistance of Salmonella isolated from two
           pork processing plants in Alberta, Canada
    • Authors: Alma Fernanda Sanchez-Maldonado; Mueen Aslam; Cara Service; Claudia Narváez-Bravo; Brent P. Avery; Roger Johnson; Tineke H. Jones
      Pages: 49 - 59
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Alma Fernanda Sanchez-Maldonado, Mueen Aslam, Cara Service, Claudia Narváez-Bravo, Brent P. Avery, Roger Johnson, Tineke H. Jones
      This study investigated the frequency of Salmonella serovars on pig carcasses at various processing steps in two commercial pork processing plants in Alberta, Canada and characterized phenotypic and genotypic antimicrobial resistance (AMR) and PFGE patterns of the Salmonella isolates. Over a one year period, 1000 swab samples were collected from randomly selected pigs at two slaughter plants. Sampling points were: carcass swabs after bleeding (CSAB), carcass swabs after de-hairing (CSAD, plant A) or skinning (CSASk, plant B), carcass swabs after evisceration (CSAE), carcass swabs after pasteurization (CSAP, plant A) or washing (CSAW, plants B) and retail pork (RP). For plant A, 87% of CSAB and 8% of CSAE were positive for Salmonella while at plant B, Salmonella was recovered from 94% of CSAB and 10% of CSAE. Salmonella was not recovered from the RP samples at either plant, indicating that the plants used effective control measures. Salmonella enterica serovar Derby was the most common serotype (23%, 29/127) recovered in plant A and plant B (61%, 76/124). For plant A, 35% (45/127) of isolates were resistant to at least one antimicrobial. Five isolates (3.9%), 4 serovar Ohio strains and one serovar I:Rough-O:I,v:-, strain were simultaneously resistant to antimicrobials of very high (Category I), high (Category II), and medium (Category III) importance to human medicine. The 4 S. Ohio isolates were recovered from 3 different steps of pork processing on the same sampling day and displayed resistance to 5–7 antimicrobials, with all of them displaying resistance to ceftiofur and ceftriaxone (Category I). An I:Rough-O:l,v:- isolate, recovered on a different sampling day, was resistant to 7 antimicrobials that included resistance to ampicillin/clavulanic acid, ceftiofur and ceftriaxone (Category I). Salmonella strains isolated from plant A harbored 12 different AMR genes. The most prevalent genes were sul1, sul2, tet(A), tet(B), aadA, strA/strB, aac(3)IV and aphA1. For Salmonella isolates from plant B, 7 resistance genes were identified alone or in combination where tet(B) was found in 77 (62.3%) of the isolates. For plant A, 19 different PFGE subtypes of Salmonella isolates that displayed phenotypic and/or genotypic resistance were observed while 13 different PFGE subtypes were observed for plant B. The lack of detection of Salmonella on the surfaces of RP suggests that current pork processing practices can dramatically reduce Salmonella. Salmonella isolates from pig carcasses at various steps displayed multidrug resistance, including to those of very high importance in human medicine, which represent a public health concern.

      PubDate: 2016-10-14T15:35:30Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.004
      Issue No: Vol. 241 (2016)
  • Early transcriptional response to biotic stress in mixed starter
           fermentations involving Saccharomyces cerevisiae and Torulaspora
    • Authors: Jordi Tronchoni; Jose Antonio Curiel; Pilar Morales; Rafael Torres-Pérez; Ramon Gonzalez
      Pages: 60 - 68
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Jordi Tronchoni, Jose Antonio Curiel, Pilar Morales, Rafael Torres-Pérez, Ramon Gonzalez
      Advances in microbial wine biotechnology have led to the recent commercialization of several non-Saccharomyces starter cultures. These are intended to be used in either simultaneous or sequential inoculation with Saccharomyces cerevisiae. The different types of microbial interactions that can be stablished during wine fermentation acquire an increased relevance in the context of these mixed-starter fermentations. We analysed the transcriptional response to co-cultivation of S. cerevisiae and Torulaspora delbrueckii. The study focused in the initial stages of wine fermentation, before S. cerevisiae completely dominates the mixed cultures. Both species showed a clear response to the presence of each other, even though the portion of the genome showing altered transcription levels was relatively small. Changes in the transcription pattern suggested a stimulation of metabolic activity and growth, as a consequence of the presence of competitors in the same medium. The response of S. cerevisiae seems to take place earlier, as compared to T. delbrueckii. Enhanced glycolytic activity of the mixed culture was confirmed by the CO2 production profile during these early stages of fermentation. Interestingly, HSP12 expression appeared induced by co-cultivation for both of S. cerevisiae and Torulaspora delbrueckii in the two time points studied. This might be related with a recently described role of Hsp12 in intercellular communication in yeast. Expression of S. cerevisiae PAU genes was also stimulated in mixed cultures.

      PubDate: 2016-10-20T14:16:42Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.017
      Issue No: Vol. 241 (2016)
  • Improving simultaneously the quality and safety of cooked and peeled
           shrimp using a cocktail of bioprotective lactic acid bacteria
    • Authors: Taous Saraoui; Josiane Cornet; Emilie Guillouet; Marie France Pilet; Frédérique Chevalier; Jean-Jacques Joffraud; Françoise Leroi
      Pages: 69 - 77
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Taous Saraoui, Josiane Cornet, Emilie Guillouet, Marie France Pilet, Frédérique Chevalier, Jean-Jacques Joffraud, Françoise Leroi
      Tropical shrimp is of considerable economic importance in the world but is highly perishable due to microbial and chemical degradation. Biopreservation is a food preservation technology based on the addition of “positive” bacteria able to kill or prevent the growth of undesirable microorganisms. Two strains of lactic acid bacteria (LAB) have previously been selected for a biopreservation strategy: Lactococcus piscium CNCM I-4031, for its ability to prevent the sensory deterioration of seafood and Carnobacterium divergens V41, which inhibits growth of Listeria monocytogenes. The objective was to test the association of the two strains to improve both the quality and safety of shrimp. In a first trial, the two LAB were inoculated alone or in a cocktail in cooked and peeled shrimp (CPS) Penaeus vannamei at 5×105 CFU/g. Chemical, sensory and microbiological analyses by culture-dependent and -independent methods were performed during storage under modified atmosphere packaging (MAP) at 8°C. The results were compared to a non-inoculated batch. In a second trial, the same experiments were repeated in the presence of 102 CFU/g of L. monocytogenes RF191. The microbiota of CPS was composed of LAB, Shewanella spp. and Enterobacteriaceae. Brochothrix thermosphacta was not detected. L. piscium and C. divergens reached 108 and 109 CFU/g, respectively, in 7days and did not inhibit each other when co-inoculated. L. piscium reduced L. monocytogenes by 1Log (CFU/g) for 28days. C. divergens had an immediate listericidal effect lasting 7days. A regrowth of L. monocytogenes was then observed but the count was always 2 to 5Log (CFU/g) lower than in the control. No additional or synergic effect between protective strains was observed and the cocktail had the same inhibitory effect as C. divergens alone. C. divergens was very effective at preventing the sensory deterioration of CPS. This may be related to the inhibition of Shewanella and Enterobacteriaceae. However, the panelists could detect the presence of C. divergens during the first 10days of storage, with slight unpleasant odors and flavors. L. piscium improved the sensory quality of CPS for 14days only. In co-culture, L. piscium eliminated the off-odors and flavors released by C. divergens in the early stage of storage and the co-culture allowed maintaining a good quality of CPS throughout the storage. Therefore, the use of a cocktail of L. piscium CNCM I-4031 and C. divergens V41 is recommended in a strategy of biopreservation of shrimp.

      PubDate: 2016-10-20T14:16:42Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.024
      Issue No: Vol. 241 (2016)
  • Detection probability models for bacteria, and how to obtain them from
           heterogeneous spiking data. An application to Bacillus anthracis
    • Authors: Ronny Hedell; Olga Stephansson; Petter Mostad; Mats Gunnar Andersson
      Pages: 78 - 88
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Ronny Hedell, Olga Stephansson, Petter Mostad, Mats Gunnar Andersson
      Efficient and correct evaluation of sampling results with respect to hypotheses about the concentration or distribution of bacteria generally requires knowledge about the performance of the detection method. To assess the sensitivity of the detection method an experiment is usually performed where the target matrix is spiked (i.e. artificially contaminated) with different concentrations of the bacteria, followed by analyses of the samples using the pre-enrichment method and the analytical detection method of interest. For safety reasons or because of economic or time limits it is not always possible to perform exactly such an experiment, with the desired number of samples. In this paper, we show how heterogeneous data from diverse sources may be combined within a single model to obtain not only estimates of detection probabilities, but also, crucially, uncertainty estimates. We indicate how such results can then be used to obtain optimal conclusions about presence of bacteria, and illustrate how strongly the sampling results speak in favour of or against contamination. In our example, we consider the case when B. cereus is used as surrogate for B. anthracis, for safety reasons. The statistical modelling of the detection probabilities and of the growth characteristics of the bacteria types is based on data from four experiments where different matrices of food were spiked with B. anthracis or B. cereus and analysed using plate counts and qPCR. We show how flexible and complex Bayesian models, together with inference tools such as OpenBUGS, can be used to merge information about detection probability curves. Two different modelling approaches, differing in whether the pre-enrichment step and the PCR detection step are modelled separately or together, are applied. The relative importance on the detection curves for various existing data sets are evaluated and illustrated.

      PubDate: 2016-10-20T14:16:42Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.005
      Issue No: Vol. 241 (2016)
  • An AFLP based method for the detection and identification of indigenous
           yeast in complex must samples without a microbiological culture
    • Authors: Ignacio Baselga; Olga Zafra; Estela Pérez Lago; Raquel Francisco-Álvarez; Gemma Rodriguez-Tarduchy; Cruz Santos
      Pages: 89 - 97
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Ignacio Baselga, Olga Zafra, Estela Pérez Lago, Raquel Francisco-Álvarez, Gemma Rodriguez-Tarduchy, Cruz Santos
      Ribera de Duero Spanish wines are appreciated worldwide for their organoleptic characteristics; however, the wine market is very competitive, and the demand for high quality natural wines has been increasing in recent years. The microbiology of the process, specifically the yeasts involved in the alcoholic fermentation, constitutes an essential element directly related to the complexity and quality of the wine. Our work has focused on the development of a procedure to identify the indigenous wine yeasts present in complex samples of must and wine, without requiring colony isolation or a microbiological culture. The procedure is based on the use of AFLP molecular markers. The AFLP allele profiles obtained from complex samples are compared with the species-specific ones previously determined and included in a database using a sorting algorithm. The system allows a fast and efficient identification of yeast species and strains present in complex must and wine samples. This information can then be used by the enologists during the fermentation process in order to obtain signed wines.

      PubDate: 2016-10-20T14:16:42Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.014
      Issue No: Vol. 241 (2016)
  • Phenotyping and genetic characterization of Salmonella enterica isolates
           from Turkey revealing arise of different features specific to geography
    • Authors: Sinem Acar; Ece Bulut; Bora Durul; Ilhan Uner; Mehmet Kur; M. Dilek Avsaroglu; Hüseyin Avni Kirmaci; Yasar Osman Tel; Fadile Y. Zeyrek; Yesim Soyer
      Pages: 98 - 107
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Sinem Acar, Ece Bulut, Bora Durul, Ilhan Uner, Mehmet Kur, M. Dilek Avsaroglu, Hüseyin Avni Kirmaci, Yasar Osman Tel, Fadile Y. Zeyrek, Yesim Soyer
      192 Food samples (commonly consumed 8 food types), 355 animal samples (animal feces of bovine, ovine, goat and chicken) and 50 samples from clinical human cases in Sanliurfa city, Turkey in a year were collected to determine the Salmonella enterica subsp. enterica mosaic in Turkey. 161 Salmonella isolates represented 17 serotypes, 20 sequence types (STs) and 44 PFGE patterns (PTs). 3 serotypes, S. Enteritidis, S. Typhimurium and S. Kentucky, were recovered from three different hosts. The highest discriminatory power was obtained by PFGE (SID=0.945), followed by MLST (SID=0.902) and serotyping (SID=0.885) for all isolates. The prevalence of antimicrobial resistance genes (aadA1, aadA2, strA, strB, aphA 1-Iab , bla TEM-1 , bla PSE-1 , tetA) was highly correlated with phenotypic profiles of aminoglycoside, ß-lactam and tetracycline groups (kappa >0.85). From our knowledge, this is the first study reporting spatial and temporal distribution of Salmonella species through phenotypic and genetic approaches over farm to fork chain in Turkey. Thus, our data provided further information for evolution, ecology and transmission of Salmonella in Turkey.

      PubDate: 2016-10-20T14:16:42Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.031
      Issue No: Vol. 241 (2016)
  • Survey for the presence of ascaridoid larvae in the cinnamon flounder
           Pseudorhombus cinnamoneus (Temminck & Schlegel) (Pleuronectiformes:
    • Authors: Liang Li; Jin-Yu Zhao; Hui-Xia Chen; Hui-Dong Ju; Meng An; Zhen Xu; Lu-Ping Zhang
      Pages: 108 - 116
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Liang Li, Jin-Yu Zhao, Hui-Xia Chen, Hui-Dong Ju, Meng An, Zhen Xu, Lu-Ping Zhang
      The cinnamon flounder Pseudorhombus cinnamoneus is a frequently consumed marine fish in China. However, the occurrence of ascaridoid larvae in P. cinnamoneus remains unclear. In the present study, a total of 85 P. cinnamoneus caught from the Yellow Sea (off Shidao, 36°52′57″N, 122°26′42″E) in 2011, which is located between mainland China and the Korean Peninsula, was investigated for ascaridoid larval infection. Four ascaridoid larval types, including Anisakis type I of Berland (1961), Hysterothylacium type of Smith (1983), Hysterothylacium type HL of Guo et al. (2014) and Raphidascaris type of Zhao et al. (2016), were detected in this important food fish. These larval types were identified as Anisakis pegreffii, Hysterothylacium aduncum, H. sinense and Raphidascaris lophii, respectively, using PCR-based restriction fragment length polymorphism (PCR–RFLP) analysis and sequencing of the ITS region of nuclear ribosomal DNA (rDNA). The third-stage larvae of H. sinense are reported from Chinese waters for the first time. The prevalence of H. sinense was 100% and represents the predominant species of the ascaridoid larvae found in P. cinnamoneus. The prevalences of A. pegreffii and H. aduncum were 44.7% and 81.2%, respectively. Phylogenetic analyses based on ITS sequences were performed to elucidate the genetic relationships of these ascaridoid nematodes. The present study increases the knowledge and distribution of ascaridoid larvae in this area of Yellow Sea. The high prevalence of ascaridoid larvae in P. cinnamoneus shows that an assessment needs to be undertaken to assess the risk these parasites may pose to public health.

      PubDate: 2016-10-20T14:16:42Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.018
      Issue No: Vol. 241 (2016)
  • Fruit maturity and post-harvest environmental conditions influence the
           pre-penetration stages of Monilinia infections in peaches
    • Authors: C. Garcia-Benitez; P. Melgarejo; A. De Cal
      Pages: 117 - 122
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): C. Garcia-Benitez, P. Melgarejo, A. De Cal
      Brown rot caused by the fungi Monilinia laxa (Aderhold and Ruhland) Honey, M. fructicola (Winter) Honey, or M. fructigena (Aderhold and Ruhland) is a serious fungal disease of peaches. The fungal infection process begins when fungal conidia germinate on the fruit surface to produce germ tubes and/or appressoria, and the incidence of brown rot increases as fruit approaches maturity. The interaction between the fungal infection process, peach maturity, and the environmental conditions is not well understood. Accordingly, the objectives of this investigation were to investigate germ tube and appressorial formation by M. laxa and M. fructicola when they were exposed to peach skin from mature and immature fruit at various temperatures and relative humidities (RHs). The greatest number of germ tubes was found when M. laxa or M. fructicola was incubated in culture medium which contained a skin extract of mature peaches. In contrast, the greatest number of appressoria was found when M. laxa or M. fructicola was incubated in culture medium which contained a skin extract of immature peaches. Although M. fructicola produced the same number of germ tubes and appressoria at 4°C, M. fructicola produced more germ tubes than appressoria at temperatures higher than 10°C. M. laxa produced more germ tubes than appressoria at any temperature, except when it was incubated for 48h on culture medium which contained a skin extract of immature peaches at 10°C at 80% or 100% RH, or at 25°C at 60% RH. M. laxa conidia germinated better than M. fructicola conidia at low temperatures. Germ tube and appressorial formation by Monilinia spp. were influenced by fruit postharvest handling. The number of germ tubes that were formed by M. laxa conidia was significantly greater than that for M. fructicola when the conidia were incubated at 100% RH, and this number increased after 3days of refrigeration. The number of appressoria that were formed by both Monilinia spp. also increased after 3 consecutive days of refrigeration. Negligible or no germination of M. fructicola and M. laxa conidia occurred when the RH was 60%. We concluded that the dissimilar abilities of M. laxa and M. fructicola to germinate and form appressoria at low temperatures conferred a competitive advantage to M. laxa to survive during fruit postharvest refrigeration and cold storage at 4°C.

      PubDate: 2016-10-20T14:16:42Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.010
      Issue No: Vol. 241 (2016)
  • Activity of essential oil-based microemulsions against Staphylococcus
           aureus biofilms developed on stainless steel surface in different culture
           media and growth conditions
    • Authors: Campana Raffaella; Luca Casettari; Laura Fagioli; Marco Cespi; Giulia Bonacucina; Wally Baffone
      Pages: 132 - 140
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Campana Raffaella, Luca Casettari, Laura Fagioli, Marco Cespi, Giulia Bonacucina, Wally Baffone
      Food safety is a fundamental concern for both consumers and the food industry, especially as the numbers of reported cases of food-associated infections continue to increase. Industrial surfaces can provide a suitable substrate for the development and persistence of bacterial organized in biofilms that represent a potential source of food contamination. The negative consumer perception of chemical disinfectants has shifted the attention to natural substances, such as plant extracts. The aim of this study was to investigate the possibility of using the essential oils (EOs) in the fight against S. aureus biofilms. First, the Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), Minimum Biofilm Inhibitory Concentration (MBIC), Minimum Biofilm Eradication Concentration (MBEC) of eleven EOs against S. aureus were determined. Cinnamomum cassia and Salvia officinalis EOs showed the greatest antibacterial properties with 1.25% MIC and MBC, 1.25% MBIC and 2.5% MBEC respectively. Gas Chromatography/Mass Spectrometry analysis revealed cinnamaldehyde (82.66%) and methoxy cinnamaldehyde (10.12%) as the most abundant substances of C. cassia, while cis-thujone (23.90%), camphor (19.22%) and 1.8-cineole (10.62%) of S. officinalis. Three different microemulsions, formulated with C. cassia, S. officinalis or both, were finally tested against S. aureus biofilms in different culture media and growth conditions, causing a >3 logarithmic reductions in S. aureus 24h-old biofilms and desiccated biofilms, and up to 68% of biofilm removal after 90min of exposure. The obtained data suggest the potential use of EOs, alone or in combination, for the formulation of sanitizers as alternative or in support in the disinfection of contaminated surfaces.

      PubDate: 2016-10-20T14:16:42Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.021
      Issue No: Vol. 241 (2016)
  • Assessment of table olive fermentation by functional data analysis
    • Authors: M.A. Ruiz-Bellido; V. Romero-Gil; P. García-García; F. Rodríguez-Gómez; F.N. Arroyo-López; A. Garrido-Fernández
      Pages: 1 - 6
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): M.A. Ruiz-Bellido, V. Romero-Gil, P. García-García, F. Rodríguez-Gómez, F.N. Arroyo-López, A. Garrido-Fernández
      For the first time, functional data analysis (FDA) was used to assess the effects of different treatments on Protection Denomination of Origin Aloreña de Málaga table olive fermentations, focusing on the evolution of yeast population. The analysis of fermentation by a conventional approach led to scarce information. However, the transformation of microbial (and also physicochemical) data into smooth curves allowed the application of a new battery of statistical tools for the analysis of fermentations (functional pointwise estimation of the averages and standard deviations, maximum, minimum, first and second derivatives, functional regression, and functional F and t-tests). FDA showed that all the treatments assayed led to similar trends in yeast population while changes in pH and titratable acidity profiles led to several significant differences. Therefore, FDA represents a promising and valuable tool for studying table olive fermentations and for food microbiology in general.

      PubDate: 2016-08-31T14:03:07Z
      DOI: 10.1016/j.ijfoodmicro.2016.08.031
      Issue No: Vol. 238 (2016)
  • Development of synthetic media mimicking food soils to study the behaviour
           of Listeria monocytogenes on stainless steel surfaces
    • Authors: Anaïs Overney; Danielle Chassaing; Brigitte Carpentier; Laurent Guillier; Olivier Firmesse
      Pages: 7 - 14
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Anaïs Overney, Danielle Chassaing, Brigitte Carpentier, Laurent Guillier, Olivier Firmesse
      Listeria monocytogenes is one of the main targets of hygiene procedures in the ready-to-eat food industry due to its ability to persist for months or even years in processing plants, where it can contaminate food during processing. The factors associated with persistence are often those that foster growth, which itself depends on food contamination of surfaces. It is therefore essential to experiment by using food soils or media modelling these soils to understand the behaviour of L. monocytogenes on surfaces of food processing plants. Thus, we set up an experimental plan including three physiological parameters characteristic of the behaviour of cells on surfaces, namely spatial distribution, adhesion forces and the physiological state of sessile L. monocytogenes. These were recorded in two food soils: smoked salmon juice and meat exudate. According to our results, the behaviour of L. monocytogenes on stainless steel surfaces is highly dependent on the food soil used. The presence of viable but non-culturable (VBNC) cells was demonstrated using meat exudate, while all viable cells were recovered using smoked salmon juice. Moreover, on the basis of our criteria and after validation with three strains of L. monocytogenes, we showed that smoked salmon juice can be substituted by a modified culture medium, demonstrating that drawbacks associated with the use of food soils can be overcome.

      PubDate: 2016-08-31T14:03:07Z
      DOI: 10.1016/j.ijfoodmicro.2016.08.034
      Issue No: Vol. 238 (2016)
  • Fungal strains and the development of tolerance against natamycin
    • Authors: Hugo Streekstra; Alex E.E. Verkennis; Robbert Jacobs; Angelina Dekker; Jacques Stark; Jan Dijksterhuis
      Pages: 15 - 22
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Hugo Streekstra, Alex E.E. Verkennis, Robbert Jacobs, Angelina Dekker, Jacques Stark, Jan Dijksterhuis
      Antimicrobial resistance is a relevant theme with respect to both antibacterial and antifungal compounds. In this study we address the possible development of tolerance against the antifungal food preservative natamycin. A selection of 20 fungal species, originating from a medical as well as a food product context, was subjected to increasing concentrations of natamycin for prolonged time, a procedure designated as “training”. The range of Minimum Inhibitory Concentrations (M.I.C.) before (1.8–19.2μM) and after (1.8–19.8μM) training did not change significantly, but natamycin-exposure caused an increase of M.I.C. in 13 out of 20 tested strains. The average M.I.C. increased from 6.1 to 8.6μM and 4 strains showed a >2-fold increase of tolerance after training. One strain (of Aspergillus ochraceus) also showed increased tolerance to amphotericin B and nystatin. However, two Fusarium strains showed similar or even decreased tolerance for these other polyene antifungals. The work reported here shows that a continuous and prolonged increasing selection pressure induced natamycin tolerance in individual strains. This implies that such a selection pressure should be avoided in the technical application of natamycin to ensure its continued safe use as a food preservative.

      PubDate: 2016-08-31T14:03:07Z
      DOI: 10.1016/j.ijfoodmicro.2016.08.006
      Issue No: Vol. 238 (2016)
  • Inhibition of mycotoxin-producing fungi by Bacillus strains isolated from
           fish intestines
    • Authors: Flávio Fonseca Veras; Ana Paula Folmer Correa; Juliane Elisa Welke; Adriano Brandelli
      Pages: 23 - 32
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Flávio Fonseca Veras, Ana Paula Folmer Correa, Juliane Elisa Welke, Adriano Brandelli
      Bacillus strains isolated from the aquatic environment of the Brazilian Amazon region were tested for their activity against mycotoxigenic fungi. All tested bacteria showed antifungal activity, inhibiting at least 7 indicator fungi. Four Bacillus strains showing promising antifungal results were subsequently evaluated for their activity in reducing mycelial growth rate, sporulation, spore germination percentage, and mycotoxin production. Bacillus sp. P1 and Bacillus sp. P11 had a remarkable antifungal effect on toxigenic fungi. Washed bacterial cell suspension of strains P1 and P11 (107 CFU/ml) reduced by >70% the fungal colony diameters, including a complete inhibition of ochratoxin A (OTA) producing Aspergillus spp. Significant reduction of growth rate, sporulation and spore germination were also observed. The bacteria influenced the production of mycotoxins, causing a reduction around 99 and 97% in AFB1 and OTA concentration, respectively. Chromatographic analysis revealed the presence of lipopeptides (iturin A and surfactin isomers) in butanol extracts of cell-free supernatants and cell pellets of strains P1 and P11. Furthermore, antifungal activity of these extracts was confirmed against A. flavus A12 and A. carbonarius ITAL293, producers of AFB1 and OTA, respectively. These bacterial strains could be promising biocontrol agents against toxigenic fungi.

      PubDate: 2016-08-31T14:03:07Z
      DOI: 10.1016/j.ijfoodmicro.2016.08.035
      Issue No: Vol. 238 (2016)
  • In vitro activity of plant extracts against biofilm-producing food-related
    • Authors: Antonia Nostro; Alessandra Guerrini; Andreana Marino; Massimo Tacchini; Mara Di Giulio; Alessandro Grandini; Methap Akin; Luigina Cellini; Giuseppe Bisignano; Hatice T. Saraçoğlu
      Pages: 33 - 39
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Antonia Nostro, Alessandra Guerrini, Andreana Marino, Massimo Tacchini, Mara Di Giulio, Alessandro Grandini, Methap Akin, Luigina Cellini, Giuseppe Bisignano, Hatice T. Saraçoğlu
      The identification of effective antimicrobial agents also active on biofilms is a topic of crucial importance in food and industrial environment. For that purpose methanol extracts of Turkish plants, Ficus carica L., Juglans regia L., Olea europaea L., Punica granatum L. and Rhus coriaria L., were investigated. Among the extracts, P. granatum L. and R. coriaria L. showed the best antibacterial activity with minimum inhibitory concentrations (MIC) of 78–625μg/ml for Listeria monocytogenes and Staphylococcus aureus and 312–1250μg/ml for Escherichia coli and Pseudomonas aeruginosa. SubMICs produced a significant biofilm inhibition equal to 80–60% for L. monocytogenes and 90–80% for S. aureus. The extracts showed also the highest polyphenol content and the strongest antioxidant activity. Bioassay-guided and HPLC procedures demonstrated the presence of apigenin 4′-O-β-glucoside in P. granatum L. and myricetrin and quercitrin in R. coriaria L. Antigenotoxicity of plant extracts was also observed The present findings promote the value-adding of P. granatum L. and R. coriaria L. leaves as natural antimicrobial/antioxidant agents for control of food-related bacterial biofilms.

      PubDate: 2016-08-31T14:03:07Z
      DOI: 10.1016/j.ijfoodmicro.2016.08.024
      Issue No: Vol. 238 (2016)
  • Minimal processing of iceberg lettuce has no substantial influence on the
           survival, attachment and internalization of E. coli O157 and Salmonella
    • Authors: Inge Van der Linden; Karina R. Avalos Llano; Markus Eriksson; Winnok H. De Vos; Els J.M. Van Damme; Mieke Uyttendaele; Frank Devlieghere
      Pages: 40 - 49
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Inge Van der Linden, Karina R. Avalos Llano, Markus Eriksson, Winnok H. De Vos, Els J.M. Van Damme, Mieke Uyttendaele, Frank Devlieghere
      The influence of a selection of minimal processing techniques (sanitizing wash prior to packaging, modified atmosphere, storage conditions under light or in the dark) was investigated in relation to the survival of, attachment to and internalization of enteric pathogens in fresh produce. Cut Iceberg lettuce was chosen as a model for fresh produce, Escherichia coli O157:H7 (E. coli O157) and Salmonella enterica were chosen as pathogen models. Care was taken to simulate industrial post-harvest processing. A total of 50±0.1g of fresh-cut Iceberg lettuce was packed in bags under near ambient atmospheric air with approximately 21% O2 (NAA) conditions or equilibrium modified atmosphere with 3% O2 (EMAP). Two lettuce pieces inoculated with E. coli O157 BRMSID 188 or Salmonella Typhimurium labeled with green fluorescent protein (GFP) were added to each package. The bags with cut lettuce were stored under either dark or light conditions for 2days at 7°C. The pathogens' capacity to attach to the lettuce surface and cut edge was evaluated 2days after inoculation using conventional plating technique and the internalization of the bacteria was investigated and quantified using confocal microscopy. The effect of a sanitizing wash step (40mg/L NaClO or 40mg/L peracetic acid+1143mg/L lactic acid) of the cut lettuce prior to packaging was evaluated as well. Our results indicate that both pathogens behaved similarly under the investigated conditions. Pathogen growth was not observed, nor was there any substantial influence of the investigated atmospheric conditions or light/dark storage conditions on their attachment/internalization. The pathogens attached to and internalized via cut edges and wounds, from which they were able to penetrate into the parenchyma. Internalization through the stomata into the parenchyma was not observed, although some bacteria were found in the substomatal cavity. Washing the cut edges with sanitizing agents to reduce enteric pathogen numbers was not more effective than a rinse with precooled tap water prior to packaging. Our results confirm that cut surfaces are the main risk for postharvest attachment and internalization of E. coli O157 and Salmonella during minimal processing and that storage and packaging conditions have no important effect.

      PubDate: 2016-08-31T14:03:07Z
      DOI: 10.1016/j.ijfoodmicro.2016.07.029
      Issue No: Vol. 238 (2016)
  • Polymorphism and phylogenetic species delimitation in filamentous fungi
           from predominant mycobiota in withered grapes
    • Authors: M. Lorenzini; M.S. Cappello; A. Logrieco; G. Zapparoli
      Pages: 56 - 62
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): M. Lorenzini, M.S. Cappello, A. Logrieco, G. Zapparoli
      Filamentous fungi are the main pathogens of withered grapes destined for passito wine production. Knowledge of which species inhabit these post-harvest fruits and their pathogenicity is essential in order to develop strategies to control infection, but is still scarce. This study investigated the predominant mycobiota of withered grapes through a cultivation-dependent approach. Strain and species heterogeneity was evidenced on examining isolates collected over three consecutive years. Colony morphology and PCR-restriction fragment length polymorphism (PCR-RFLP) analysis revealed the occurrence of several phenotypes and haplotypes, respectively. Strains were phylogenetically analyzed based on sequence typing of different genes or regions (e.g. calmodulin, β-tubulin and internal transcribed spacer region). Beside the most common necrotrophic-saprophytic species of Penicillium, Aspergillus, Alternaria and Botrytis species responsible for fruit rot, other saprobic species were identified (e.g. Trichoderma atroviride, Sarocladium terricola, Arthrinium arundinis and Diaporthe eres) generally not associated with post-harvest fruit diseases. Species such as Penicillium ubiquetum, Cladosporium pseudocladosporioides, Lichtheimia ramosa, Sarocladium terricola, Diaporthe nobilis, Bipolaris secalis, Paraconiothyrium fuckelii and Galactomyces reessii that had never previously been isolated from grapevine or grape were also identified. Moreover, it was not possible to assign a species to some isolates, while some members of Didymosphaeriaceae and Didymellaceae remained unclassified even at genus level. This study provides insights into the diversity of the epiphytic fungi inhabiting withered grapes and evidences the importance of their identification to understand the causes of fruit diseases. Finally, phylogenetic species delimitation furnished data of interest to fungal taxonomy.

      PubDate: 2016-09-05T10:57:08Z
      DOI: 10.1016/j.ijfoodmicro.2016.08.039
      Issue No: Vol. 238 (2016)
  • Biofilm formation, phenotypic production of cellulose and gene expression
           in Salmonella enterica decrease under anaerobic conditions
    • Authors: A. Lamas; J.M. Miranda; B. Vázquez; A. Cepeda; C.M. Franco
      Pages: 63 - 67
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): A. Lamas, J.M. Miranda, B. Vázquez, A. Cepeda, C.M. Franco
      Salmonella enterica subsp. enterica is one of the main food-borne pathogens. This microorganism combines an aerobic life outside the host with an anaerobic life within the host. One of the main concerns related to S. enterica is biofilm formation and cellulose production. In this study, biofilm formation, morphotype, cellulose production and transcription of biofilm and quorum sensing-related genes of 11 S. enterica strains were tested under three different conditions: aerobiosis, microaerobiosis, and anaerobiosis. The results showed an influence of oxygen levels on biofilm production. Biofilm formation was significantly higher (P<0.05) in aerobiosis than in microaerobiosis and anaerobiosis. Cellulose production and RDAR (red, dry, and rough) were expressed only in aerobiosis. In microaerobiosis, the strains expressed the SAW (smooth and white) morphotype, while in anaerobiosis the colonies appeared small and red. The expression of genes involved in cellulose synthesis (csgD and adrA) and quorum sensing (sdiA and luxS) was reduced in microaerobiosis and anaerobiosis in all S. enterica strains tested. This gene expression levels were less reduced in S. Typhimurium and S. Enteritidis compared to the tested serotypes. There was a relationship between the expression of biofilm and quorum sensing-related genes. Thus, the results from this study indicate that biofilm formation and cellulose production are highly influenced by atmospheric conditions. This must be taken into account as contamination with these bacteria can occur during food processing under vacuum or modified atmospheres.

      PubDate: 2016-09-05T10:57:08Z
      DOI: 10.1016/j.ijfoodmicro.2016.08.043
      Issue No: Vol. 238 (2016)
  • Extended-spectrum β-lactamase producing Enterobacteriaceae in bulk tank
           milk from German dairy farms
    • Authors: Sabrina Odenthal; Ömer Akineden; Ewald Usleber
      Pages: 72 - 78
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Sabrina Odenthal, Ömer Akineden, Ewald Usleber
      Although the dairy farm environment is a known source of extended-spectrum β-lactamase (ESBL)-producing bacteria, surveillance data on ESBL in the milk production chain are still scarce. This study aimed at estimating the dimensions of the problem for public health and animal welfare by surveying ESBL-producing Enterobacteriaceae in raw bulk tank milk in Germany. Samples from 866 dairy farms, comprising about 1% of the total number of dairy farms in Germany, were first screened for presence of cefotaxime-resistant bacteria by selective enrichment. Suspect colonies were identified phenotypically and further characterized by biochemical and molecular methods, including analysis of resistance genes and clonal diversity in ESBL-producing isolates. Bulk tank milk from 82 (9.5%) farms yielded Enterobacteriaceae with confirmed ESBL-production. The most frequent ESBL-producing species was Escherichia coli (75.6%), followed by Citrobacter spp. (9.6%), Enterobacter cloacae (6.1%), and Klebsiella oxytoca (3.7%), a few isolates belonged to other species within the genera Hafnia, Raoutella and Serratia. The majority of isolates (95.1%) harbored the β-lactamase blaCTX-M gene, which has gained increased importance among ESBL-producing strains worldwide; the CTX-M group 1 was found to be the dominating (88.4%) phylogenetic group. All ESBL-positive Escherichia coli isolates were clonally heterogeneous, as determined by pulsed-field gel electrophoresis. The results from this survey demonstrate that ESBL-producing bacteria are distributed widely in the dairy farm environment in Germany. Therefore, raw milk is a potential source of exposure for the consumer, which is of increasing importance considering the trend of farmer-to-consumer direct marketing. Furthermore, dairy farm staff have an increased likelihood of exposure to ESBL-producing bacteria. Finally, ESBL-producing bacteria may also be transferred via waste milk to calves, thus further spreading antibiotic resistance in the farm environment.

      PubDate: 2016-09-05T10:57:08Z
      DOI: 10.1016/j.ijfoodmicro.2016.08.036
      Issue No: Vol. 238 (2016)
  • Comparative morphological characteristics of three Brettanomyces
           bruxellensis wine strains in the presence/absence of sulfur dioxide
    • Authors: Marli Louw; Maret du Toit; Hervé Alexandre; Benoit Divol
      Pages: 79 - 88
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Marli Louw, Maret du Toit, Hervé Alexandre, Benoit Divol
      The red wine spoilage yeast Brettanomyces bruxellensis has been the subject of numerous investigations. Some of these studies focused on spoilage mechanisms, sulfur dioxide tolerance and nutrient requirements. Pseudomycelium formation, although a striking feature of this species, has however been poorly investigated. Furthermore, literature regarding the induction mechanism of pseudomycelium formation in this yeast is limited and lacks clarity, as results published are contradictory. This study elucidates this phenomenon among strains from geographically different areas. Potential environmental cues were investigated, to attain a better understanding of this mechanism and its role as a survival strategy. SO2 was previously reported to induce this morphological change however results obtained in this study did not support this. Nevertheless, the results obtained using scanning and transmission electron microscopy illustrate, for the first time in this yeast, deformity to the cell membrane and alterations to the fibrillar layers in SO2 treated cells. In addition, the SO2 exposed cultures displayed cell size variations, with cells displaying a decrease in length as well as delayed growth, with a prolonged lag phase. Fluorescence microscopy demonstrated a decrease in metabolic activity and the appearance of inclusion body-like structures in the cells following exposure to SO2.

      PubDate: 2016-09-05T10:57:08Z
      DOI: 10.1016/j.ijfoodmicro.2016.08.040
      Issue No: Vol. 238 (2016)
  • Virulence factors and antimicrobial resistance in Escherichia coli strains
           isolated from hen egg shells
    • Authors: María José Grande Burgos; Maria Luisa Fernández Márquez; Rubén Pérez Pulido; Antonio Gálvez; Rosario Lucas López
      Pages: 89 - 95
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): María José Grande Burgos, Maria Luisa Fernández Márquez, Rubén Pérez Pulido, Antonio Gálvez, Rosario Lucas López
      Eggs may contain extraintestinal pathogenic (ExPEC) and diarrheogenic (DEC) Escherichia coli which in addition may carry antibiotic resistance. The wide use of biocides and disinfectants in the food industry may induce biocide tolerance in bacteria. The aim of the present study was to evaluate biocide tolerance and antibiotic resistance in E. coli from hen egg shells. A total of 27 isolates obtained from a screening of 180 eggs were studied. Seven isolates carried both eae and bfpA genes of typical enteropathogenic E. coli (EPEC) strains, while 14 isolates only carried eae associated with atypical EPEC strains. Shiga toxin genes stx and stx2 were detected in four isolates. Heat-stable and heat-labile enterotoxin genes as well as aggR were also detected. Several isolates had minimum inhibitory concentrations (MICs) that were higher than the wild-type for the biocide hexadecylpyridinium chloride (HDP, 18.52%) or the commercial disinfectant P3 oxonia (OX, 14.81%). Antibiotic resistance was detected for ampicillin (37.03%), streptomycin (37.03%), tetracycline (37.03%), chloramphenicol (11.11%), nalidixic acid (18.51%) and trimethoprim-sulfamethoxazole (14.81%). Eight isolates (29.63%) were biocide tolerant and antibiotic resistant. Efflux pump genes detected included acrB (96.29%), mdfA (85.18%) and oxqA (37.03%), in addition to quaternary ammonium compound (QAC) resistance genes qacA/B (11.11%) and qacE (7.40%). Antibiotic resistance genes detected included bla CTX-M-2 (22.22%), bla TEM (3.70%), bla PSE (3.70%), tet(A) (29.63%), tet(B) (29.63%), tet(C) (7.40%), tet(E) (11.11%), aac(6′)-Ib (3.70%), sul1 (14.81%), dfrA12 (3.70%) and dfrA15 (3.70%). Most isolates (96.30%) carried more than one genetic determinant of resistance. The most frequent combinations were efflux pump components acrB and mdfA with tetracycline resistance genes (33.33% of isolates). Isolates carrying QAC resistance genes also carried between 4 and 8 of the additional antimicrobial resistance genes investigated. Regardless of biocide tolerance and antibiotic resistance, all isolates were sensitive to carvacrol (0.25%), thymol (0.125%) and trisodium phosphate (1 to 1.5%), but they exhibited a heterogeneous response to sodium lactate and lysozyme-EDTA combinations that apparently were not related with antibiotic resistance. Results from the study reveal not only a low incidence of biocide tolerance but also the presence of multiple resistance strains carrying multiple genetic determinants of resistance.

      PubDate: 2016-09-11T11:00:56Z
      DOI: 10.1016/j.ijfoodmicro.2016.08.037
      Issue No: Vol. 238 (2016)
  • Comparative proteomic analyses for elucidating metabolic changes during
           EPS production under different fermentation temperatures by Lactobacillus
           plantarum Q823
    • Authors: Esteban Vera Pingitore; Alessandro Pessione; Cecilia Fontana; Roberto Mazzoli; Enrica Pessione
      Pages: 96 - 102
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Esteban Vera Pingitore, Alessandro Pessione, Cecilia Fontana, Roberto Mazzoli, Enrica Pessione
      Exopolysaccharide (EPS)-producing bacteria are of growing interest in industrial processes, mainly concerning food. Lactic acid bacteria are widely appreciated for their GRAS (generally recognized as safe) status and their ascertained or putative probiotic features. Detailed investigation on what happens at metabolic level during EPS production is scarce in the literature. The facultative heterofermenter Lactobacillus plantarum Q823 was studied in order to compare growth and EPS production at 30°C and 37°C. A higher growth rate was observed at 37°C, whereas, a significantly higher (tenfold increase) EPS amount was produced at 30°C. To understand the molecular mechanisms leading to the different EPS production in the two conditions, a comparative proteomic experiment was performed. The results of the in-gel proteomics revealed that: i) at 37°C a higher abundance of proteins involved in carbon catabolism and nucleic acid biosynthesis together with a significant amount of stress proteins was observed; ii) at 30°C the production of an atypical manganese-containing non-heme catalase (pseudocatalase) was increased, in agreement with previous data reporting that growth-rates of catalase negative Lactobacillus plantarum strains were greater than that of catalase positive strains. Taken together, all these findings provide further insights about the metabolic pathways stimulated during EPS production, and the mechanism that triggers EPS biosynthesis.

      PubDate: 2016-09-11T11:00:56Z
      DOI: 10.1016/j.ijfoodmicro.2016.08.010
      Issue No: Vol. 238 (2016)
  • Fermentation of African kale (Brassica carinata) using L. plantarum BFE
           5092 and L. fermentum BFE 6620 starter strains
    • Authors: Folarin A. Oguntoyinbo; Gyu-Sung Cho; Bernhard Trierweiler; Jan Kabisch; Niels Rösch; Horst Neve; Wilhelm Bockelmann; Lara Frommherz; Dennis S. Nielsen; Lukasz Krych; Charles M.A.P. Franz
      Pages: 103 - 112
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Folarin A. Oguntoyinbo, Gyu-Sung Cho, Bernhard Trierweiler, Jan Kabisch, Niels Rösch, Horst Neve, Wilhelm Bockelmann, Lara Frommherz, Dennis S. Nielsen, Lukasz Krych, Charles M.A.P. Franz
      Vegetables produced in Africa are sources of much needed micronutrients and fermentation is one way to enhance the shelf life of these perishable products. To prevent post-harvest losses and preserve African leafy vegetables, Lactobacillus plantarum BFE 5092 and Lactobacillus fermentum BFE 6620 starter strains were investigated for their application in fermentation of African kale (Brassica carinata) leaves. They were inoculated at 1×107 cfu/ml and grew to a maximum level of 108 cfu/ml during 24h submerged fermentation. The strains utilized simple sugars (i.e., glucose, fructose, and sucrose) in the kale to quickly reduce the pH from pH6.0 to pH3.6 within 24h. The strains continued to produce both d and l lactic acid up to 144h, reaching a maximum concentration of 4.0g/l. Fermentations with pathogens inoculated at 104 cfu/ml showed that the quick growth of the starters inhibited the growth of Listeria monocytogenes and Salmonella Enteritidis, as well as other enterobacteria. Denaturing gradient gel electrophoresis and 16S rRNA gene (V3-V4-region) amplicon sequencing showed that in the spontaneous fermentations a microbial succession took place, though with marked differences in biodiversity from fermentation to fermentation. The fermentations inoculated with starters however were clearly dominated by both the inoculated strains throughout the fermentations. RAPD-PCR fingerprinting showed that the strains established themselves at approx. equal proportions. Although vitamins C, B1 and B2 decreased during the fermentation, the final level of vitamin C in the product was an appreciable concentration of 35mg/100g. In conclusion, controlled fermentation of kale offers a promising avenue to prevent spoilage and improve the shelf life and safety.

      PubDate: 2016-09-11T11:00:56Z
      DOI: 10.1016/j.ijfoodmicro.2016.08.030
      Issue No: Vol. 238 (2016)
  • Staphylococci isolated from ready-to-eat meat – Identification,
           antibiotic resistance and toxin gene profile
    • Authors: Karol Fijałkowski; Dorota Peitler; Jolanta Karakulska
      Pages: 113 - 120
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Karol Fijałkowski, Dorota Peitler, Jolanta Karakulska
      The aim of this study was to analyse the staphylococci isolated from ready-to-eat meat products, including pork ham, chicken cold cuts, pork sausage, salami and pork luncheon meat, sliced in the store to the consumer's specifications, along with species identification and determination of antibiotic resistance. Genes encoding staphylococcal enterotoxins, staphylococcal enterotoxin-like proteins, exfoliative toxins, and toxic shock syndrome toxin 1 were also investigated. From the 41 samples, 75 different staphylococcal isolates were obtained. Based on PCR-RFLP analysis of the gap gene using AluI and HpyCH4V restriction enzymes, the isolates were identified as Staphylococcus equorum (28%), S. vitulinus (16%), S. carnosus (14%), S. succinus (11%), S. xylosus (11%), S. saprophyticus (9%), S. warneri (9%), S. haemolyticus (1%) and S. pasteuri (1%). The incidence and number of resistances to antimicrobials was found to be species but not source of isolation dependent. All S. xylosus, S. saprophyticus, S. haemolyticus and S. pasteuri isolates showed antibiotic resistance. A lower percentage of resistance was recorded for S. warneri (71%) and S. vitulinus (58%), followed by S. equorum (57%), S. carnosus (50%) and S. succinus (50%). The most frequent resistance was observed to fusidic acid (43%). The mecA gene was amplified in 4% of the staphylococci. However, phenotypic resistance to methicillin was not confirmed in any of these isolates. On the other hand, the mecA gene was not detected in any of 9% of the isolates resistant to cefoxitin. It was also found that among 75 isolates, 60 (80%) harbored from 1 to 10 out of 21 analyzed superantigenic toxin genes. The most prevalent genes were: sei (36% isolates) among enterotoxins, seln (32% isolates) among enterotoxin-like proteins and eta encoding exfoliative toxin A (37% isolates). The findings of this study further extend previous observations that, when present in food, not only S. aureus but also other species of staphylococci could be of public health significance.

      PubDate: 2016-09-11T11:00:56Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.001
      Issue No: Vol. 238 (2016)
  • Distribution of tannin-'tolerant yeasts isolated from Miang, a traditional
    • Authors: Apinun Kanpiengjai; Naradorn Chui-Chai; Siriporn Chaikaew; Chartchai Khanongnuch
      Pages: 121 - 131
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Apinun Kanpiengjai, Naradorn Chui-Chai, Siriporn Chaikaew, Chartchai Khanongnuch
      Miang is a fermented food product prepared from the tea leaves of Camellia sinensis var. assamica, and is traditionally produced in mountainous areas of northern Thailand. Although Miang has a long history and reveals deep-rooted cultural involvement with local people in northern Thailand, little is known regarding its microbial diversity. Yeasts were isolated from 47 Miang samples collected from 28 sampling sites, including eight provinces in upper northern Thailand. A hundred and seven yeast isolates were recovered and identified within 14 species based on the comparison of the D1/D2 sequence of the large subunit (LSU) rRNA gene. Candida ethanolica was determined to be the dominant species that was frequently found in Miang together with minor resident yeast species. All yeast isolates demonstrated their tannin-tolerant capability when cultivated on yeast malt agar (YMA) containing 50g/l tannin, but nine isolates displayed clear zones forming around their colonies, e.g., Debaryomyces hansenii, Cyberlindnera rhodanensis, and Sporidiobolus ruineniae. The results obtained from a visual reading method of tannase revealed that all yeast isolates were positive for methyl gallate, indicating that they possess tannase activity. It is assumed that a tannin-tolerant ability is one of the most important factors for developing a yeast community in Miang. This research study is the first report to describe tannin-tolerant yeasts and yeast communities in traditionally fermented tea leaves.

      PubDate: 2016-09-11T11:00:56Z
      DOI: 10.1016/j.ijfoodmicro.2016.08.044
      Issue No: Vol. 238 (2016)
  • Characteristics of Vibrio parahaemolyticus isolates obtained from crayfish
           (Procambarus clarkii) in freshwater
    • Authors: Xingxing Dong; Zhi Li; Xiaohong Wang; Min Zhou; Li Lin; Yang Zhou; Jinquan Li
      Pages: 132 - 138
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Xingxing Dong, Zhi Li, Xiaohong Wang, Min Zhou, Li Lin, Yang Zhou, Jinquan Li
      Vibrio parahaemolyticus usually occurs in coastal areas and is generally recognized as a marine bacterium. It has become the leading cause of gastroenteritis worldwide. In the present study, 96 V. parahaemolyticus isolates were obtained from freshwater crayfish (Procambarus clarkii) and classified by multilocus sequence typing. Fifty-three sequence types (STs) were identified among the 96 isolates analyzed, 38 of which were novel STs. These isolates fell into six groups and 42 singletons, suggesting a high level of genetic diversity. Screening for 9 virulence and virulence-related genes in the isolates revealed that 40 isolates contained more than two genes with possible roles in pathogenicity. The virulence of the representative isolates VP66 (trh +, ureC +, T3SS1+, T3SS2β+, T6SS2+) and VP80 (T3SS1+, T6SS1+, T6SS2+) were further assessed in zebrafish and mouse infection model in vivo, and the tested isolates were shown to be lethal to both zebrafish and mice. These results suggest that crayfish may serve as a carrier of V. parahaemolyticus in freshwater, and that some isolates may have the potential to cause foodborne disease in humans.

      PubDate: 2016-09-11T11:00:56Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.004
      Issue No: Vol. 238 (2016)
  • Effect of sodium alginate coating incorporated with nisin, Cinnamomum
           zeylanicum, and rosemary essential oils on microbial quality of chicken
           meat and fate of Listeria monocytogenes during refrigeration
    • Authors: Mojtaba Raeisi; Alijan Tabaraei; Mohammad Hashemi; Nasser Behnampour
      Pages: 139 - 145
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Mojtaba Raeisi, Alijan Tabaraei, Mohammad Hashemi, Nasser Behnampour
      The present study was conducted to preserve the microbial quality of chicken meat fillets during storage time by using sodium alginate active coating solutions incorporated with different natural antimicrobials including nisin, Cinnamomum zeylanicum (cinnamon), and rosemary essential oils (EOs) which were added individually and in combination. The samples were stored in refrigeration condition for 15days and were analyzed for total viable count, Enterobacteriaceae count, lactic acid bacteria count, Pseudomonas spp. count, psychrotrophic count, and yeast and mold count, as well as fate of inoculated Listeria monocytogenes at 3-day intervals. Results indicated that values of tested microbial indicators in all samples increased during storage. Antimicrobial agents, when used in combination, had stronger effect in preserving the microbial quality of chicken meat samples rather than their individual use and the strongest effect was observed in samples coated with alginate solution containing both cinnamon and rosemary EOs (CEO+REO). However, all treatments significantly inhibited microbial growth when compared to the control (P <0.05). Therefore, based on the results of this study, application of alginate coating solutions containing nisin, cinnamon, and rosemary EOs as natural preservatives is recommended in meat products especially in chicken meats.

      PubDate: 2016-09-11T11:00:56Z
      DOI: 10.1016/j.ijfoodmicro.2016.08.042
      Issue No: Vol. 238 (2016)
  • Is staphylococci population from milk of healthy goats safe'
    • Authors: Patricia Ruiz; Iris Barragán; Susana Seseña; María Llanos Palop
      Pages: 146 - 152
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Patricia Ruiz, Iris Barragán, Susana Seseña, María Llanos Palop
      The aim of this study was to assess the species and the genetic diversity of the staphylococci population in raw milk from healthy goats. Isolates representative of all genotypes were screened for their potential pathogenicity by the occurrence of some relevant safety-related properties, such as antibiotic resistance, presence of virulence factor genes, biofilm formation ability and biogenic amine production. A total of 314 staphylococci were isolated, and randomly amplified polymorphic DNA-PCR analysis displayed 48 genotypes. Isolates were identified as belonging to S. epidermidis (87.5%), S. caprae (6.2%), S. aureus (4.2%) and S. simulans (2.1%) species. The antibiotic resistance varied strongly with strains, with S. epidermidis and S. aureus strains showing resistance to more number of antibiotics. A high occurrence of strains harbouring hemolysin genes was also found in both species. On the contrary, none of the strains assayed harboured enterotoxin or amino acid decarboxylase genes, and, although a moderate or high biofilm formation was observed in 29% of the strains, they did not harbour icaA or icaD genes. This study gives a first and extensive picture of safety-related properties within Staphylococcus species isolated from milk of healthy goats, displaying that these species can act as a reservoir for spreading genes related to safety.

      PubDate: 2016-09-11T11:00:56Z
      DOI: 10.1016/j.ijfoodmicro.2016.08.033
      Issue No: Vol. 238 (2016)
  • LaeA and VeA are involved in growth morphology, asexual development, and
           mycotoxin production in Alternaria alternata
    • Authors: N. Estiarte; C.B. Lawrence; V. Sanchis; A.J. Ramos; A. Crespo-Sempere
      Pages: 153 - 164
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): N. Estiarte, C.B. Lawrence, V. Sanchis, A.J. Ramos, A. Crespo-Sempere
      Alternaria alternata is a common filamentous fungus that contaminates various fruits, grains and vegetables causing important economic losses to farmers and the food industry. A. alternata is a mycotoxigenic mould, which may jeopardize human and animal health. Two of the most common A. alternata mycotoxins found in food and feed are alternariol and alternariol monomethyl ether. In this study we examined the role of LaeA and VeA, two regulatory proteins belonging to the velvet family, which have been described to be involved in several functions in many fungi including secondary metabolism. We found that deletion of laeA and veA genes, respectively, greatly reduced sporulation and strongly compromised mycotoxin production, both in vitro or during pathogenesis of tomato fruits. We have also studied how the loss of laeA and veA may affect expression of genes related to alternariol and alternariol monomethyl ether biosynthesis (pksJ and altR), and to melanin biosynthesis (cmrA, pksA).

      PubDate: 2016-09-20T18:18:15Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.003
      Issue No: Vol. 238 (2016)
  • Inhibition of Staphylococcus aureus by antimicrobial biofilms formed by
           competitive exclusion microorganisms on stainless steel
    • Authors: Hyeri Son; Sunhyung Park; Larry R. Beuchat; Hoikyung Kim; Jee-Hoon Ryu
      Pages: 165 - 171
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Hyeri Son, Sunhyung Park, Larry R. Beuchat, Hoikyung Kim, Jee-Hoon Ryu
      The goal of this study was to develop a desiccation resistant antimicrobial surface using biofilm of competitive exclusion (CE) microorganism inhibitory to Staphylococcus aureus. We isolated 161 microorganisms from soils, foods, and food-contact surfaces that are inhibitory to S. aureus. Among them, three CE microorganisms (Streptomyces spororaveus strain Gaeunsan-18, Bacillus safensis strain Chamnamu-sup 5–25, and Pseudomonas azotoformans strain Lettuce-9) exhibiting strong antibacterial activity and high growth rates were selected for evaluation. These isolates formed biofilms within 24h on stainless steel coupons (SSCs) immersed in Bennet's broth and tryptic soy broth at 25°C. Cells in these biofilms showed significantly (P ≤0.05) enhanced resistance to a desiccation (43% relative humidity [RH]) compared to those attached to SSCs but not in biofilms. The antimicrobial activities of biofilms formed by these isolates on SSCs against S. aureus at 25°C and 43% RH were determined. Compared to SSCs lacking biofilms formed by CE microorganisms, populations of S. aureus on SSCs harboring CE biofilms were significantly lower (P ≤0.05). Results indicate that persistent antimicrobial activity against S. aureus on stainless steel surfaces can be achieved by the presence of biofilms of CE microorganisms. This information will be useful when developing strategies to improve the microbiological safety of foods during storage, processing, and distribution by facilitating the development of effective antimicrobial food-contact surfaces.

      PubDate: 2016-09-20T18:18:15Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.007
      Issue No: Vol. 238 (2016)
  • Chemical, physical and morphological properties of bacterial biofilms
           affect survival of encased Campylobacter jejuni F38011 under aerobic
    • Authors: Jinsong Feng; Guillaume Lamour; Rui Xue; Mehr Negar Mirvakliki; Savvas G. Hatzikiriakos; Jie Xu; Hongbin Li; Shuo Wang; Xiaonan Lu
      Pages: 172 - 182
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Jinsong Feng, Guillaume Lamour, Rui Xue, Mehr Negar Mirvakliki, Savvas G. Hatzikiriakos, Jie Xu, Hongbin Li, Shuo Wang, Xiaonan Lu
      Campylobacter jejuni is a microaerophilic pathogen and leading cause of human gastroenteritis. The presence of C. jejuni encased in biofilms found in meat and poultry processing facilities may be the major strategy for its survival and dissemination in aerobic environment. In this study, Staphylococcus aureus, Salmonella enterica, or Pseudomonas aeruginosa was mixed with C. jejuni F38011 as a culture to form dual-species biofilms. After 4days' exposure to aerobic stress, no viable C. jejuni cells could be detected from mono-species C. jejuni biofilm. In contrast, at least 4.7logCFU/cm2 of viable C. jejuni cells existed in some dual-species biofilms. To elucidate the mechanism of protection mode, chemical, physical and morphological features of biofilms were characterized. Dual-species biofilms contained a higher level of extracellular polymeric substances with a more diversified chemical composition, especially for polysaccharides and proteins, than mono-species C. jejuni biofilm. Structure of dual-species biofilms was more compact and their surface was >8 times smoother than mono-species C. jejuni biofilm, as indicated by atomic force microscopy. Under desiccation stress, water content of dual-species biofilms decreased slowly and remained at higher levels for a longer time than mono-species C. jejuni biofilm. The surface of all biofilms was hydrophilic, but total surface energy of dual-species biofilms (ranging from 52.5 to 56.2mJ/m2) was lower than that of mono-species C. jejuni biofilm, leading to more resistance to wetting by polar liquids. This knowledge can aid in developing intervention strategies to decrease the survival and dispersal of C. jejuni into foods or environment.

      PubDate: 2016-09-20T18:18:15Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.008
      Issue No: Vol. 238 (2016)
  • The efficacy of Mentha arvensis L. and M. piperita L. essential oils in
           reducing pathogenic bacteria and maintaining quality characteristics in
           cashew, guava, mango, and pineapple juices
    • Authors: Jossana Pereira de Sousa Guedes; José Alberto da Costa Medeiros; Richard Sidney de Souza e Silva; Janaína Maria Batista de Sousa; Maria Lúcia da Conceição; Evandro Leite de Souza
      Pages: 183 - 192
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Jossana Pereira de Sousa Guedes, José Alberto da Costa Medeiros, Richard Sidney de Souza e Silva, Janaína Maria Batista de Sousa, Maria Lúcia da Conceição, Evandro Leite de Souza
      This study evaluated the ability of the essential oil from Mentha arvensis L. (MAEO) and M. piperita L. (MPEO) to induce ≥5-log reductions in counts (CFU/mL) of E. coli, L. monocytogenes, and Salmonella enterica serovar Enteritidis in Brain-Heart Infusion broth (BHIB) and cashew, guava, mango, and pineapple juices during refrigerated storage (4±0.5°C). The effects of the incorporation of these essential oils on some physicochemical and sensory parameters of juices were also evaluated. The incorporation of 5, 2.5, 1.25, or 0.625μL/mL of MAEO in BHIB caused a ≥5-log reduction in counts of E. coli and Salmonella Enteritidis after 24h of storage; but only 5μL/mL was able to cause the same reduction in counts of L. monocytogenes. The incorporation of 10μL/mL of MPEO in BHIB caused a ≥5-log reduction in counts of E. coli, Salmonella Enteritidis, and L. monocytogenes after 24h of storage; smaller reductions were observed in BHIB containing 5, 2.5, and 1.25μL/mL of MPEO. Similar reductions were observed when the MAEO or MPEO was incorporated at the same concentrations in mango juice. The incorporation of MAEO or MPEO at all tested concentrations in cashew, guava, and pineapple juices resulted in a ≥5-log reduction in pathogen counts within 1h. The incorporation of MAEO and MPEO (0.625 and 1.25μL/mL, respectively) in fruit juices did not induce alterations in °Brix, pH, and acidity, but negatively affected the taste, aftertaste, and overall acceptance. The use of MAEO or MPEO at low concentrations could constitute an interesting tool to achieve the required 5-log reduction of pathogenic bacteria in cashew, guava, mango, and pineapple fruit juices. However, new methods combining the use of MAEO or MPEO with other technologies are necessary to reduce their negative impacts on specific sensory properties of these juices.

      PubDate: 2016-09-20T18:18:15Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.005
      Issue No: Vol. 238 (2016)
  • The heat resistance and spoilage potential of aerobic mesophilic and
           thermophilic spore forming bacteria isolated from Chinese milk powders
    • Authors: Faizan A. Sadiq; Yun Li; TongJie Liu; Steve Flint; Guohua Zhang; Lei Yuan; Zhipeng Pei; GuoQing He
      Pages: 193 - 201
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Faizan A. Sadiq, Yun Li, TongJie Liu, Steve Flint, Guohua Zhang, Lei Yuan, Zhipeng Pei, GuoQing He
      The propensity for aerobic bacilli and allied genera to produce highly heat-resistant spores and thermally stable spoilage enzymes are major bacteriological issues faced by the dairy industry. Most of the enzymes are able to survive any heat treatment applied during the manufacture of milk powders and have the potential to remain active in milk powders and other dairy products during storage, and may explain some of the sensory and functionality defects reported in dairy products. Despite many reports on the occurrence of spore-forming bacteria in dairy products, knowledge about food quality related properties of many aerobic sporeformers is still scarce. Therefore, the aim of this study was to determine thermal resistance and spoilage potential of a large pool of mesophilic and thermophilic sporeformers, representing 738 isolates and 31 different RAPD groups, recently isolated from Chinese milk powders. Spore formers producing highly heat resistant spores (surviving 125°C for 30min) included 2 thermophiles (Geobacillus thermoleovorans group and Geobacillus stearothermophilus) and one mesophilic species (Brevibacillus brevis). Paenibacillus macerans showed the highest proteolytic activity followed by members of the Bacillus cereus group, Br. brevis, Bacillus subtilis, G. thermoleovorans group and Virgibacillus proomii. The highest lipase producing strains belonged to Bacillus licheniformis. Phospholipase activity was only shown by members of the B. cereus group and Brevibacillus parabrevis. Ten strains showed positive β-galactosidase activity, while, 4 strains showed positive haemolytic activity. B. licheniformis strains, despite belonging to one RAPD group or sub-group showed markedly different phenotypic characters which support the previous findings of heterogeneity in RAPD-based B. licheniformis groups. The results of this study will broaden the knowledge about the spoilage potential and thermal resistance of many strains of dairy origin.

      PubDate: 2016-09-20T18:18:15Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.009
      Issue No: Vol. 238 (2016)
  • Microbial dynamics of indicator microorganisms on fresh tomatoes in the
           supply chain from Mexico to the USA
    • Authors: Claire Zoellner; Fabiola Venegas; John J. Churey; Jorge Dávila-Aviña; Yrjo T. Grohn; Santos García; Norma Heredia; Randy W. Worobo
      Pages: 202 - 207
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Claire Zoellner, Fabiola Venegas, John J. Churey, Jorge Dávila-Aviña, Yrjo T. Grohn, Santos García, Norma Heredia, Randy W. Worobo
      Quality and safety of fresh produce are important to public health and maintaining commerce between Mexico and USA. While preventive practices can reduce risks of contamination and are generally successful, the variable environment of the supply chain of fresh produce can be suitable for introduction or proliferation of pathogenic microorganisms. As routine surveillance of these pathogens is not practical, indicator microorganisms are used to assess the sanitary conditions of production and handling environments. An opportunity exists to use indicators on fresh produce to measure how handling and transport from field to market may affect microbial populations that contribute to their quality or safety. The objective was to quantify indicator microorganisms on tomatoes sampled along the supply chain during the harvest year, in order to observe the levels and changes of populations at different locations. Roma tomatoes (n=475) were taken from the same lots (n=28) at four locations of the postharvest supply chain over five months: at arrival to and departure from the packinghouse in México, at the distribution center in Texas, and at retail in USA. Samples were analyzed individually for four microbial populations: aerobic plate count (APC), total coliforms (TC), generic Escherichia coli, and yeasts and molds (YM). APC population differed (p<0.05) from 1.9±1.1, 1.7±1.1, 2.3±1.1 and 3.5±1.4logCFU/g at postharvest, packing, distribution center and supermarket, respectively. TC populations were <1logCFU/g at postharvest, increased at packing (0.7±1.0logCFU/g), decreased in distribution (0.4±0.8logCFU/g) and increased in supermarkets (1.4±1.5logCFU/g). Generic E. coli was not identified from coliform populations in this supply chain. YM populations remained <1logCFU/g, with the exception of 1.1±1.3logCFU/g at supermarkets and tomatoes were not visibly spoiled. The levels reported from this pilot study demonstrated the dynamics within populations as influenced by time and conditions in one supply chain during a harvest year, while the large variances in some locations indicate opportunities for improvement. Overall, packinghouse and supermarket locations were identified as crucial points to control microbial safety risks.

      PubDate: 2016-09-24T18:22:35Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.013
      Issue No: Vol. 238 (2016)
  • Antimicrobial effects of vinegar against norovirus and Escherichia coli in
           the traditional Korean vinegared green laver (Enteromorpha intestinalis)
           salad during refrigerated storage
    • Authors: Shin Young Park; Sujin Kang; Sang-Do Ha
      Pages: 208 - 214
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Shin Young Park, Sujin Kang, Sang-Do Ha
      In Korea, edible seaweeds are potentially regarded as high-risk foods with respect to enteric norovirus (NoV) and non-pathogenic generic Escherichia coli. This study investigated the antimicrobial effects of 5%, 10%, and 15% vinegar (6% acetic acid) on the survival of murine norovirus-1 (MNV-1), a human NoV surrogate, and E. coli, a fecal indicator in experimentally contaminated raw fresh green lavers (Enteromorpha intestinalis) during a 7-d storage period at 4°C. Both MNV-1 titers and E. coli counts significantly (p<0.05) decreased with stepwise increase in vinegar concentration and storage time, except in E. coli of the 0% vinegar-containing lavers; however, MNV-1 was more resistant to vinegar than E. coli. The overall average MNV-1 titers were significantly (p<0.05) higher in 0% vinegar-containing lavers (3.6log10PFU/ml) than in 5–15% vinegar-containing lavers (3.3–3.1log10PFU/ml) throughout the 7days of storage. A 1-log reduction in the MNV-1 titer was observed in 0% vinegar-containing laver samples after 5days of storage and 5–15% vinegar-containing laver samples after 3days of storage. The overall E. coli count was also significantly (p<0.05) decreased in the 15% (6.8log10CFU/g) vinegar-containing lavers than in the 10% (7.3log10CFU/g) and 5% (7.6log10CFU/g) vinegar-containing lavers. A >1-log reduction in the E. coli count was observed in 10–15% vinegar-containing laver samples just after 1day of storage. A 2-log reduction in the E. coli count was also observed in 10–15% vinegar-containing laver samples after 5days of storage. Using the non-linear Weibull model, this study showed that the dR-values (1-log reduction) of MNV-1 were 4.90days for 0%, 4.28days for 5%, 3.79days for 10%, and 2.88days for 15% vinegar-containing lavers, whereas those for E. coli were 1.12day for 5%, 1.03day for 10%, and 0.90day for 15% vinegar-containing lavers stored at 4°C. Vinegar with over the storage time can be used as an antimicrobial ingredient against NoV and E. coli in Korean conventional foods. Specifically, this study suggests that ~1day of storage is required for 1-log reduction in the E. coli count in the vinegar-containing (5–15%) lavers, whereas 3–5days of storage at 4°C is adequate for 1-log reduction in the MNV-1 count in the vinegar-containing and non-vinegar-containing lavers.

      PubDate: 2016-09-24T18:22:35Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.002
      Issue No: Vol. 238 (2016)
  • Oligosaccharides containing an α-(1→2) (glucosyl/xylosyl)-fructosyl
           linkage as inducer molecules of trichothecene biosynthesis for Fusarium
    • Authors: Yuichi Nakajima; Kazuyuki Maeda; Qi Jin; Naoko Takahashi-Ando; Kyoko Kanamaru; Tetsuo Kobayashi; Makoto Kimura
      Pages: 215 - 221
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Yuichi Nakajima, Kazuyuki Maeda, Qi Jin, Naoko Takahashi-Ando, Kyoko Kanamaru, Tetsuo Kobayashi, Makoto Kimura
      Fructo-oligosaccharides containing a sucrose unit are reported as carbon sources necessary for trichothecene production by Fusarium graminearum. Here we demonstrate that trichothecene production is induced when at least 100μM sucrose is added to a culture medium containing 333mM glucose in a 24-well plate. When glucose, the main carbon source of the medium, was replaced with galactose, maltose, or sorbitol, the addition of 100μM sucrose could no longer induce trichothecene production. However, replacing half the amount of each carbon source with glucose restored the trichothecene production-inducing activity of sucrose. Detailed investigations with media containing various concentrations of galactose and glucose as carbon sources suggested that operation of the galactose catabolic pathway for energy conservation affected trichothecene biosynthesis induction by sucrose. Trichothecene production was also induced by 100μM of either raffinose or xylosucrose in axenic liquid culture medium containing glucose as the major carbon source. These results demonstrate that sucrose derivatives are not necessary as a carbon source for inducing trichothecene biosynthesis, and that the minimum structural requirement for sugars to function as trichothecene production-inducer molecules is to contain an α-(1→2) (glucosyl/xylosyl)-fructosyl linkage.

      PubDate: 2016-09-24T18:22:35Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.011
      Issue No: Vol. 238 (2016)
  • Plasma inactivation of microorganisms on sprout seeds in a dielectric
           barrier discharge
    • Authors: Denis Butscher; Hanne Van Loon; Alexandra Waskow; Philipp Rudolf von Rohr; Markus Schuppler
      Pages: 222 - 232
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Denis Butscher, Hanne Van Loon, Alexandra Waskow, Philipp Rudolf von Rohr, Markus Schuppler
      Fresh produce is frequently contaminated by microorganisms, which may lead to spoilage or even pose a threat to human health. In particular sprouts are considered to be among the most risky foods sold at retail since they are grown in an environment practically ideal for growth of bacteria and usually consumed raw. Because heat treatment has a detrimental effect on the germination abilities of sprout seeds, alternative treatment technologies need to be developed for microbial inactivation purposes. In this study, non-thermal plasma decontamination of sprout seeds is evaluated as a promising option to enhance food safety while maintaining the seed germination capabilities. In detail, investigations focus on understanding the efficiency of non-thermal plasma inactivation of microorganisms as influenced by the type of microbial contamination, substrate surface properties and moisture content, as well as variations in the power input to the plasma device. To evaluate the impact of these parameters, we studied the reduction of native microbiota or artificially applied E. coli on alfalfa, onion, radish and cress seeds exposed to non-thermal plasma in an atmospheric pressure pulsed dielectric barrier discharge streamed with argon. Plasma treatment resulted in a maximum reduction of 3.4 logarithmic units for E. coli on cress seeds. A major challenge in plasma decontamination of granular food products turned out to be the complex surface topology, where the rough surface with cracks and crevices can shield microorganisms from plasma-generated reactive species, thus reducing the treatment efficiency. However, improvement of the inactivation efficiency was possible by optimizing substrate characteristics such as the moisture level and by tuning the power supply settings (voltage, frequency) to increase the production of reactive species. While the germination ability of alfalfa seeds was considerably decreased by harsh plasma treatment, enhanced germination was observed under mild conditions. In conclusion, the results from this study indicate that cold plasma treatment represents a promising technology for inactivation of bacteria on seeds used for sprout production while preserving their germination properties.

      PubDate: 2016-09-24T18:22:35Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.006
      Issue No: Vol. 238 (2016)
  • Isolation of baker's yeast mutants with proline accumulation that showed
           enhanced tolerance to baking-associated stresses
    • Authors: Ariunzaya Tsolmonbaatar; Keisuke Hashida; Yukiko Sugimoto; Daisuke Watanabe; Shuhei Furukawa; Hiroshi Takagi
      Pages: 233 - 240
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Ariunzaya Tsolmonbaatar, Keisuke Hashida, Yukiko Sugimoto, Daisuke Watanabe, Shuhei Furukawa, Hiroshi Takagi
      During bread-making processes, yeast cells are exposed to baking-associated stresses such as freeze-thaw, air-drying, and high-sucrose concentrations. Previously, we reported that self-cloning diploid baker's yeast strains that accumulate proline retained higher-level fermentation abilities in both frozen and sweet doughs than the wild-type strain. Although self-cloning yeasts do not have to be treated as genetically modified yeasts, the conventional methods for breeding baker's yeasts are more acceptable to consumers than the use of self-cloning yeasts. In this study, we isolated mutants resistant to the proline analogue azetidine-2-carboxylate (AZC) derived from diploid baker's yeast of Saccharomyces cerevisiae. Some of the mutants accumulated a greater amount of intracellular proline, and among them, 5 mutants showed higher cell viability than that observed in the parent wild-type strain under freezing or high-sucrose stress conditions. Two of them carried novel mutations in the PRO1 gene encoding the Pro247Ser or Glu415Lys variant of γ-glutamyl kinase (GK), which is a key enzyme in proline biosynthesis in S. cerevisiae. Interestingly, we found that these mutations resulted in AZC resistance of yeast cells and desensitization to proline feedback inhibition of GK, leading to intracellular proline accumulation. Moreover, baker's yeast cells expressing the PRO1 P247S and PRO1 E415K gene were more tolerant to freezing stress than cells expressing the wild-type PRO1 gene. The approach described here could be a practical method for the breeding of proline-accumulating baker's yeasts with higher tolerance to baking-associated stresses.

      PubDate: 2016-09-24T18:22:35Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.015
      Issue No: Vol. 238 (2016)
  • New insights into the mechanisms of acetic acid resistance in Acetobacter
           pasteurianus using iTRAQ-dependent quantitative proteomic analysis
    • Authors: Kai Xia; Ning Zang; Junmei Zhang; Hong Zhang; Yudong Li; Ye Liu; Wei Feng; Xinle Liang
      Pages: 241 - 251
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Kai Xia, Ning Zang, Junmei Zhang, Hong Zhang, Yudong Li, Ye Liu, Wei Feng, Xinle Liang
      Acetobacter pasteurianus is the main starter in rice vinegar manufacturing due to its remarkable abilities to resist and produce acetic acid. Although several mechanisms of acetic acid resistance have been proposed and only a few effector proteins have been identified, a comprehensive depiction of the biological processes involved in acetic acid resistance is needed. In this study, iTRAQ-based quantitative proteomic analysis was adopted to investigate the whole proteome of different acidic titers (3.6, 7.1 and 9.3%, w/v) of Acetobacter pasteurianus Ab3 during the vinegar fermentation process. Consequently, 1386 proteins, including 318 differentially expressed proteins (p <0.05), were identified. Compared to that in the low titer circumstance, cells conducted distinct biological processes under high acetic acid stress, where >150 proteins were differentially expressed. Specifically, proteins involved in amino acid metabolic processes and fatty acid biosynthesis were differentially expressed, which may contribute to the acetic acid resistance of Acetobacter. Transcription factors, two component systems and toxin-antitoxin systems were implicated in the modulatory network at multiple levels. In addition, the identification of proteins involved in redox homeostasis, protein metabolism, and the cell envelope suggested that the whole cellular system is mobilized in response to acid stress. These findings provide a differential proteomic profile of acetic acid resistance in Acetobacter pasteurianus and have potential application to highly acidic rice vinegar manufacturing.

      PubDate: 2016-10-01T04:28:43Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.016
      Issue No: Vol. 238 (2016)
  • Molecular characterization of Toxoplasma gondii in pork meat from
           different production systems in the Czech Republic
    • Authors: Michal Slany; Nikol Reslova; Vladimir Babak; Alena Lorencova
      Pages: 252 - 255
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Michal Slany, Nikol Reslova, Vladimir Babak, Alena Lorencova
      Toxoplasmosis is a major public health issue, due to the presence of Toxoplasma gondii, mainly in pork. The aim of this study was to determine the occurrence of T. gondii in pigs and wild boars bred in different production systems in the Czech Republic using ELISA and qPCR methods. Our results show that T. gondii infection is widespread in pigs and wild boars bred and slaughtered in the Czech Republic and that there is a higher exposure to T. gondii in backyard slaughter operations and organic pig farming, indicating a potential risk for meat consumption. Additionally, genotyping of amplified loci for Type II suggests the presence of one clonal genotype circulating in these animals.

      PubDate: 2016-10-01T04:28:43Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.020
      Issue No: Vol. 238 (2016)
  • Inactivation efficiency and mechanism of UV-TiO2 photocatalysis against
           murine norovirus using a solidified agar matrix
    • Authors: Daseul Park; Hafiz Muhammad Shahbaz; Sun-Hyoung Kim; Mijin Lee; Wooseong Lee; Jong-Won Oh; Dong-Un Lee; Jiyong Park
      Pages: 256 - 264
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Daseul Park, Hafiz Muhammad Shahbaz, Sun-Hyoung Kim, Mijin Lee, Wooseong Lee, Jong-Won Oh, Dong-Un Lee, Jiyong Park
      Human norovirus (HuNoV) is the primary cause of viral gastroenteritis worldwide. Fresh blueberries are among high risk foods associated with norovirus related outbreaks. Therefore, it is important to assess intervention strategies to reduce the risk of foodborne illness. The disinfection efficiency of decontamination methods is difficult to evaluate for fruits and vegetables due to an inconsistent degree of contamination and irregular surface characteristics. The inactivation efficiency and mechanism of murine norovirus 1 (MNV-1, a surrogate for HuNoV) was studied on an experimentally prepared solidified agar matrix (SAM) to simulate blueberries using different wavelengths (A, B, C) of UV light both with and without TiO2 photocatalysis (TP). MNV-1 was inoculated on exterior and interior of SAM and inactivation efficiencies of different treatments were investigated using a number of assays. Initial inoculum levels of MNV-1 on the SAM surface and interior were 5.2logPFU/mL. UVC with TiO2 (UVC-TP) achieved the highest level of viral reduction for both externally inoculated and internalized MNV-1. Externally inoculated MNV-1 was reduced to non-detectable levels after UVC-TP treatment for 5min while there was still a 0.9 log viral titer after UVC alone. For internalized MNV-1, 3.2 log and 2.7 log reductions were obtained with UVC-TP and UVC alone treatments for 10min, respectively. The Weibull model was applied to describe the inactivation behavior of MNV-1, and the model showed a good fit to the data. An excellent correlation between the steady-state concentration of OH radicals ([OH]ss) and viral inactivation was quantified using a para–chlorobenzoic acid (pCBA) probe compound, suggesting that OH radicals produced in the UV-TP reaction were the major species for MNV-1 inactivation. Transmission electron microscopy images showed that the structure of viral particles was completely disrupted with UVC-TP and UVC alone. SDS-PAGE analysis showed that the major capsid protein VP1 was degraded after UVC-TP and UVC alone. Real-time RT-qPCR analysis showed that UVC-TP and UVC alone caused a reduction in the level of viral genomic RNA. Propidium monoazide (PMA) pretreatment RT-qPCR analysis showed that UVC-TP caused damage to the viral capsid protein in addition to viral genomic RNA. UVC both with and without TiO2 was more effective for MNV-1 inactivation than UVB and UVA. Thus, UVC-TP disinfection aimed to reduce levels of food-borne viruses can inactivate viruses present on the surface and internalized in the interior of blueberries.

      PubDate: 2016-10-07T12:02:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.025
      Issue No: Vol. 238 (2016)
  • Highlighting the microbial diversity of 12 French cheese varieties
    • Authors: Eric Dugat-Bony; Lucille Garnier; Jeremie Denonfoux; Stéphanie Ferreira; Anne-Sophie Sarthou; Pascal Bonnarme; Françoise Irlinger
      Pages: 265 - 273
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Eric Dugat-Bony, Lucille Garnier, Jeremie Denonfoux, Stéphanie Ferreira, Anne-Sophie Sarthou, Pascal Bonnarme, Françoise Irlinger
      Surface-ripened cheeses host complex microbial communities responsible for the transformation of milk into cheese as well as the development of important properties in terms of texture, color and sensory perception. In this study, we used high-throughput amplicon sequencing to decipher the bacterial and fungal diversity of 60 cheeses belonging to 12 popular French cheese varieties. Using this approach, 76 bacterial and 44 fungal phylotypes were identified. Major differences were observed between rind and core samples and also according to cheese varieties and manufacturing processes. Occurrence analysis revealed the presence of widespread taxa as well as operational taxonomic units (OTUs) specific to one or several cheese varieties. Finally, we observed patterns specific to the cheese production facility, supporting the importance of indigenous microorganisms for the microbial assemblage of cheese microbiota.

      PubDate: 2016-10-07T12:02:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.026
      Issue No: Vol. 238 (2016)
  • Characterization of nonpathogenic Listeria species isolated from food and
           food processing environment
    • Authors: Dorota Korsak; Magdalena Szuplewska
      Pages: 274 - 280
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Dorota Korsak, Magdalena Szuplewska
      A total of 127 Listeria isolates from food and food processing environments, including 75 L. innocua, 49 L. welshimeri, 2 L. seeligeri and 1 L. grayi were tested for susceptibility to eight antimicrobials, benzalkonium chloride (BC), cadmium and arsenic. The isolates were also screened for the presence of extrachromosomal genetic elements - plasmids, and their restriction pattern types were determined. All strains were susceptible to ampicillin, ciprofloxacin, erythromycin, gentamicin, rifampicin, trimethoprim and vancomycin. Two of the L. innocua isolates showed resistance to tetracycline and minocycline. The resistance was determined by the presence of chromosomal localization of tet(M) gene, which was not integrated in the transposon Tn916-Tn1545 family. Of analyzed isolates, 18.11% and 55.91% isolates were resistant to BC and cadmium, respectively, but all were susceptible to arsenic. Resistance to BC was correlated with resistance to cadmium - all BC resistant isolates were also resistant to cadmium. On the other hand, 67.61% of cadmium-resistant isolates were susceptible to BC, suggesting that cadmium and BC resistance were not always concurrent in Listeria species. 48.03% of isolates contained plasmids. The size of most of the identified replicons was in the range of 50–90kb. All plasmids were classified into 12 groups with identical restriction pattern (I–XII). Interestingly, plasmids belonging to the same group were determined in isolates of the same species. Only in one case, plasmids with I-type profile were identified in L. innocua and L. welshimeri. There was an association between resistance to BC and plasmid DNA presence: all resistant isolates carried a plasmid. A correlation between resistance to cadmium and plasmid carriage was also observed in L. innocua and L. seeligeri isolates, but among resistant L. welshimeri, 23.08% of isolates did not have plasmids. This may suggest that resistance is associated with determinants located within the chromosome. To elucidate the adaptation strategies and ecology of Listeria spp., it is important to have a better understanding of its resistance to antimicrobials and environmental toxicants such as heavy metals and disinfectants.

      PubDate: 2016-10-07T12:02:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.08.032
      Issue No: Vol. 238 (2016)
  • Applicability of the EN ISO 11290-1 standard method for Listeria
           monocytogenes detection in presence of new Listeria species
    • Authors: Léna Barre; Apostolos S. Angelidis; Djouher Boussaid; Emilie Decourseulles Brasseur; Eléonore Manso; Nathalie Gnanou Besse
      Pages: 281 - 287
      Abstract: Publication date: 5 December 2016
      Source:International Journal of Food Microbiology, Volume 238
      Author(s): Léna Barre, Apostolos S. Angelidis, Djouher Boussaid, Emilie Decourseulles Brasseur, Eléonore Manso, Nathalie Gnanou Besse
      During the past six years, new species of the genus Listeria have been isolated from foods and other environmental niches worldwide. The Standard method EN ISO 11290-1 that is currently under revision will include in its scope all Listeria species in addition to L. monocytogenes. The objective of this project was to evaluate the ability of the Standard EN ISO 11290-1 method to detect and identify the newly discovered Listeria spp., and to assess potential over-growth effects of the new species in mixed cultures with L. monocytogenes during each step of the enrichment process. This objective was addressed by the generation of necessary data on the behavior of the new species during the pre-enrichment and the enrichment steps of the reference method as well as data on their phenotypic characteristics on rich and selective media used for isolation and identification. Most of the new Listeria species developed well on selective agar media for Listeria, however the recovery of some species was difficult due to poor growth in Half Fraser and Fraser broth. Good results (consistently positive) were obtained for confirmation at the genus level via the catalase test, the Gram test and the blueish appearance test on non-selective medium, but not with the VP test, as most of the new species yielded a negative result. In the light of results obtained in co-culture experiments and inhibition tests, and considering the growth rates in Half Fraser and Fraser broths, the new species do not seem to interfere with the detection of L. monocytogenes.

      PubDate: 2016-10-07T12:02:20Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.028
      Issue No: Vol. 238 (2016)
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