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MICROBIOLOGY (240 journals)                  1 2     

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

        1 2     

Journal Cover International Journal of Food Microbiology
  [SJR: 1.614]   [H-I: 121]   [12 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0168-1605
   Published by Elsevier Homepage  [2817 journals]
  • Inhibition of biofilm development and spoilage potential of Shewanella
           baltica by quorum sensing signal in cell-free supernatant from Pseudomonas
    • Abstract: Publication date: 2 August 2016
      Source:International Journal of Food Microbiology, Volume 230
      Author(s): Aifei Zhao, Junli Zhu, Xiaofeng Ye, Yangyang Ge, Jianrong Li
      The objective of this study was to in vitro evaluate the effect of a cell-free supernatant (CFS) containing quorum sensing (QS) signal of Pseudomonas fluorescens on the growth, biofilm development and spoilage potential of Shewanella baltica, and preliminarily assess the interactive influences of various chemically synthesized autoinducers on spoilage phenotypes of S. baltica. PF01 strain isolated from spoiled Pseudosciaen crocea was identified P. fluorescens. The addition of 25% and 50% CFS to S. baltica culture had no effect on the growth rate during the lag and exponential phase, however, caused cell decline during the stationary phase. The presence of CFS from P. fluorescens significantly inhibited biofilm development, and greatly decreased the production of trimethylamine (TMA) and biogenic amino in S. baltica. Various signal molecules of QS in the CFS of P. fluorescens culture were detected, including seven N-acyl-l-homoserine lactones (AHLs), autoinducer-2 (AI-2) and two diketopiperazines (DKPs). Exogenous supplement of synthesized seven AHLs containing in the CFS decreased biofilm formation and TMA production in S. baltica, while exposure to exogenous cyclo-(l-Pro-l-Leu) was showed to promote spoilage potential, which revealed that S. baltica also sense the two QS molecules. Furthermore, the stimulating effect of cyclo-(l-Pro-l-Leu) was affected when AHL was simultaneously added, suggesting that the inhibitory activity of spoilage phenotypes in S. baltica might be attributed to a competitive effect of these QS compounds in the CFS of P. fluorescens. The present studies provide a good basis for future research on the role of QS in the regulation of spoilage microbial flora.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

      PubDate: 2016-04-07T13:02:18Z
  • ICFMH Announcment
    • Abstract: Publication date: 2 June 2016
      Source:International Journal of Food Microbiology, Volume 226

      PubDate: 2016-04-07T13:02:18Z
  • Editorial Board
    • Abstract: Publication date: 2 June 2016
      Source:International Journal of Food Microbiology, Volume 226

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

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

      PubDate: 2016-04-03T13:02:07Z
  • Editorial Board
    • Abstract: Publication date: 16 May 2016
      Source:International Journal of Food Microbiology, Volume 225

      PubDate: 2016-04-03T13:02:07Z
  • Tracing isolates from domestic human Campylobacter jejuni infections to
           chicken slaughter batches and swimming water using whole-genome multilocus
           sequence typing
    • Abstract: Publication date: 2 June 2016
      Source:International Journal of Food Microbiology, Volume 226
      Author(s): Sara Kovanen, Rauni Kivistö, Ann-Katrin Llarena, Ji Zhang, Ulla-Maija Kärkkäinen, Tamara Tuuminen, Jaakko Uksila, Marjaana Hakkinen, Mirko Rossi, Marja-Liisa Hänninen
      Campylobacter jejuni is the leading cause of bacterial gastroenteritis and chicken is considered a major reservoir and source of human campylobacteriosis. In this study, we investigated temporally related Finnish human (n=95), chicken (n=83) and swimming water (n=20) C. jejuni isolates collected during the seasonal peak in 2012 using multilocus sequence typing (MLST) and whole-genome MLST (wgMLST). Our objective was to trace domestic human C. jejuni infections to C. jejuni isolates from chicken slaughter batches and swimming water. At MLST level, 79% of the sequence types (STs) of the human isolates overlapped with chicken STs suggesting chicken as an important reservoir. Four STs, the ST-45, ST-230, ST-267 and ST-677, covered 75% of the human and 64% of the chicken isolates. In addition, 50% of the swimming water isolates comprised ST-45, ST-230 and ST-677. Further wgMLST analysis of the isolates within STs, accounting their temporal relationship, revealed that 22 of the human isolates (24%) were traceable back to C. jejuni positive chicken slaughter batches. None of the human isolates were traced back to swimming water, which was rather sporadically sampled. The highly discriminatory wgMLST, together with the patient background information and temporal relationship data with possible sources, offers a new, accurate approach to trace back the origin of domestic campylobacteriosis. Our results suggest that potentially a substantial proportion of campylobacteriosis cases during the seasonal peak most probably are due to other sources than chicken meat consumption. These findings warrant further wgMLST-based studies to reassess the role of other reservoirs in the Campylobacter epidemiology both in Finland and elsewhere.

      PubDate: 2016-04-03T13:02:07Z
  • Getting insight into the prevalence of antibiotic resistance genes in
           specimens of marketed edible insects
    • Abstract: Publication date: 16 June 2016
      Source:International Journal of Food Microbiology, Volume 227
      Author(s): Vesna Milanović, Andrea Osimani, Marina Pasquini, Lucia Aquilanti, Cristiana Garofalo, Manuela Taccari, Federica Cardinali, Paola Riolo, Francesca Clementi
      This study was aimed at investigating the occurrence of 11 transferable antibiotic resistance (AR) genes [erm(A), erm(B), erm(C), vanA, vanB, tet(M), tet(O), tet(S), tet(K), mecA, blaZ] in 11 species of marketed edible insects (small crickets powder, small crickets, locusts, mealworm larvae, giant waterbugs, black ants, winged termite alates, rhino beetles, mole crickets, silkworm pupae, and black scorpions) in order to provide a first baseline for risk assessment. Among the AR genes under study, tet(K) occurred with the highest frequency, followed by erm(B), tet(S) and blaZ. A high variability was seen among the samples, in terms of occurrence of different AR determinants. Cluster Analysis and Principal Coordinates Analysis allowed the 11 samples to be grouped in two main clusters, one including all but one samples produced in Thailand and the other including those produced in the Netherlands.

      PubDate: 2016-04-03T13:02:07Z
  • A revised method of examining fish for infection with zoonotic nematode
    • Abstract: Publication date: 16 June 2016
      Source:International Journal of Food Microbiology, Volume 227
      Author(s): Shokoofeh Shamsi, Jaydipbhai Suthar
      The infection of fish with zoonotic nematodes, particularly anisakid nematodes is of great interest to many researchers who study food safety, human or animal health or who use them as biological tags for stock assessment studies. Accurate examination of fish for infection with anisakid larvae is crucial in making accurate estimates of their occurrence, abundance and prevalence in their fish hosts. Here we describe a new method of examining fish for infection with these parasites. In 2015, a total of 261 fish were purchased from a fish market in New South Wales, Australia. All fish were first examined by routine visual examination for infection with zoonotic nematode larvae and all data were recorded. Subsequently all internal organs were placed in a container and filled with water and incubated in the room temperature overnight. The prevalence, mean intensity and mean abundance of anisakids were significantly higher (p <0.05) when the revised method of examination, i.e., combining visual examination and overnight incubation in room temperature, was employed (63.98, 8.23 and 5.27, respectively) compared to routine visual examination with or without the aid of a microscope (8.81, 3.78 and 0.33, respectively). The proposed method is effective and has several advantages, such as: not using UV or HCl for fish examination, allowing the examination of a larger number of fish in shorter time; larval specimens collected being suitable for both morphological and DNA sequencing; and being simple and inexpensive. The disadvantages would be the odour of the specimens after overnight incubation as well as not being suitable for use with frozen fish. We suggest that results, conclusions or recommendations made in studies that claim no anisakid/ascaridoid larvae were found in a fish should be approached carefully if it is only based on visual examination of the fish.

      PubDate: 2016-04-03T13:02:07Z
  • Transcriptome analysis of Lactococcus lactis subsp. lactis during milk
           acidification as affected by dissolved oxygen and the redox potential
    • Abstract: Publication date: 2 June 2016
      Source:International Journal of Food Microbiology, Volume 226
      Author(s): Nadja Larsen, Saloomeh Moslehi-Jenabian, Birgit Brøsted Werner, Maiken Lund Jensen, Christel Garrigues, Finn Kvist Vogensen, Lene Jespersen
      Performance of Lactococcus lactis as a starter culture in dairy fermentations depends on the levels of dissolved oxygen and the redox state of milk. In this study the microarray analysis was used to investigate the global gene expression of L. lactis subsp. lactis DSM20481T during milk acidification as affected by oxygen depletion and the decrease of redox potential. Fermentations were carried out at different initial levels of dissolved oxygen (dO2) obtained by milk sparging with oxygen (high dO2, 63%) or nitrogen (low dO2, 6%). Bacterial exposure to high initial oxygen resulted in overexpression of genes involved in detoxification of reactive oxygen species (ROS), oxidation–reduction processes, biosynthesis of trehalose and down-regulation of genes involved in purine nucleotide biosynthesis, indicating that several factors, among them trehalose and GTP, were implicated in bacterial adaptation to oxidative stress. Generally, transcriptional changes were more pronounced during fermentation of oxygen sparged milk. Genes up-regulated in response to oxygen depletion were implicated in biosynthesis and transport of pyrimidine nucleotides, branched chain amino acids and in arginine catabolic pathways; whereas genes involved in salvage of nucleotides and cysteine pathways were repressed. Expression pattern of genes involved in pyruvate metabolism indicated shifts towards mixed acid fermentation after oxygen depletion with production of specific end-products, depending on milk treatment. Differential expression of genes, involved in amino acid and pyruvate pathways, suggested that initial oxygen might influence the release of flavor compounds and, thereby, flavor development in dairy fermentations. The knowledge of molecular responses involved in adaptation of L. lactis to the shifts of redox state and pH during milk fermentations is important for the dairy industry to ensure better control of cheese production.

      PubDate: 2016-03-30T13:00:47Z
  • Characterization of thermophilic fungal community associated with pile
           fermentation of Pu-erh tea
    • Abstract: Publication date: Available online 26 March 2016
      Source:International Journal of Food Microbiology
      Author(s): Wei Zhang, Ruijuan Yang, Wenjun Fang, Liang Yan, Jun Lu, Jun Sheng, Jie Lv
      This study aimed to characterize the thermophilic fungi in pile-fermentation process of Pu-erh tea. Physicochemical analyses showed that the high temperature and low pH provided optimal conditions for propagation of fungi. A number of fungi, including Blastobotrys adeninivorans, Thermomyces lanuginosus, Rasamsonia emersonii, Aspergillus fumigatus, Rhizomucor pusillus, Rasamsonia byssochlamydoides, Rasamsonia cylindrospora, Aspergillus tubingensis, Aspergillus niger, Candida tropicalis and Fusarium graminearum were isolated as thermophilic fungi under combination of high temperature and acid culture conditions from Pu-erh tea pile-fermentation. The fungal communities were analyzed by PCR-DGGE. Results revealed that those fungi are closely related to Debaryomyces hansenii, Cladosporium cladosporioides, A. tubingensis, R. emersonii, R. pusillus, A. fumigatus and A. niger, and the last four presented as dominant species in the pile process. These four preponderant thermophilic fungi reached the order of magnitude of 107, 107, 107 and 106 copies/g dry tea, respectively, measured by real-time quantitative PCR (q-PCR). The results indicate that the thermophilic fungi play an important role in Pu-erh tea pile fermentation.

      PubDate: 2016-03-30T13:00:47Z
  • Growth and aggressiveness factors affecting Monilinia spp. survival
    • Abstract: Publication date: Available online 28 March 2016
      Source:International Journal of Food Microbiology
      Author(s): M. Villarino, P. Melgarejo, A. De Cal
      Brown rot of stone fruit is caused by three species of Monilinia, Monilinia laxa, M. fructigena, and M. fructicola. Eleven components of 20 different isolates of each of the three Monilinia species were analyzed to determine distinct aggressiveness and growth characteristics among the three fungi. M. fructicola showed the greatest lesion diameter, and the lowest incubation and latency period on fruit postharvest, however isolates of M. fructigena exhibited less aggressiveness components. Five growth characteristics of M. fructicola could be used to distinguish M. fructicola from the other two species. The dendrogram generated from only the presence of sclerotia and lesion length on infected fruit separated the 60 isolates into two clusters (r =0.93). One cluster was composed of the M. laxa and M. fructigena isolates and the other cluster comprised the M. fructicola isolates. However, the dendrogram generated based on the presence of stromata and sclerotia in the same colony of the three species when they were grown on potato dextrose agar, and the lesion diameter on fruit infected with each species separated the 60 isolates into three clusters (r =0.81). Each cluster comprised the isolates of each of three Monilinia spp. We discussed the effect of M. fructicola growth and aggressiveness differences on the displacement of M. laxa and M. fructigena by M. fructicola recorded in Spanish peach orchards and their effect on brown rot at postharvest.

      PubDate: 2016-03-30T13:00:47Z
  • Acidified nitrite inhibits proliferation of Listeria monocytogenes —
           Transcriptional analysis of a preservation method
    • Abstract: Publication date: 2 June 2016
      Source:International Journal of Food Microbiology, Volume 226
      Author(s): Stefanie Müller-Herbst, Stefanie Wüstner, Jan Kabisch, Rohtraud Pichner, Siegfried Scherer
      Sodium nitrite (NaNO2) is added as a preservative during raw meat processing such as raw sausage production to inhibit growth of pathogenic bacteria. In the present study it was shown in challenge assays that the addition of sodium nitrite indeed inhibited growth and survival of Listeria monocytogenes in short-ripened spreadable raw sausages. Furthermore, in vitro growth analyses were performed, which took into account combinations of various parameters of the raw sausage ripening process like temperature, oxygen availability, pH, NaCl concentration, and absence or presence of NaNO2. Data based on 300 growth conditions revealed that the inhibitory effect of nitrite was most prominent in combination with acidification, a combination that is also achieved during short-ripened spreadable raw sausage production. At pH6.0 and below, L. monocytogenes was unable to replicate in the presence of 200mg/l NaNO2. During the adaptation of L. monocytogenes to acidified nitrite stress (pH6.0, 200mg/l NaNO2) in comparison to acid exposure only (pH6.0, 0mg/l NaNO2), a massive transcriptional adaptation was observed using microarray analyses. In total, 202 genes were up-regulated and 204 genes were down-regulated. In accordance with growth inhibition, a down-regulation of genes encoding for proteins which are involved in central cellular processes, like cell wall/membrane/envelope biogenesis, translation and ribosomal structure and biogenesis, transcription, and replication, recombination and repair, was observed. Among the up-regulated genes the most prominent group belonged to poorly characterized genes. A considerable fraction of the up-regulated genes has been shown previously to be up-regulated intracellularly in macrophages, after exposure to acid shock or to be part of the SigB regulon. These data indicate that the adaptation to acidified nitrite partly overlaps with the adaptation to stress conditions being present during host colonization.

      PubDate: 2016-03-30T13:00:47Z
  • Synergistic bactericidal action of phytic acid and sodium chloride against
           Escherichia coli O157:H7 cells protected by a biofilm
    • Abstract: Publication date: Available online 29 March 2016
      Source:International Journal of Food Microbiology
      Author(s): Nam Hee Kim, Min Suk Rhee
      The food industry must prevent the build-up of strong Escherichia coli O157:H7 biofilms in food processing environments. The present study examined the bactericidal action of phytic acid (PA), a natural extract from rice bran and the hulls/peels of legumes, against E. coli O157:H7 biofilms. The synergistic bactericidal effects of PA plus sodium chloride (NaCl) were also examined. E. coli O157:H7 biofilms were allowed for form on stainless steel coupons by culture in both rich (tryptic soy broth, TSB) and minimal (M9) medium at 22°C for 6days. Bacterial cells within biofilms grown in M9 medium were significantly more resistant to PA than those grown in TSB (p <0.05); thus M9 medium was selected for further experiments. The anti-biofilm effect of PA was significantly increased by addition of NaCl (2–4%) (p <0.05); indeed, the combination of 0.4% PA plus 3–4% NaCl completely inactivated E. coli O157:H7 biofilms without recovery (a>6.5logCFU/cm2 reduction). Neither PA nor NaCl alone were this effective (PA, 1.6–2.7logCFU/cm2 reduction; NaCl, <0.5logCFU/cm2 reduction). Confocal laser scanning microscopy images of propidium iodide-treated cells showed that PA (0.4%) plus NaCl (2–4%) had marked membrane permeabilizing effects. These results suggest that a sanitizer that combines these two naturally occurring antimicrobial agents may be useful to food safety managers who encounter thick biofilm formation in food processing environments.

      PubDate: 2016-03-30T13:00:47Z
  • Genotypic diversity of Lactobacillus sanfranciscensis strains isolated
           from French organic sourdoughs
    • Abstract: Publication date: 2 June 2016
      Source:International Journal of Food Microbiology, Volume 226
      Author(s): Emilie Lhomme, Bernard Onno, Victoria Chuat, Karine Durand, Servane Orain, Florence Valence, Xavier Dousset, Marie-Agnès Jacques
      Lactobacillus sanfranciscensis is the predominant key lactic acid bacterium in traditionally fermented sourdoughs. Despite its prevalence, sourdough and their related breads could be different regarding their physicochemical and sensorial characteristics. The intraspecific diversity of L. sanfranciscensis might explain these observations. Fifty-nine strains isolated from French sourdoughs were typed by a polyphasic approach including Multilocus Sequence Typing (MLST) and Pulsed-field Gel Electrophoresis (PFGE), in order to study their genotypic diversity. MLST scheme can be reduced from six to four gene fragments (gdh, gyrA, nox and pta) without a major loss of discrimination between strains. The genes mapA and pgmA are not good candidates for inclusion in an MLST scheme to type L. sanfranciscensis strains, as they could not be amplified for a set of 18 strains among the 59 studied. This method revealed 20 sequence types (STs). Of these, 19 STs were grouped in one clonal complex, showing a strong relatedness between these strains. PFGE using SmaI discriminated 41 pulsotypes and so distinguished isolates better than the MLST scheme. Both genotypic methods indicate a low diversity between strains isolated from the same sourdough and a higher diversity between strains isolated from different sourdoughs, suggesting an influence of baker practices and/or environmental conditions on the selection of strains. The use of these two methods targeting genetic variations gives an optimal genotypic characterization of L. sanfranciscensis strains.

      PubDate: 2016-03-30T13:00:47Z
  • Identification of risk factors for Campylobacter contamination levels on
           broiler carcasses during the slaughter process
    • Abstract: Publication date: Available online 18 March 2016
      Source:International Journal of Food Microbiology
      Author(s): Tomasz Seliwiorstow, Julie Baré, Dirk Berkvens, Inge Van Damme, Mieke Uyttendaele, Lieven De Zutter
      Campylobacter carcass contamination was quantified across the slaughter line during processing of Campylobacter positive batches. These quantitative data were combined together with information describing slaughterhouse and batch related characteristics in order to identify risk factors for Campylobacter contamination levels on broiler carcasses. The results revealed that Campylobacter counts are influenced by the contamination of incoming birds (both the initial external carcass contamination and the colonization level of caeca) and the duration of transport and holding time being that linked with feed withdrawal period. In addition, technical aspects of the slaughter process such as a dump based unloading system, electrical stunning, lower scalding temperature, incorrect setting of plucking, vent cutter and evisceration machines were identified as risk factors associated with increased Campylobacter counts on processed carcasses. As such the study indicates possible improvements of the slaughter process that can result in the better control of Campylobacter numbers under routine processing of Campylobacter positive batches without use of chemical or physical decontamination. Moreover, all investigated factors were existing variations of the routine processing practices and therefore proposed interventions are practically and economically achievable.

      PubDate: 2016-03-21T11:17:30Z
  • Repeat-based Sequence Typing of Carnobacterium maltaromaticum
    • Abstract: Publication date: 2 June 2016
      Source:International Journal of Food Microbiology, Volume 226
      Author(s): Abdur Rahman, Sara M. El Kheir, Alexandre Back, Cécile Mangavel, Anne-Marie Revol-Junelles, Frédéric Borges
      Carnobacterium maltaromaticum is a Lactic Acid Bacterium (LAB) of technological interest for the food industry, especially the dairy as bioprotection and ripening flora. The industrial use of this LAB requires accurate and resolutive typing tools. A new typing method for C. maltaromaticum inspired from MLVA analysis and called Repeat-based Sequence Typing (RST) is described. Rather than electrophoresis analysis, our RST method is based on sequence analysis of multiple loci containing Variable-Number Tandem-Repeats (VNTRs). The method described here for C. maltaromaticum relies on the analysis of three VNTR loci, and was applied to a collection of 24 strains. For each strain, a PCR product corresponding to the amplification of each VNTR loci was sequenced. Sequence analysis allowed delineating 11, 11, and 12 alleles for loci VNTR-A, VNTR-B, and VNTR-C, respectively. Considering the allele combination exhibited by each strain allowed defining 15 genotypes, ending in a discriminatory index of 0.94. Comparison with MLST revealed that both methods were complementary for strain typing in C. maltaromaticum.

      PubDate: 2016-03-21T11:17:30Z
  • Antimicrobial properties of microemulsions formulated with essential oils,
           soybean oil, and tween 80
    • Abstract: Publication date: Available online 17 March 2016
      Source:International Journal of Food Microbiology
      Author(s): Qiumin Ma, P. Michael Davidson, Qixin Zhong
      It was previously found that blending soybean oil with cinnamon bark oil (CBO), eugenol or thyme oil, Tween 80, and equal masses of water and propylene glycol could be used to prepare microemulsions. In the present study, the objective was to determine the antimicrobial activity of the microemulsions in tryptic soy broth (TSB) and 2% reduced fat milk. In TSB, the minimum inhibitory concentration (MIC) of CBO solubilized in microemulsions was up to 625ppm against cocktails of Listeria monocytogenes, Salmonella enterica or Escherichia coli O157:H7, which was equal to or higher in concentration than free CBO dissolved in ethanol. However, MICs of eugenol or thyme oil in microemulsions were much higher than that of free antimicrobials. Therefore, microemulsions of CBO were chosen to do further study. Inactivation curves of L. monocytogenes or E. coli O157:H7 in TSB or 2% reduced fat milk were tested and fitted using the Weibull model. In TSB, a gradual decrease in cell viability of L. monocytogenes and E. coli O157:H7 was observed with the microemulsion treatments at 625ppm CBO, which was in contrast to the more rapid and greater inactivation by free CBO. Gradual inactivation of L. monocytogenes in 2% reduced fat milk was also observed in the treatment with 10,000ppm free or microemulsified CBO. When fitted using the Weibull model, the predicted time to obtain a 3-log decrease of L. monocytogenes and E. coli O157:H7 in TSB or 2% reduced fat milk increased with an increased amount of soybean oil in microemulsions. Additionally, increasing the amount of Tween 80 in mixtures with different mass ratios of Tween 80 and essential oils significantly decreased the log reductions of L. monocytogenes in TSB. Our study showed that microemulsions can be used to dissolve EOs and control the rate of inactivating bacteria, but the composition of microemulsions is to be carefully chosen to minimize the reduction of antimicrobial activities.

      PubDate: 2016-03-21T11:17:30Z
  • Evaluation of a cross contamination model describing transfer of
           Salmonella spp. And Listeria monocytogenes during grinding of pork and
    • Abstract: Publication date: Available online 17 March 2016
      Source:International Journal of Food Microbiology
      Author(s): C.O.A. Møller, A.S. Sant'Ana, S.K.H. Hansen, M.J. Nauta, L.P. Silva, V.O. Alvarenga, D. Maffei, F.F.P. Silva, J.T. Lopes, B.D.G.M. Franco, S. Aabo, T.B. Hansen
      In a previous study, a model was developed to describe the transfer and survival of Salmonella during grinding of pork (Møller, C.O.A., Nauta, M.J., Christensen, B.B., Dalgaard, P., Hansen, T.B., 2012. Modelling transfer of Salmonella Typhimurium DT104 during simulation of grinding of pork. Journal of Applied Microbiology 112 (1), 90–98). The robustness of this model is now evaluated by studying its performance for predicting the transfer and survival of Salmonella spp. and Listeria monocytogenes during grinding of different types of meat (pork and beef), using two different grinders, different sizes and different numbers of pieces of meats to be ground. A total of 19 grinding trials were collected. Acceptable Simulation Zone (ASZ), visual inspection of the data, Quantitative Microbiological Risk Assessment (QMRA), as well as the Total Transfer Potential (TTP) were used as approaches to evaluate model performance and to access the quality of the cross contamination model predictions. Using the ASZ approach and considering that 70% of the observed counts have to be inside a defined acceptable zone of ±0.5 log10CFU per portion, it was found that the cross contamination parameters suggested by Møller et al. (2012) were not able to describe all 19 trials. However, for each of the collected grinding trials, the transfer event was well described when fitted to the model structure proposed by Møller et al. (2012). Parameter estimates obtained by fitting observed trials performed at different conditions, such as size and number of pieces of meat to be ground, may not be applied to describe cross contamination of unlike processing. Nevertheless, the risk estimates, as well as the TTP, revealed that the risk of disease may be reduced when the grinding of meat is performed in a grinder made of stainless steel (for all surfaces in contact with the meat), using a well-sharpened knife and holding at room temperatures lower than 4°C.

      PubDate: 2016-03-17T11:07:06Z
  • Improvement of aromatic thiol release through the selection of yeasts with
           increased β-lyase activity
    • Abstract: Publication date: Available online 3 March 2016
      Source:International Journal of Food Microbiology
      Author(s): Ignacio Belda, Javier Ruiz, Eva Navascués, Domingo Marquina, Antonio Santos
      The development of a selective medium for the rapid differentiation of yeast species with increased aromatic thiol release activity has been achieved. The selective medium was based on the addition of S-methyl-l-cysteine (SMC) as β-lyase substrate. In this study, a panel of 245 strains of Saccharomyces cerevisiae strains was tested for their ability to grow on YCB-SMC medium. Yeast strains with an increased β-lyase activity grew rapidly because of their ability to release ammonium from SMC in comparison to others, and allowed for the easy isolation and differentiation of yeasts with promising properties in oenology, or another field, for aromatic thiol release. The selective medium was also helpful for the discrimination between those S. cerevisiae strains, which present a common 38-bp deletion in the IRC7 sequence (present in around 88% of the wild strains tested and are likely to be less functional for 4-mercapto-4-methylpentan-2-one (4MMP) production), and those S. cerevisiae strains homozygous for the full-length IRC7 allele. The medium was also helpful for the selection of non-Saccharomyces yeasts with increased β-lyase activity. Based on the same medium, a highly sensitive, reproducible and non-expensive GC–MS method for the evaluation of the potential volatile thiol release by different yeast isolates was developed.

      PubDate: 2016-03-08T23:59:10Z
  • Selection of lactic acid bacteria isolated from Tunisian cereals and
           exploitation of the use as starters for sourdough fermentation
    • Abstract: Publication date: Available online 5 March 2016
      Source:International Journal of Food Microbiology
      Author(s): Asma Mamhoud, Luana Nionelli, Taroub Bouzaine, Moktar Hamdi, Marco Gobbetti, Carlo Giuseppe Rizzello
      Wheat bread is the most popular staple food consumed in Tunisia and, despite the niche production of some typical breads (e.g. Tabouna, Mlawi, Mtabga), the major part is currently produced with baker's yeast at industrial or, mainly, at artisanal level, while the use of sourdough fermentation is rarely reported. Considering the growing national demand for cereal baked goods, it can be hypothesized that sourdough fermentation through the use of selected lactic acid bacteria as starters could improve the overall quality and the diversification of local products. Different cereal grains were collected from the regions of Ariana, Bizerta, Beja Nabeul, and Seliana, and the autochthonous lactic acid bacteria were isolated, identified, characterized and selected on the basis of the kinetics of acidification, the proteolytic activity, and the quotient of fermentation. Lactobacillus curvatus MA2, Pediococcus pentosaceus OA2, and Pediococcus acidilactici O1A1 were used together as mixed starter to obtain a selected sourdough. According to the back slopping procedure, a type I sourdough was made from a Tunisian flour (spontaneous sourdough). Compared to the use of the spontaneous sourdough, the one obtained with selected and mixed starters by a unique fermentation step, favored the increase of the concentrations of organic acids, phenols, and total free amino acids, the most suitable quotient of fermentation, and the most intense phytase and antioxidant activities, that increased of ca. 20% compared to the control. Moreover, the selected starters improved the in vitro protein digestibility (ca. 82% when selected sourdough was used), textural and sensory features of the breads, as determined by textural profile analysis and panel test, respectively. This study aimed at exploiting the potential of selected autochthonous lactic acid bacteria and extending the use of a sourdough (type II), thanks to the set-up of a two-step fermentation protocol designed for the application at industrial level, and the confirmed nutritional, textural, and sensory advantages on the final product.

      PubDate: 2016-03-08T23:59:10Z
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