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  Subjects -> BIOLOGY (Total: 2958 journals)
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MICROBIOLOGY (254 journals)                  1 2     

Showing 1 - 0 of 0 Journals sorted alphabetically
Acta Microbiologica et Immunologica Hungarica     Full-text available via subscription   (Followers: 5)
Addiction Genetics     Open Access   (Followers: 5)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 16)
Advances in Microbiology     Open Access   (Followers: 17)
Advances in Molecular Imaging     Open Access   (Followers: 1)
African Journal of Clinical and Experimental Microbiology     Open Access  
African Journal of Microbiology Research     Open Access   (Followers: 1)
Algorithms for Molecular Biology     Open Access   (Followers: 4)
American Journal of Infectious Diseases and Microbiology     Open Access   (Followers: 17)
American Journal of Microbiological Research     Open Access   (Followers: 2)
American Journal of Microbiology     Open Access   (Followers: 13)
American Journal of Molecular Biology     Open Access   (Followers: 2)
American Journal of Stem Cell Research     Open Access   (Followers: 3)
Annals of Clinical Microbiology and Antimicrobials     Open Access   (Followers: 7)
Annals of Microbiology     Hybrid Journal   (Followers: 9)
Annual Review of Microbiology     Full-text available via subscription   (Followers: 33)
Antimicrobial Agents and Chemotherapy     Hybrid Journal   (Followers: 19)
Antiviral Research     Hybrid Journal   (Followers: 7)
Applied and Environmental Microbiology     Hybrid Journal   (Followers: 38)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 17)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 58)
Aquatic Microbial Ecology     Hybrid Journal   (Followers: 2)
Archives of Microbiology     Hybrid Journal   (Followers: 7)
Avicenna Journal of Clinical Microbiology and Infection     Open Access   (Followers: 1)
Bangladesh Journal of Medical Microbiology     Open Access  
Beneficial Microbes     Full-text available via subscription   (Followers: 2)
Bio-Research     Full-text available via subscription  
BioArchitecture     Full-text available via subscription  
Bioethanol     Open Access  
Biomaterials Science     Full-text available via subscription   (Followers: 8)
BioMolecular Concepts     Hybrid Journal   (Followers: 2)
Biomolecular Detection and Quantification     Open Access  
Biomolecules     Open Access   (Followers: 1)
Biotechnology and Molecular Biology Reviews     Open Access  
BMC Microbiology     Open Access   (Followers: 8)
Brazilian Journal of Microbiology     Open Access   (Followers: 2)
Canadian Journal of Infectious Diseases and Medical Microbiology     Open Access   (Followers: 2)
Canadian Journal of Microbiology     Full-text available via subscription   (Followers: 3)
Cell Biology : Research & Therapy     Hybrid Journal   (Followers: 2)
Cell Host & Microbe     Full-text available via subscription   (Followers: 14)
Cell Medicine     Open Access   (Followers: 3)
Cell Regeneration     Open Access   (Followers: 1)
Cell Stem Cell     Full-text available via subscription   (Followers: 30)
CellBio     Open Access  
Cells     Open Access   (Followers: 1)
Cellular & Molecular Immunology     Hybrid Journal   (Followers: 11)
Cellular and Molecular Biology Letters     Open Access   (Followers: 1)
Cellular and Molecular Life Sciences (CMLS)     Hybrid Journal   (Followers: 6)
Cellular Microbiology     Hybrid Journal   (Followers: 7)
Cheese: Chemistry, Physics and Microbiology     Full-text available via subscription   (Followers: 2)
Chimerism     Full-text available via subscription  
Clinical Microbiology and Infection     Hybrid Journal   (Followers: 16)
Clinical Microbiology Newsletter     Hybrid Journal   (Followers: 4)
Clinical Microbiology Reviews     Hybrid Journal   (Followers: 15)
Comparative Immunology, Microbiology and Infectious Diseases     Hybrid Journal   (Followers: 10)
Computational Molecular Bioscience     Open Access   (Followers: 1)
Critical Reviews in Microbiology     Hybrid Journal   (Followers: 11)
Current Clinical Microbiology Reports     Hybrid Journal   (Followers: 1)
Current Issues in Molecular Biology     Open Access   (Followers: 2)
Current Microbiology     Hybrid Journal   (Followers: 9)
Current Molecular Biology Reports     Hybrid Journal   (Followers: 1)
Current Molecular Imaging     Hybrid Journal  
Current Opinion in Microbiology     Hybrid Journal   (Followers: 29)
Current Tissue Engineering     Hybrid Journal   (Followers: 2)
Current Topics in Microbiology and Immunology     Hybrid Journal   (Followers: 8)
Diagnostic Microbiology and Infectious Disease     Hybrid Journal   (Followers: 8)
Disease and Molecular Medicine     Open Access   (Followers: 1)
DNA Barcodes     Open Access  
Egyptian Journal of Biochemistry and Molecular Biology     Full-text available via subscription  
Emerging Microbes & Infections     Open Access   (Followers: 2)
Environmental Microbiology     Hybrid Journal   (Followers: 13)
Environmental Microbiology Reports     Hybrid Journal   (Followers: 3)
Enzyme and Microbial Technology     Hybrid Journal   (Followers: 12)
Epigenetics of Degenerative Diseases     Open Access   (Followers: 5)
European Journal of Clinical Microbiology & Infectious Diseases     Hybrid Journal   (Followers: 17)
European Journal of Microbiology and Immunology     Open Access   (Followers: 8)
Experimental and Molecular Pathology     Hybrid Journal   (Followers: 4)
Experimental Cell Research     Hybrid Journal   (Followers: 6)
Fems Microbiology Ecology     Hybrid Journal   (Followers: 8)
Fems Microbiology Letters     Hybrid Journal   (Followers: 18)
Fems Microbiology Reviews     Hybrid Journal   (Followers: 23)
Fermentation     Open Access   (Followers: 1)
Folia Histochemica et Cytobiologica     Open Access  
Folia Microbiologica     Hybrid Journal   (Followers: 1)
Food Microbiology     Hybrid Journal   (Followers: 15)
Frontiers in Cell and Developmental Biology     Open Access   (Followers: 3)
Frontiers in Cellular and Infection Microbiology     Open Access   (Followers: 3)
Frontiers in Cellular Neuroscience     Open Access   (Followers: 5)
Frontiers in Microbiology     Open Access   (Followers: 8)
Frontiers in Molecular Neuroscience     Open Access   (Followers: 3)
Future Microbiology     Hybrid Journal   (Followers: 4)
Future Virology     Hybrid Journal   (Followers: 7)
Gene Expression     Full-text available via subscription  
Genetica si Biologie Moleculara     Open Access  
Genetics and Molecular Research     Open Access   (Followers: 4)
Geomicrobiology Journal     Hybrid Journal   (Followers: 2)
Gut Microbes     Full-text available via subscription   (Followers: 8)
IAWA Journal     Hybrid Journal  
Indian Journal of Microbiology     Hybrid Journal   (Followers: 2)
Indian Journal of Pathology and Microbiology     Open Access   (Followers: 1)
Infection Ecology & Epidemiology     Open Access   (Followers: 3)
Inside the Cell     Open Access  
International Journal of Antimicrobial Agents     Hybrid Journal   (Followers: 6)
International Journal of Bacteriology     Open Access  
International Journal of Bioassays     Open Access   (Followers: 2)
International Journal of Biotechnology and Molecular Biology Research     Open Access   (Followers: 2)
International Journal of Food Microbiology     Hybrid Journal   (Followers: 12)
International Journal of Genetics and Molecular Biology     Open Access  
International Journal of Infection and Microbiology     Open Access   (Followers: 1)
International Journal of Medical Microbiology     Hybrid Journal   (Followers: 7)
International Journal of Molecular Medicine     Full-text available via subscription   (Followers: 5)
International Journal of Mycobacteriology     Open Access  
International Journal of Systematic and Evolutionary Microbiology     Full-text available via subscription   (Followers: 3)
International Journal of Virology and Molecular Biology     Open Access  
International Microbiology     Open Access   (Followers: 3)
Invertebrate Immunity     Open Access   (Followers: 1)
JMM Case Reports     Open Access  
Journal of Cell Science & Therapy     Open Access   (Followers: 2)
Journal of Microbial & Biochemical Technology     Open Access   (Followers: 1)
Journal of Applied Biology & Biotechnology     Open Access   (Followers: 1)
Journal of Applied Microbiology     Hybrid Journal   (Followers: 11)
Journal of Bacteriology     Hybrid Journal   (Followers: 26)
Journal of Basic Microbiology     Hybrid Journal   (Followers: 3)
Journal of Biomolecular Structure and Dynamics     Hybrid Journal   (Followers: 2)
Journal of Bionanoscience     Full-text available via subscription  
Journal of Brewing and Distilling     Open Access   (Followers: 1)
Journal of Cell and Animal Biology     Open Access  
Journal of Cell Biology and Genetics     Open Access   (Followers: 2)
Journal of Clinical Microbiology     Hybrid Journal   (Followers: 28)
Journal of Clinical Pathology     Full-text available via subscription   (Followers: 11)
Journal of Extracellular Vesicles     Open Access   (Followers: 4)
Journal of Food Microbiology     Open Access   (Followers: 3)
Journal of General and Molecular Virology     Open Access  
Journal of Genes and Cells     Open Access  
Journal of Global Antimicrobial Resistance     Hybrid Journal   (Followers: 2)
Journal of Industrial Microbiology and Biotechnology     Hybrid Journal   (Followers: 14)
Journal of Medical Microbiology     Full-text available via subscription   (Followers: 3)
Journal of Microbiological Methods     Hybrid Journal   (Followers: 2)
Journal of Microbiology     Hybrid Journal   (Followers: 7)
Journal of Microbiology and Antimicrobials     Open Access   (Followers: 2)
Journal of Microbiology Research     Open Access   (Followers: 2)
Journal of Micropalaeontology     Hybrid Journal   (Followers: 7)
Journal of Molecular Biochemistry     Open Access   (Followers: 3)
Journal of Molecular Biology Research     Open Access   (Followers: 3)
Journal of Molecular Microbiology and Biotechnology     Full-text available via subscription   (Followers: 12)
Journal of Molecular Pathophysiology     Open Access   (Followers: 1)
Journal of Molecular Psychiatry     Open Access   (Followers: 9)
Journal of Morphology     Hybrid Journal   (Followers: 3)
Journal of Pharmacy & Bioresources     Full-text available via subscription   (Followers: 3)
Journal of Plant Molecular Biology and Biotechnology     Open Access   (Followers: 7)
Journal of Plant Pathology & Microbiology     Open Access  
Journal of Proteome Science and Computational Biology     Open Access  
Journal of Regenerative Medicine and Tissue Engineering     Open Access   (Followers: 3)
Journal of The Academy of Clinical Microbiologists     Open Access  
Journal of the American Society of Brewing Chemists     Full-text available via subscription   (Followers: 2)
Journal of the Institute of Brewing     Free   (Followers: 1)
Journal of Tropical Microbiology and Biotechnology     Full-text available via subscription  
Jundishapur Journal of Microbiology     Open Access  
Letters In Applied Microbiology     Hybrid Journal   (Followers: 5)
Macrophage     Open Access  
MAP Kinase     Open Access  
Medical Mycology     Open Access   (Followers: 4)
Memórias do Instituto Oswaldo Cruz     Open Access  
Methods in Molecular Biology     Hybrid Journal   (Followers: 23)
Microbes and Health     Open Access   (Followers: 1)
Microbes and Infection     Full-text available via subscription   (Followers: 4)
Microbial Biotechnology     Open Access   (Followers: 7)
Microbial Cell Factories     Open Access   (Followers: 7)
Microbial Drug Resistance     Hybrid Journal   (Followers: 4)
Microbial Ecology     Hybrid Journal   (Followers: 6)
Microbial Ecology in Health and Disease     Open Access  
Microbial Informatics and Experimentation     Open Access   (Followers: 1)
Microbial Pathogenesis     Hybrid Journal   (Followers: 6)
Microbial Risk Analysis     Full-text available via subscription  
Microbiologia Medica     Open Access   (Followers: 1)
Microbiological Research     Hybrid Journal   (Followers: 6)
Microbiology     Hybrid Journal   (Followers: 12)
Microbiology (SGM)     Full-text available via subscription   (Followers: 16)
Microbiology and Immunology     Hybrid Journal   (Followers: 10)
Microbiology and Molecular Biology Reviews     Hybrid Journal   (Followers: 22)
Microbiology Australia     Hybrid Journal  
Microbiology Discovery     Open Access  
Microbiology Indonesia     Open Access  
Microbiology Research     Open Access   (Followers: 7)
MicrobiologyOpen     Open Access   (Followers: 2)
Microbiome     Hybrid Journal   (Followers: 5)
Microbiome Science and Medicine     Open Access  
Microorganisms     Open Access   (Followers: 2)
MicroRNA     Hybrid Journal   (Followers: 1)
Molecular and Cellular Therapies     Open Access  
Molecular Biology and Genetic Engineering     Open Access   (Followers: 1)
Molecular Biology Research Communications     Open Access   (Followers: 1)
Molecular Genetics and Metabolism Reports     Open Access   (Followers: 1)
Molecular Genetics, Microbiology and Virology     Hybrid Journal   (Followers: 6)
Molecular Imaging     Open Access  
Molecular Imaging and Biology     Hybrid Journal   (Followers: 2)
Molecular Medicine     Open Access   (Followers: 1)
Molecular Medicine Reports     Full-text available via subscription   (Followers: 6)
Molecular Microbiology     Hybrid Journal   (Followers: 26)
Molecular Oral Microbiology     Partially Free   (Followers: 3)

        1 2     

Journal Cover International Journal of Food Microbiology
  [SJR: 1.64]   [H-I: 142]   [12 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0168-1605
   Published by Elsevier Homepage  [3039 journals]
  • High hydrostatic pressure inactivation of murine norovirus and human
           noroviruses on green onions and in salsa
    • Authors: Robert F. Sido; Runze Huang; Chuhan Liu; Haiqiang Chen
      Pages: 1 - 6
      Abstract: Publication date: 2 February 2017
      Source:International Journal of Food Microbiology, Volume 242
      Author(s): Robert F. Sido, Runze Huang, Chuhan Liu, Haiqiang Chen
      In this study, high hydrostatic pressure (HHP) was evaluated as an intervention for human noroviruses (HuNoVs) in green onions and salsa. To determine the effect of water during HHP treatment on virus inactivation, a HuNoV surrogate, murine norovirus 1 (MNV-1), was inoculated onto green onions and then HHP-treated at 350MPa with or without water at 4 or 20°C. The presence of water enhanced HHP inactivation of MNV-1 on green onions at 4°C but not at 20°C. To test the temperature effect on HHP inactivation of MNV-1, inoculated green onions were HHP-treated at 300MPa at 1, 4 and 10°C. As the temperature decreased, MNV-1 became more sensitive to HHP treatment. HHP inactivation curves of MNV-1 on green onions and salsa were obtained at 300 or 350MPa for 0.5–3min at 1°C. All three inactivation curves showed a linear relationship between log reduction of MNV-1 and time. D values of HHP inactivation of MNV-1 on green onions were 1.10 and 0.61min at 300 and 350MPa, respectively. The D value of HHP inactivation of MNV-1 in salsa at 300MPa was 0.63min. HHP inactivation of HuNoV GI.1 and GII.4 on green onions and salsa was also conducted. To achieve >3 log reduction of HuNoV GI.1, HHP treatments for 2min at 1°C should be conducted at 600MPa and 500MPa for green onions and salsa, respectively. To achieve >3 log reduction of HuNoV GII.4, HHP treatments for 2min at 1°C should be conducted at 500MPa and 300MPa for green onions and salsa, respectively.

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

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

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

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

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

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

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

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

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

      PubDate: 2016-12-01T07:14:43Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.016
      Issue No: Vol. 242 (2016)
       
  • Antifungal activity of 1-methylcyclopropene (1-MCP) against anthracnose
           (Colletotrichum gloeosporioides) in postharvest mango fruit and its
           possible mechanisms of action
    • Authors: Xiangbin Xu; Huanhuan Lei; Xiuyan Ma; Tongfei Lai; Hongmiao Song; Xuequn Shi; Jiangkuo Li
      Pages: 1 - 6
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Xiangbin Xu, Huanhuan Lei, Xiuyan Ma, Tongfei Lai, Hongmiao Song, Xuequn Shi, Jiangkuo Li
      Anthracnose caused by Colletotrichum gloeosporioides is one of the most important postharvest diseases in mango fruit, often causing huge economic losses. In this study, the effect of 1-methylcyclopropene (1-MCP) against anthracnose in postharvest mango fruit and the mechanisms involved were investigated. 1-MCP induced reactive oxygen species (ROS) generation, damaged the mitochondria and destroyed the integrity of plasma membrane of spores of C. gloeosporioides, significantly suppressing spore germination and mycelial growth of C. gloeosporioides. 1-MCP also decreased the decay incidence and lesion expansion of mango fruit caused by C. gloeosporioides. For the first time this study demonstrated that 1-MCP suppressed anthracnose of postharvest mango fruit by directly inhibiting spore germination and mycelial growth of C. gloeosporioides, thus providing a promising strategy for disease control.

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

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

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

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

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

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

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

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

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

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

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

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

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

      PubDate: 2016-10-20T14:16:42Z
      DOI: 10.1016/j.ijfoodmicro.2016.09.010
      Issue No: Vol. 241 (2016)
       
  • Antimicrobial effect of the Tunisian Nana variety Punica granatum L.
           extracts against Salmonella enterica (serovars Kentucky and Enteritidis)
           isolated from chicken meat and phenolic composition of its peel extract
    • Authors: Ben Ajmia Wafa; Mohamed Makni; Sonda Ammar; Lamia Khannous; Amal Ben Hassana; Mohamed Bouaziz; Nour Eddine Es-Safi; Radhouane Gdoura
      Pages: 123 - 131
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Ben Ajmia Wafa, Mohamed Makni, Sonda Ammar, Lamia Khannous, Amal Ben Hassana, Mohamed Bouaziz, Nour Eddine Es-Safi, Radhouane Gdoura
      Punica granatum L. is widely recognized for its potency against a broad spectrum of bacterial pathogens. The purpose of this study was to explore the inhibitory and the bactericidal activities of Punica granatum against Salmonella strains. The effect of extracts obtained from different parts (peels, seeds, juice and flowers) of pomegranate and using different solvents against Salmonella enterica serovars Kentucky and Enteritidis isolated from chicken meat was thus investigated. Salmonella strains were identified with the standard API-20E system and confirmed by real time PCR. The obtained results showed that the highest antibacterial activity against Salmonella strains was observed with the peels ethanolic extract giving MIC values ranging from 10.75 to 12.5mg/mL. The ethanolic extract of P. granatum Nana peels at 0.8 and 1.6mg/g significantly inhibited the growth of Salmonella Kentucky in chicken meat stored at 4°C. The phenolic composition of the ethanolic peel extract was explored by HPLC coupled to both DAD and ESI/TOF-MS detections. The obtained results allowed the detection of 21 phytochemical compounds among which various phenolic compounds have been identified on the basis of their UV and MS spectra as well as with literature data. Among the detected compounds, anthocyanins, ellagitannins, ellagic acid derivatives and flavanols were further characterized through MS-MS analysis. Our results showed thus that the Tunisian variety Nana pomegranate constitutes a good source of bioactive compounds with potent antimicrobial activity on the growth of Salmonella strains suggesting that the studied pomegranate cultivar could be a natural remedy to minimize the emergence of Salmonella enterica strains which is often involved in food borne illness.

      PubDate: 2016-10-27T21:43:47Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.007
      Issue No: Vol. 241 (2016)
       
  • Activity of essential oil-based microemulsions against Staphylococcus
           aureus biofilms developed on stainless steel surface in different culture
           media and growth conditions
    • Authors: Campana Raffaella; Luca Casettari; Laura Fagioli; Marco Cespi; Giulia Bonacucina; Wally Baffone
      Pages: 132 - 140
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Campana Raffaella, Luca Casettari, Laura Fagioli, Marco Cespi, Giulia Bonacucina, Wally Baffone
      Food safety is a fundamental concern for both consumers and the food industry, especially as the numbers of reported cases of food-associated infections continue to increase. Industrial surfaces can provide a suitable substrate for the development and persistence of bacterial organized in biofilms that represent a potential source of food contamination. The negative consumer perception of chemical disinfectants has shifted the attention to natural substances, such as plant extracts. The aim of this study was to investigate the possibility of using the essential oils (EOs) in the fight against S. aureus biofilms. First, the Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), Minimum Biofilm Inhibitory Concentration (MBIC), Minimum Biofilm Eradication Concentration (MBEC) of eleven EOs against S. aureus were determined. Cinnamomum cassia and Salvia officinalis EOs showed the greatest antibacterial properties with 1.25% MIC and MBC, 1.25% MBIC and 2.5% MBEC respectively. Gas Chromatography/Mass Spectrometry analysis revealed cinnamaldehyde (82.66%) and methoxy cinnamaldehyde (10.12%) as the most abundant substances of C. cassia, while cis-thujone (23.90%), camphor (19.22%) and 1.8-cineole (10.62%) of S. officinalis. Three different microemulsions, formulated with C. cassia, S. officinalis or both, were finally tested against S. aureus biofilms in different culture media and growth conditions, causing a >3 logarithmic reductions in S. aureus 24h-old biofilms and desiccated biofilms, and up to 68% of biofilm removal after 90min of exposure. The obtained data suggest the potential use of EOs, alone or in combination, for the formulation of sanitizers as alternative or in support in the disinfection of contaminated surfaces.

      PubDate: 2016-10-20T14:16:42Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.021
      Issue No: Vol. 241 (2016)
       
  • Functional diversity within the Penicillium roqueforti species
    • Authors: Guillaume Gillot; Jean-Luc Jany; Elisabeth Poirier; Marie-Bernadette Maillard; Stella Debaets; Anne Thierry; Emmanuel Coton; Monika Coton
      Pages: 141 - 150
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Guillaume Gillot, Jean-Luc Jany, Elisabeth Poirier, Marie-Bernadette Maillard, Stella Debaets, Anne Thierry, Emmanuel Coton, Monika Coton
      Penicillium roqueforti is used as a ripening culture for blue cheeses and largely contributes to their organoleptic quality and typical characteristics. Different types of blue cheeses are manufactured and consumed worldwide and have distinct aspects, textures, flavors and colors. These features are well accepted to be due to the different manufacturing methods but also to the specific P. roqueforti strains used. Indeed, inoculated P. roqueforti strains, via their proteolytic and lipolytic activities, have an effect on both blue cheese texture and flavor. In particular, P. roqueforti produces a wide range of flavor compounds and variations in their proportions influence the flavor profiles of this type of cheese. Moreover, P. roqueforti is also characterized by substantial morphological and genetic diversity thus raising the question about the functional diversity of this species. In this context, 55 representative strains were screened for key metabolic properties including proteolytic activity (by determining free NH2 amino groups) and secondary metabolite production (aroma compounds using HS-Trap GC–MS and mycotoxins via LC-MS/Q-TOF). Mini model cheeses were used for aroma production and proteolysis analyses, whereas Yeast Extract Sucrose (YES) agar medium was used for mycotoxin production. Overall, this study highlighted high functional diversity among isolates. Noteworthy, when only P. roqueforti strains isolated from Protected Designation of Origin (PDO) or Protected Geographical Indication (PGI) blue cheeses were considered, a clear relationship between genetic diversity, population structure and the assessed functional traits was shown.

      PubDate: 2016-10-27T21:43:47Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.001
      Issue No: Vol. 241 (2016)
       
  • Temperature, water activity and pH during conidia production affect the
           physiological state and germination time of Penicillium species
    • Authors: Nicolas Nguyen Van Long; Valérie Vasseur; Louis Coroller; Philippe Dantigny; Sophie Le Panse; Amélie Weill; Jérôme Mounier; Karim Rigalma
      Pages: 151 - 160
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Nicolas Nguyen Van Long, Valérie Vasseur, Louis Coroller, Philippe Dantigny, Sophie Le Panse, Amélie Weill, Jérôme Mounier, Karim Rigalma
      Conidial germination and mycelial growth are generally studied with conidia produced under optimal conditions to increase conidial yield. Nonetheless, the physiological state of such conidia most likely differs from those involved in spoilage of naturally contaminated food. The present study aimed at investigating the impact of temperature, pH and water activity (a w ) during production of conidia on the germination parameters and compatible solutes of conidia of Penicillium roqueforti and Penicillium expansum. Low temperature (5°C) and reduced a w (0.900 a w ) during sporulation significantly reduced conidial germination times whereas the pH of the sporulation medium only had a slight effect at the tested values (2.5, 8.0). Conidia of P. roqueforti produced at 5°C germinated up to 45h earlier than those produced at 20°C. Conidia of P. roqueforti and P. expansum produced at 0.900 a w germinated respectively up to 8h and 3h earlier than conidia produced at 0.980 a w . Furthermore, trehalose and mannitol assessments suggested that earlier germination might be related to delayed conidial maturation even though no ultra-structural modifications were observed by transmission electron microscopy. Taken together, these results highlight the importance of considering environmental conditions during sporulation in mycological studies. The physiological state of fungal conidia should be taken into account to design challenge tests or predictive mycology studies. This knowledge may also be of interest to improve the germination capacity of fungal cultures commonly used in fermented foods.

      PubDate: 2016-10-27T21:43:47Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.022
      Issue No: Vol. 241 (2016)
       
  • Pineapple (Ananas comosus L. Merr.) wine production in Angola:
           Characterisation of volatile aroma compounds and yeast native flora
    • Authors: Eduardo Dellacassa; Oriol Trenchs; Laura Fariña; Florencia Debernardis; Gabriel Perez; Eduardo Boido; Francisco Carrau
      Pages: 161 - 167
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Eduardo Dellacassa, Oriol Trenchs, Laura Fariña, Florencia Debernardis, Gabriel Perez, Eduardo Boido, Francisco Carrau
      A pineapple vinification process was conducted through inoculated and spontaneous fermentation to develop a process suitable for a quality beverage during two successive vintages in Huambo, Angola. Wines obtained with the conventional Saccharomyces cerevisiae strain, were analysed by gas chromatography, and a total of 61 volatile constituents were detected in the volatile fraction and 18 as glycosidically bound aroma compounds. Concentration levels of carbonyl and sulphur compounds were in agreement with the limited information reported about pineapple fruits of other regions. We report, for the first time in pineapple wines, the presence of significant concentrations of lactones, ketones, terpenes, norisoprenoids and a variety of volatile phenols. Eight native yeast strains were isolated from spontaneous batches. Further single-strain fermentations allowed us to characterise their suitability for commercial fermentation. Three native strains (Hanseniaspora opuntiae, H. uvarum and Meyerozyma guilliermondii) were selected with sensory potential to ferment pineapple fruits with increased flavour diversity. Results obtained here contribute to a better understanding of quality fermentation alternatives of this tropical fruit in subtropical regions.

      PubDate: 2016-10-27T21:43:47Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.014
      Issue No: Vol. 241 (2016)
       
  • Detection and genome characterization of bovine polyomaviruses in beef
           muscle and ground beef samples from Germany
    • Authors: Donina Gräfe; Bernhard Ehlers; Dietrich Mäde; Lüppo Ellerbroek; Tassilo Seidler; Reimar Johne
      Pages: 168 - 172
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Donina Gräfe, Bernhard Ehlers, Dietrich Mäde, Lüppo Ellerbroek, Tassilo Seidler, Reimar Johne
      Polyomaviruses are small, non-enveloped, circular double-stranded DNA viruses. Some polyomaviruses can induce tumors and cancer under certain circumstances. The bovine polyomaviruses (BPyV) 1–3 have been only scarcely analyzed so far. It was hypothesized that the consumption of beef meat containing polyomaviruses could contribute to the development of cancer in humans. In order to assess the distribution of the BPyV genome in meat from Germany, 101 beef muscle samples and 10 ground beef samples were analyzed here. A specific sample preparation method combined with or without rolling circle amplification (RCA), and BPyV-specific PCRs were developed and applied. BPyV-1 DNA was detected in 1/101 (1%) samples from beef meat and in 2/10 (20%) ground beef samples. BPyV-2 DNA was detected in 3/10 (30%) ground beef samples, whereas BPyV-3 was not detected in the samples. Application of RCA did not increase the detection rate in ground beef samples. Sequence analysis of the PCR products indicated the presence of BPyV-1, BPyV-2a and BPyV-2b. The whole genome of a BPyV-1 strain from ground beef meat showed 97.8% sequence identity to the BPyV-1 reference strain and that of a BPyV-2a strain from ground beef meet showed 99.9% sequence identity to strain 2aS11. It can be concluded that BPyV genomes can be frequently detected in ground beef samples, although higher sample numbers should be investigated in future to confirm this finding. Further studies should focus on the infectivity, tumorigenicity and heat resistance of the contained viruses in order to assess the risk of cancer induction through consumption of BPyVs present in beef products.

      PubDate: 2016-10-27T21:43:47Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.024
      Issue No: Vol. 241 (2016)
       
  • Isolation and characterization of Lactobacillus helveticus DSM 20075
           variants with improved autolytic capacity
    • Authors: Maciej Spus; Hua Liu; Michiel Wels; Tjakko Abee; Eddy J. Smid
      Pages: 173 - 180
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Maciej Spus, Hua Liu, Michiel Wels, Tjakko Abee, Eddy J. Smid
      Lactobacillus helveticus is widely used in dairy fermentations and produces a range of enzymes, which upon cell lysis can be released into the cheese matrix and impact degradation of proteins, peptides and lipids. In our study we set out to explore the potential of Lb. helveticus DSM 20075 for increased autolytic capacity triggered by conditions such as low pH and high salt concentrations encountered in cheese environments. Lb. helveticus DSM 20075 was subjected to varied incubation temperatures (ranging from 37 to 50°C). High-temperature incubation (in the range of 45 to 50°C) allowed us to obtain a collection of six variant strains (V45-V50), which in comparison to the wild-type strain, showed higher growth rates at elevated temperatures (42°C–45°C). Moreover, variant strain V50 showed a 4-fold higher, in comparison to wild type, autolytic capacity in cheese-like conditions. Next, strain V50 was used as an adjunct in lab-scale cheese making trials to measure its impact on aroma formation during ripening. Specifically, in cheeses made with strain V50, the relative abundance of benzaldehyde increased 3-fold compared to cheeses made with the wild-type strain. Analysis of the genome sequence of strain V50 revealed multiple mutations in comparison to the wild-type strain DSM 20075 including a mutation found in a gene coding for a metal ion transporter, which can potentially be linked to intracellular accumulation of Mn2+ and benzaldehyde formation. The approach of high-temperature incubation can be applied in dairy industry for the selection of (adjunct) cultures targeted at accelerated cheese ripening and aroma formation.

      PubDate: 2016-10-27T21:43:47Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.020
      Issue No: Vol. 241 (2016)
       
  • Influence of physical and chemical characteristics of wine grapes on the
           incidence of Penicillium and Aspergillus fungi in grapes and ochratoxin A
           in wines
    • Authors: Luísa Freire; Fabiana Reinis Franca Passamani; Ariela Betsy Thomas; Rita de Cássia Mirela Resende Nassur; Lais Mesquita Silva; Fabiano Narciso Paschoal; Giuliano Elias Pereira; Guilherme Prado; Luís Roberto Batista
      Pages: 181 - 190
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Luísa Freire, Fabiana Reinis Franca Passamani, Ariela Betsy Thomas, Rita de Cássia Mirela Resende Nassur, Lais Mesquita Silva, Fabiano Narciso Paschoal, Giuliano Elias Pereira, Guilherme Prado, Luís Roberto Batista
      The incidence of filamentous fungi and toxin levels in grapes and wines varies depending on the variety of grapes, the wine region, agricultural practices, weather conditions, the harvest and the winemaking process. In this sense, the objective of this study was to evaluate the diversity of Aspergillus and Penicillium fungi isolated from wine grapes of the semi-arid tropical region of Brazil, evaluate the presence of ochratoxin A (OTA) in the experimental wine and verify if there is a correlation between occurrence of these fungi and the physicochemical characteristics of the wine grapes grown in the region. For the isolation of fungi we used the direct plating technique. The presence of OTA in the experimental wine was detected by high-performance liquid chromatography. The species found were Aspergillus niger, A. carbonarius, A. aculeatus, A. niger Aggregate, A. flavus, A. sojae, Penicillium sclerotiorum, P. citrinum, P. glabrum, P. decumbens, P. solitum and P. implicatum. All isolates of A. carbonarius were OTA producers and all P. citrinum were citrinin producers. The highest concentration of OTA was found in red wine (0.29μg/L). All species identified in this study, except A. flavus, showed a positive correlation with at least one physicochemical parameter assessed, highlighting the pectin content, total sugar, total acidity and phenolic compounds.

      PubDate: 2016-10-27T21:43:47Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.027
      Issue No: Vol. 241 (2016)
       
  • Diversity of spoilage fungi associated with various French dairy products
    • Authors: Lucille Garnier; Florence Valence; Audrey Pawtowski; Lizaveta Auhustsinava-Galerne; Nicolas Frotté; Riccardo Baroncelli; Franck Deniel; Emmanuel Coton; Jérôme Mounier
      Pages: 191 - 197
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Lucille Garnier, Florence Valence, Audrey Pawtowski, Lizaveta Auhustsinava-Galerne, Nicolas Frotté, Riccardo Baroncelli, Franck Deniel, Emmanuel Coton, Jérôme Mounier
      Yeasts and molds are responsible for dairy product spoilage, resulting in significant food waste and economic losses. Yet, few studies have investigated the diversity of spoilage fungi encountered in dairy products. In the present study, 175 isolates corresponding to 105 from various spoiled dairy products and 70 originating from dairy production environments, were identified using sequencing of the ITS region, the partial β-tubulin, calmodulin and/or EFα genes, and the D1–D2 domain of the 26S rRNA gene for filamentous fungi and yeasts, respectively. Among the 41 species found in spoiled products, Penicillium commune and Penicillium bialowiezense were the most common filamentous fungi, representing around 10% each of total isolates while Meyerozyma guilliermondii and Trichosporon asahii were the most common yeasts (4.8% each of total isolates). Several species (e.g. Penicillium antarcticum, Penicillium salamii and Cladosporium phyllophilum) were identified for the first time in dairy products or their environment. In addition, numerous species were identified in both spoiled products and their corresponding dairy production environment suggesting that the latter acts as a primary source of contamination. Secondly, the resistance to chemical preservatives (sodium benzoate, calcium propionate, potassium sorbate and natamycin) of 10 fungal isolates representative of the observed biodiversity was also evaluated. Independently of the fungal species, natamycin had the lowest minimum inhibitory concentration (expressed in gram of preservative/l), followed by potassium sorbate, sodium benzoate and calcium propionate. In the tested conditions, Cladosporium halotolerans and Didymella pinodella were the most sensitive fungi while Yarrowia lipolytica and Candida parapsilosis were the most resistant towards the tested preservatives. This study provides interesting information on the occurrence of fungal contaminants in dairy products and environments that may help developing adequate strategies for fungal spoilage control.

      PubDate: 2016-10-27T21:43:47Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.026
      Issue No: Vol. 241 (2016)
       
  • Oxidative stress in E. coli cells upon exposure to heat treatments
    • Authors: María Marcén; Virginia Ruiz; Mª Jesús Serrano; Santiago Condón; Pilar Mañas
      Pages: 198 - 205
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): María Marcén, Virginia Ruiz, Mª Jesús Serrano, Santiago Condón, Pilar Mañas
      Heat treatments are widely used by the food industry to inactivate microorganisms, however their mode of action on microbial cells is not fully known. In the last years, it has been proposed that the generation of oxidative species could be an important factor contributing to cell death by heat and by other stresses; however, investigations in this field are scarce. The present work studies the generation of reactive oxygen species (ROS) upon heat treatment in E. coli, through the use of cell staining with specific fluorochromes. Results obtained demonstrate that ROS are detected in E. coli cells when they are subjected to heat exposure, and the amount of fluorescence increases with temperature and time, as does the cellular inactivation. The addition of glutathione or tiron, a potent antioxidant and a superoxide quencher, respectively, to the heating medium protected E. coli against heat inactivation and concurrently reduced the detection of ROS, especially in the case of glutathione. Finally, recovery of heated cells under conditions that relief oxidative stress produced an increase in cell survival. Data presented in this work support the view that ROS generation and subsequent control in bacterial cells could be an essential factor determining inactivation and survival upon exposure to heat, and it could be a potential target to increase the efficacy of current treatments.

      PubDate: 2016-10-27T21:43:47Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.023
      Issue No: Vol. 241 (2016)
       
  • Cross-protection between controlled acid-adaptation and thermal
           inactivation for 48 Escherichia coli strains
    • Authors: Leticia Ungaretti Haberbeck; Xiang Wang; Chris Michiels; Frank Devlieghere; Mieke Uyttendaele; Annemie H. Geeraerd
      Pages: 206 - 214
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Leticia Ungaretti Haberbeck, Xiang Wang, Chris Michiels, Frank Devlieghere, Mieke Uyttendaele, Annemie H. Geeraerd
      Given the importance of pH reduction and thermal treatment in food processing and food preservation strategies, the cross-protection between acid adaptation and subsequent thermal inactivation for 48 Escherichia coli strains was investigated. Those strains were selected among 188 E. coli strains according to their odds of growth under low pH conditions as determined by Haberbeck et al. (2015) [Haberbeck, L.U., Oliveira, R.C., Vivijs, B., Wenseleers, T., Aertsen, A., Michiels, C., Geeraerd, A.H., 2015. Variability in growth/no growth boundaries of 188 different Escherichia coli strains reveals that approximately 75% have a higher growth probability under low pH conditions than E. coli O157:H7 strain ATCC 43888. Food Microbiol. 45, 222–230]. E. coli cells were acid and nonacid-adapted during overnight growth in controlled acidic pH (5.5) and neutral pH (7.0), respectively, in buffered Lysogenic Broth (LB). Then, they were heat inactivated at 58°C in non-buffered LB adjusted to pH6.2 and 7.0. Thus, four conditions were tested in total by combining the different pH values during growth/thermal inactivation: 5.5/6.2, 5.5/7.0, 7.0/6.2 and 7.0/7.0. Acid adaptation in buffered LB at pH5.5 increased the heat resistance of E. coli strains in comparison with nonacid-adaptation at pH7.0. For instance, the median D 58 -value of strains inactivated at pH7.0 was approximately 6 and 4min for acid-adapted and nonacid-adapted strains, respectively. For the nonacid-adapted strains, the thermal inactivation at pH6.2 and 7.0 was not significantly (p =0.06) different, while for the acid-adapted strains, the thermal treatment at pH6.2 showed a higher heat resistance than at pH7.0. The correlation between the odds of growth under low pH previously determined and the heat resistance was significant (p <0.05). Remarkably, a great variability in heat resistance among the strains was observed for all pH combinations, with D 58 -values varying between 1.0 and 69.0min. In addition, highly heat resistant strains were detected. Those strains exhibited D 58 -values between 17.6 and 69.0min, while E. coli O157:H7 (ATCC 43888) showed D 58 -values between 1.2 and 3.1min. In summary, results clearly showed that adaptation of E. coli cells to constant acidic pH results in cross-protection against thermal inactivation.

      PubDate: 2016-10-27T21:43:47Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.006
      Issue No: Vol. 241 (2016)
       
  • Tolerance to quaternary ammonium compound disinfectants may enhance growth
           of Listeria monocytogenes in the food industry
    • Authors: Trond Møretrø; Bjørn C.T. Schirmer; Even Heir; Annette Fagerlund; Pernille Hjemli; Solveig Langsrud
      Pages: 215 - 224
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Trond Møretrø, Bjørn C.T. Schirmer, Even Heir, Annette Fagerlund, Pernille Hjemli, Solveig Langsrud
      The antibacterial effect of disinfectants is crucial for the control of Listeria monocytogenes in food processing environments. Tolerance of L. monocytogenes to sublethal levels of disinfectants based on quaternary ammonium compounds (QAC) is conferred by the resistance determinants qacH and bcrABC. The presence and distribution of these genes have been anticipated to have a role in the survival and growth of L. monocytogenes in food processing environments where QAC based disinfectants are in common use. In this study, a panel of 680 L. monocytogenes from nine Norwegian meat- and salmon processing plants were grouped into 36 MLVA profiles. The presence of qacH and bcrABC was determined in 101 isolates from the 26 most common MLVA profiles. Five MLVA profiles contained qacH and two contained bcrABC. Isolates with qacH and bcrABC showed increased tolerance to the QAC Benzalkonium chloride (BC), with minimal inhibitory concentrations (MICs) of 5–12, 10–13 and <5ppm for strains with qacH (two allele variants observed), bcrABC, and neither gene, respectively. Isolates with qacH or bcrABC were not more tolerant to BC in bactericidal tests in suspension or in biofilms compared with isolates lacking the genes. Water residue samples collected from surfaces in meat processing plants after QAC disinfection had bactericidal effect against L. monocytogenes when the sample BC levels were high (>100ppm). A sample with lower BC concentrations (14ppm of chain length C-12 and 2.7ppm of chain length C-14) inhibited growth of L. monocytogenes not containing bcrABC or qacH, compared to strains with these genes. The study has shown that L. monocytogenes harbouring the QAC resistance genes qacH and bcrABC are prevalent in the food industry and that residuals of QAC may be present in concentrations after sanitation in the industry that result in a growth advantage for bacteria with such resistance genes.

      PubDate: 2016-10-27T21:43:47Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.025
      Issue No: Vol. 241 (2016)
       
  • Lactate- and acetate-based cross-feeding interactions between selected
           strains of lactobacilli, bifidobacteria and colon bacteria in the presence
           of inulin-type fructans
    • Authors: Frédéric Moens; Marko Verce; Luc De Vuyst
      Pages: 225 - 236
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Frédéric Moens, Marko Verce, Luc De Vuyst
      Cross-feeding interactions were studied between selected strains of lactobacilli and/or bifidobacteria and butyrate-producing colon bacteria that consume lactate but are not able to degrade inulin-type fructans (ITF) in a medium for colon bacteria (supplemented with ITF as energy source and acetate when necessary). Degradation of oligofructose by Lactobacillus acidophilus IBB 801 and inulin by Lactobacillus paracasei 8700:2 and Bifidobacterium longum LMG 11047 resulted in the release of free fructose into the medium and the production of mainly lactate (lactobacilli) and acetate (B. longum LMG 11047). During bicultures of Lb. acidophilus IBB 801 and Anaerostipes caccae DSM 14662T on oligofructose, the latter strain converted lactate (produced by the former strain from oligofructose) into butyrate and gases, but only in the presence of acetate. During bicultures of Lb. paracasei 8700:2 and A. caccae DSM 14662T or Eubacterium hallii DSM 17630 on inulin, the butyrate-producing strains consumed low concentrations of lactate and acetate generated by inulin degradation by the Lactobacillus strain. As more acetate was produced during tricultures of Lb. paracasei 8700:2 and B. longum LMG 11047, which degraded inulin simultaneously, and A. caccae DSM 14662T or E. hallii DSM 17630, a complete conversion of lactate into butyrate and gases by these butyrate-producing strains occurred. Therefore, butyrate production by lactate-consuming, butyrate-producing colon bacterial strains incapable of ITF degradation, resulted from cross-feeding of monosaccharides and lactate by an ITF-degrading Lactobacillus strain and acetate produced by a Bifidobacterium strain.

      PubDate: 2016-10-27T21:43:47Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.019
      Issue No: Vol. 241 (2016)
       
  • F-coliphages, porcine adenovirus and porcine teschovirus as potential
           indicator viruses of fecal contamination for pork carcass processing
    • Authors: Tineke H. Jones; Victoria Muehlhauser
      Pages: 237 - 243
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Tineke H. Jones, Victoria Muehlhauser
      There are concerns about the zoonotic transmission of viruses through undercooked pork products. There is a lack of information on suitable indicator viruses for fecal contamination with pathogenic enteric viruses in the meat processing chain. The study compared the incidence and levels of contamination of hog carcasses with F-coliphages, porcine teschovirus (PTV), and porcine adenovirus (PAdV) at different stages of the dressing process to assess their potential as indicator viruses of fecal contamination. One hundred swab samples (200cm2) were collected from random sites on hog carcasses at 4 different stages of the dressing process and from retail pork over the span of a year from 2 pork processing plants (500/plant). Viable F-coliphages, PAdV DNA and PTV RNA were each detected on ≥99% of the incoming carcasses at both plants and were traceable through the pork processing chain. Significant correlations were observed between viable F-coliphages and PAdV DNA and between F-coliphages and PTV RNA but not between PAdV DNA and PTV RNA at the various stages of pork processing. Detection of viable F-coliphages was more sensitive than genomic copies of PAdV and PTV at low levels of contamination, making F-coliphages a preferred indicator in the pork slaughter process as it also provides an indication of infectivity. For plant A, F-RNA coliphages were detected in 25%, 63%, and 21% of carcass swabs after pasteurization, evisceration, and retail pork products, respectively. For plant B, F-coliphages were detected in 33%, 25%, and 13% of carcass swabs after skinning, evisceration, and retail pork samples, respectively. Viable F-RNA coliphages were genotyped. Viable F-RNA GII and GIII were generally not detected at the earlier stages of the slaughter process but they were detected on 13% of carcasses after evisceration and 2% of retail pork samples at plant A, which raises concerns of potential food handler contamination during pork processing. Consumers could be at risk when consuming undercooked meat contaminated with pathogenic enteric viruses.

      PubDate: 2016-11-03T10:18:57Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.032
      Issue No: Vol. 241 (2016)
       
  • Aspergillus westerdijkiae as a major ochratoxin A risk in dry-cured ham
           based-media
    • Authors: Ziva Vipotnik; Alicia Rodríguez; Paula Rodrigues
      Pages: 244 - 251
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Ziva Vipotnik, Alicia Rodríguez, Paula Rodrigues
      Penicillium nordicum is well known for its ability to produce high amounts of ochratoxin A (OTA) in cured meat-derived products. On the other hand, Aspergillus westerdijkiae, one of the most relevant OTA-producing species of the genus Aspergillus, is usually considered a major risk in carbon-rich food matrices of plant origin. The objective of this work was to evaluate, for the first time, the ecophysiological conditions governing growth, OTA production and sporulation of A. westerdijkiae (the type-strain and one ham-native strain), in comparison with P. nordicum, in dry-cured ham based medium. For that purpose, the interaction between temperature (15, 20, 25 and 30°C) and water activity (aw) (0.99, 0.97, 0.93, 0.90 and 0.85), achieved with a combination of ionic (NaCl) and non-ionic (glycerol) solutes, was studied by using dry-cured ham-based medium as a model system. Different OTA production profiles were found between the two genera, and also between the two strains of A. westerdijkiae, mostly in terms of amounts of OTA produced. The optimal OTA production conditions for A. westerdijkiae were at 0.94–0.97 aw and 20–25°C, and for P. nordicum at 0.95–0.97 aw between 18 and 22°C. Under these conditions, A. westerdijkiae produced 1934ng/g agar, while P. nordicum produced 712ng/g. None of the strains was able to produce detectable amounts of OTA at 0.85 aw, under all temperatures tested. Growth and sporulation were not good indicators of OTA production by A. westerdijkiae or P. nordicum. The results obtained show that A. westerdijkiae may represent a great potential risk of OTA contamination in dry-cured ham due to the high production under a wide range of conditions. Knowledge of the ecophysiology of important Aspergillus and Penicillium species and of their adaptability to the matrices can be determinant to adopt appropriate technological modifications during ham ripening process.

      PubDate: 2016-11-03T10:18:57Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.031
      Issue No: Vol. 241 (2016)
       
  • Improving the antioxidant properties of quinoa flour through fermentation
           with selected autochthonous lactic acid bacteria
    • Authors: Carlo Giuseppe Rizzello; Anna Lorusso; Vito Russo; Daniela Pinto; Barbara Marzani; Marco Gobbetti
      Pages: 252 - 261
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Carlo Giuseppe Rizzello, Anna Lorusso, Vito Russo, Daniela Pinto, Barbara Marzani, Marco Gobbetti
      Lactic acid bacteria strains, previously isolated from the same matrix, were used to ferment quinoa flour aiming at exploiting the antioxidant potential. As in vitro determined on DPPH and ABTS radicals, the scavenging activity of water/salt-soluble extracts (WSE) from fermented doughs was significantly (P <0.05) higher than that of non-inoculated doughs. The highest inhibition of linoleic acid autoxidation was found for the quinoa dough fermented with Lactobacillus plantarum T0A10. The corresponding WSE was subjected to Reverse Phase Fast Protein Liquid Chromatography, and 32 fractions were collected and subjected to in vitro assays. The most active fraction was resistant to further hydrolysis by digestive enzymes. Five peptides, having sizes from 5 to 9 amino acid residues, were identified by nano-Liquid Chromatography-Electrospray Ionisation-Mass Spectra/Mass Spectra. The sequences shared compositional features which are typical of antioxidant peptides. As shown by determining cell viability and radical scavenging activity (MTT and DCFH-DA assays, respectively), the purified fraction showed antioxidant activity on human keratinocytes NCTC 2544 artificially subjected to oxidative stress. This study demonstrated the capacity of autochthonous lactic acid bacteria to release peptides with antioxidant activity through proteolysis of native quinoa proteins. Fermentation of the quinoa flour with a selected starter might be considered suitable for novel applications as functional food ingredient, dietary supplement or pharmaceutical preparations.

      PubDate: 2016-11-03T10:18:57Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.035
      Issue No: Vol. 241 (2016)
       
  • Parasite to patient: A quantitative risk model for Trichinella spp. in
           pork and wild boar meat
    • Authors: Frits Franssen; Arno Swart; Joke van der Giessen; Arie Havelaar; Katsuhisa Takumi
      Pages: 262 - 275
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Frits Franssen, Arno Swart, Joke van der Giessen, Arie Havelaar, Katsuhisa Takumi
      Consumption of raw or inadequately cooked pork meat may result in trichinellosis, a human disease due to nematodes of the genus Trichinella. In many countries worldwide, individual control of pig carcasses at meat inspection is mandatory but incurs high costs in relation to absence of positive carcasses from pigs reared under controlled housing. EU regulation 2015/1375 implements an alternative risk-based approach, in view of absence of positive findings in pigs under controlled housing conditions. Moreover, Codex Alimentarius guidelines for the control of Trichinella spp. in meat of suidae have been published (CAC, 2015) and used in conjunction with the OIE terrestrial Animal health code, to provide guidance to governments and industry on risk based control measures to prevent human exposure to Trichinella spp. and to facilitate international pork trade. To further support such a risk-based approach, we model the risk of human trichinellosis due to consumption of meat from infected pigs, raised under non-controlled housing and wild boar, using Quantitative Microbial Risk Assessment (QMRA) methods. Our model quantifies the distribution of Trichinella muscle larve (ML) in swine, test sensitivity at carcass control, partitioning of edible pork parts, Trichinella ML distribution in edible muscle types, heat inactivation by cooking and portion sizes. The resulting exposure estimate is combined with a dose response model for Trichinella species to estimate the incidence of human illness after consumption of infected meat. Paramater estimation is based on experimental and observational datasets. In Poland, which served as example, we estimated an average incidence of 0.90 (95%CI: 0.00–3.68) trichinellosis cases per million persons per year (Mpy) due to consumption of pork from pigs that were reared under non-controlled housing, and 1.97 (95%CI: 0.82–4.00) cases per Mpy due to consumption of wild boar. The total estimated incidence of human trichinellosis attributed to pigs from non-controlled housing and wild boar in Poland, is similar to the incidence of human trichinellosis in that country reported by EFSA. Overall, in Europe, we estimated an upper incidence limit of 5.3×10−4 cases per Mpy, or less than one predicted case of trichinellosis in the European Union every 4years, due to consumption of pork from controlled housing. Therefore, Trichinella testing of pigs under controlled housing is not adding any value to protect human health. We suggest applying our farm-to-fork QMRA model to further support decision making on the global scale.

      PubDate: 2016-11-10T11:46:07Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.029
      Issue No: Vol. 241 (2016)
       
  • Combined effect of antagonistic yeast and modified atmosphere to control
           Penicillium expansum infection in sweet cherries cv. Ambrunés
    • Authors: E. de Paiva; M.J. Serradilla; S. Ruiz-Moyano; M.G. Córdoba; M.C. Villalobos; R. Casquete; A. Hernández
      Pages: 276 - 282
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): E. de Paiva, M.J. Serradilla, S. Ruiz-Moyano, M.G. Córdoba, M.C. Villalobos, R. Casquete, A. Hernández
      Fruit decay caused by pathogenic moulds is a major concern in the postharvest quality and shelf life of fruit. Blue mould decay is caused by Penicillium expansum (P. expansum) and is one of the most important postharvest diseases in cherries (Prunus avium L.). Synthetic fungicides are the main medium used to control pathogenic moulds. However, alternative approaches are available for developing safer technologies to control postharvest disease. An integrated approach that combines biological control, using antagonistic yeasts and modified atmosphere packaging (MAP) with cold storage is a promising alternative to synthetic fungicide treatment. In this work, two microperforated films (M10 and M50) and two antagonistic yeast strains (Hanseniaspora opuntiae L479 and Metschnikowia pulcherrima L672) were evaluated for their effectiveness to control the development of P. expansum in wounded cherries stored at 1°C. Results showed that the microperforated films had fungistatic effects, particularly M50, due to the level of CO2 achieved (mean CO2 of 11.2kPa at 35days), and the decrease in disease severity. Antagonistic yeasts, particularly Metschnikowia pulcherrima L672, delayed the development of P. expansum and decreased disease incidence and severity. The combination of MAP and antagonistic yeasts was the most effective approach to control P. expansum, during cold storage.

      PubDate: 2016-11-10T11:46:07Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.033
      Issue No: Vol. 241 (2016)
       
  • Evaluation of meat, fruit and vegetables from retail stores in five United
           Kingdom regions as sources of extended-spectrum beta-lactamase
           (ESBL)-producing and carbapenem-resistant Escherichia coli
    • Authors: L.P. Randall; M.P Lodge; N.C. Elviss; F.L. Lemma; K.L. Hopkins; C.J. Teale; N. Woodford
      Pages: 283 - 290
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): L.P. Randall, M.P Lodge, N.C. Elviss, F.L. Lemma, K.L. Hopkins, C.J. Teale, N. Woodford
      We determined the prevalence and types of extended-spectrum β-lactamase (ESBL)-producing and carbapenem-resistant Escherichia coli in raw retail beef, chicken, pork, fruit and vegetables in five UK regions in 2013–14. Raw meat (n=397), and fruit and vegetable samples (n=400) were purchased from retail stores in London, East Anglia, North West England, Scotland and Wales. Samples were tested for the presence of ESBL-producing E. coli by plating enriched samples on CHROMagar CTX and CHROMagar ESBL, for AmpC-type E. coli by plating on “CHROMagar FOX” (CHROMagar ECC+16mg/L cefoxitin), and for carbapenem-resistant E. coli by plating on CHROMagar KPC. Additionally, pre-enrichment counts were performed on the above agars, and on CHROMagar ECC. Isolates of interest were characterised by MALDI-ToF to confirm identification, by PCR for bla CIT, bla CTX-M, bla OXA, bla SHV and bla TEM genes; ESBL or bla CIT genes were sequenced. Only 1.9% and 2.5% of beef and pork samples, respectively were positive for ESBL-producing E. coli after enrichment compared with 65.4% of chicken samples. 85.6% positive samples from chicken meat carried bla CTX-M-1; bla CTX-M-15 was not detected. None of the fruits or vegetables yielded ESBL-producing E. coli and none of the meat, fruit or vegetable samples yielded carbapenem-resistant E. coli. Retail chicken was more frequently a source of ESBL-producing E. coli than were beef, pork, fruit or vegetables. None of the foodstuffs yielded E. coli with CTX-M-15 ESBL, which dominates in human clinical isolates in the UK, and none yielded carbapenem-resistant E. coli.

      PubDate: 2016-11-10T11:46:07Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.036
      Issue No: Vol. 241 (2016)
       
  • Characterization of three autolysins with activity against
           cereulide-producing Bacillus isolates in food matrices
    • Authors: Peiling Geng; Yimin Hu; Guoping Zhou; Zhiming Yuan; Xiaomin Hu
      Pages: 291 - 297
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Peiling Geng, Yimin Hu, Guoping Zhou, Zhiming Yuan, Xiaomin Hu
      Bacillus cereus is a pathogen related with diarrhoeal or emetic food poisoning cases, of which the latter caused by the cereulide-producing isolates are more severe with several reported lethal cases. It is therefore necessary to develop an effective strategy to prevent the propagation of B. cereus in the food supply. In this study, three autolysins from the cereulide-producing B. cereus group isolates, LysIS075, LysF8819.1 and LysCER057, were identified and characterized. The results showed that the three autolysins were highly lytic and bactericidal to the tested cereulide-producing B. cereus group strains and cross-lytic against other tested B. cereus group strains, and they could inhibit the spore germination and propagation of their tested derived emetic strains. Physical and chemical characterization showed that all the three autolysins were alkalophilic with the optimal activity at pH9.0 or 9.5 with one exception of LysF8819.1 also having significant lytic activity at pH5.0, and they all had relative strong lytic activity at 37–50°C during the 30minute assay. However, LysCER057 showed relative susceptibility to thermo-condition. Remarkably, the separate or cock-tail addition of the three autolysins in food matrices (milk and rice porridge) showed effective bactericidal activity within the tested 2h. All the results revealed that the three autolysins might be potential candidates to control emetic B. cereus strains in different applications.

      PubDate: 2016-11-10T11:46:07Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.030
      Issue No: Vol. 241 (2016)
       
  • Microbiota of high-pressure-processed Serrano ham investigated by
           culture-dependent and culture-independent methods
    • Authors: N. Martínez-Onandi; A. Castioni; E. San Martín; A. Rivas-Cañedo; M. Nuñez; S. Torriani; A. Picon
      Pages: 298 - 307
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): N. Martínez-Onandi, A. Castioni, E. San Martín, A. Rivas-Cañedo, M. Nuñez, S. Torriani, A. Picon
      The microbiota of Serrano dry-cured ham of different chemical composition, subjected or not to high-pressure processing (HPP), was investigated using culture-dependent and culture-independent methods. Microbial counts were submitted to analysis of variance with physicochemical parameters (aw, NaCl concentration, salt-in-lean ratio and intramuscular fat content) or HPP as main effects. In untreated hams, physicochemical parameters significantly affected counts of aerobic mesophiles, psychrotrophs, and moulds and yeasts. NaCl concentration and fat content influenced the levels of four and three of the five studied microbial groups, respectively, whereas no influence of aw was stated. The HPP treatment had a significant effect on counts of all investigated microbial groups. Culture-independent methods showed the presence of bacteria such as Staphylococcus equorum, Staphylococcus succinus, Bacillus subtilis and Cellulosimicrobium sp., moulds like Penicillium commune, Aspergillus fumigatus, Sclerotinia sclerotiorum, Eurotium athecium and Moniliella mellis, and yeasts like Debaryomyces hansenii and Candida glucosophila. Absence of B. subtilis bands and weaker bands of E. athecium were recorded for HPP-treated hams. The higher microbial levels found in lean ham might result in a quicker deterioration. HPP treatment confirmed its suitability as a procedure to control spoilage microorganisms. DGGE did not seem to be sensitive enough to highlight changes caused by HPP treatment in the microbiota of ham, but contributed to the detection of microbial species not previously found in ham.

      PubDate: 2016-11-10T11:46:07Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.001
      Issue No: Vol. 241 (2016)
       
  • Whey powders are a rich source and excellent storage matrix for dairy
           bacteriophages
    • Authors: Natalia Wagner; Erik Brinks; Meike Samtlebe; Jörg Hinrichs; Zeynep Atamer; Witold Kot; Charles M.A.P. Franz; Horst Neve; Knut J. Heller
      Pages: 308 - 317
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Natalia Wagner, Erik Brinks, Meike Samtlebe, Jörg Hinrichs, Zeynep Atamer, Witold Kot, Charles M.A.P. Franz, Horst Neve, Knut J. Heller
      Thirteen whey powders and 5 whey powder formulations were screened for the presence of dairy bacteriophages using a representative set of 8 acid-producing Lactococcus lactis and 5 Streptococcus thermophilus, and 8 flavour-producing Leuconostoc pseudomesenteroides and Leuconostoc mesenteroides strains. Lytic L. lactis phages were detected in all samples, while S. thermophilus and Leuconostoc phages were present in 50% or 40% of the samples, respectively. Maximal phage titers were 6×107 plaque-forming units (pfu)/g of whey powder for L. lactis phages, 1×107 pfu/g for Leuconostoc phages and 1×105 pfu/g for S. thermophilus phages. In total, 55 phages were isolated and characterized. Thirty one of the 33 lactococcal phages tested belonged to the wide-spread 936 phage group. In the course of this study, a PCR detection method for Leuconostoc phages (Ali et al., 2013) was adapted to new phage isolates. Furthermore, a remarkably high stability of phages in whey powder samples was documented during a long-term storage period of 4 years.

      PubDate: 2016-11-10T11:46:07Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.037
      Issue No: Vol. 241 (2016)
       
  • Risk factors for norovirus contamination of shellfish water catchments in
           England and Wales
    • Authors: Carlos J.A. Campos; Simon Kershaw; Owen C. Morgan; David N. Lees
      Pages: 318 - 324
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Carlos J.A. Campos, Simon Kershaw, Owen C. Morgan, David N. Lees
      This study examines the relationships between concentrations of human noroviruses (NoV) genogroups I (GI) and II (GII) and Escherichia coli monitored in oysters from 31 commercial harvesting areas on the coast of England and Wales from May 2009 to April 2011 and demographic, hydrometric, climatic and pollution source characteristics of upstream river catchments using multiple regression techniques. The predictive environmental factors for E. coli contamination in the oysters were rainfall (cumulative 7days before sampling) while the predictive factors for NoV (GI+GII) were water temperature, catchment area and the combined volume of continuous sewage discharges in the catchment. Oysters from cold waters (<5°C) had significantly higher NoV content than those from warmer waters (>10°C). The association with water temperature may be consequential on the seasonal prevalence of the virus in the community or linked with oyster metabolic function. In a group of 10 study sites, mean concentrations of NoV increased as the number of stormwater spills at those sites also increased. The results of this study could be used to evaluate the likely impact of sewerage infrastructure improvements in catchments at risk of NoV contamination and to help identify sites suitable for shellfish farming.

      PubDate: 2016-11-10T11:46:07Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.028
      Issue No: Vol. 241 (2016)
       
  • Deleting the citrinin biosynthesis-related gene, ctnE, to greatly reduce
           citrinin production in Monascus aurantiacus Li AS3.4384
    • Authors: Zhen-Qiang Ning; Hua Cui; Yang Xu; Zhi-Bing Huang; Zhui Tu; Yan-Ping Li
      Pages: 325 - 330
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): Zhen-Qiang Ning, Hua Cui, Yang Xu, Zhi-Bing Huang, Zhui Tu, Yan-Ping Li
      For thousands of years, fermentation products of the filamentous fungi Monascus spp. have been used extensively in the food and pharmaceutical industries. However, their development is limited because of the health threats from the mycotoxin citrinin, known to be produced by these fungi. Citrinin is recognized as a hepato-nephrotoxin which possesses potential genotoxicity, tumorigenicity, carcinogenicity, embryotoxicity, and teratogenicity. Studies have shown that citrinin biosynthesis is intimately related to pksCT, orf1, ctnA, orf3, ctnB and ctnG. The ctnE gene, which is located 3.3kb upstream of ctnA, encodes a protein that showed significant similarity to the dehydrogenase. In this study, the role of ctnE in citrinin biosynthesis was investigated by means of gene knockout technology. The ctnE disruptant significantly reduced citrinin production by 96%, which suggested that ctnE is important in citrinin biosynthesis. Moreover, the mutant produced 40% more pigments than the wild-type. This work contributes to the study of the citrinin biosynthesis pathway in Monascus, and the methodology described in this article can fundamentally lower the risk of citrinin contamination in Monascus aurantiacus Li AS3.4384 which has important significance for food safety.

      PubDate: 2016-11-17T08:07:01Z
      DOI: 10.1016/j.ijfoodmicro.2016.11.004
      Issue No: Vol. 241 (2016)
       
  • A chemometrics approach applied to Fourier transform infrared spectroscopy
           (FTIR) for monitoring the spoilage of fresh salmon (Salmo salar) stored
           under modified atmospheres
    • Authors: C. Saraiva; H. Vasconcelos; José M.M.M. de Almeida
      Pages: 331 - 339
      Abstract: Publication date: 16 January 2017
      Source:International Journal of Food Microbiology, Volume 241
      Author(s): C. Saraiva, H. Vasconcelos, José M.M.M. de Almeida
      The aim of this work was to investigate the potential of Fourier transform infrared spectroscopy (FTIR) to detect and predict the bacterial load of salmon fillets (Salmo salar) stored at 3, 8 and 30°C under three packaging conditions: air packaging (AP) and two modified atmospheres constituted by a mixture of 50%N2/40%CO2/10%O2 with lemon juice (MAPL) and without lemon juice (MAP). Fresh salmon samples were periodically examined for total viable counts (TVC), specific spoilage organisms (SSO) counts, pH, FTIR and sensory assessment of freshness. Principal components analysis (PCA) allowed identification of the wavenumbers potentially correlated with the spoilage process. Linear discriminant analysis (LDA) of infrared spectral data was performed to support sensory data and to accurately identify samples freshness. The effect of the packaging atmospheres was assessed by microbial enumeration and LDA was used to determine sample packaging from the measured infrared spectra. It was verified that modified atmospheres can decrease significantly the bacterial load of fresh salmon. Lemon juice combined with MAP showed a more pronounced delay in the growth of Brochothrix thermosphacta, Photobacterium phosphoreum, psychrotrophs and H2S producers. Partial least squares regression (PLS-R) allowed estimates of TVC and psychrotrophs, lactic acid bacteria, molds and yeasts, Brochothrix thermosphacta, Enterobacteriaceae, Pseudomonas spp. and H2S producer counts from the infrared spectral data. For TVC, the root mean square error of prediction (RMSEP) value was 0.78logcfug−1 for an external set of samples. According to the results, FTIR can be used as a reliable, accurate and fast method for real time freshness evaluation of salmon fillets stored under different temperatures and packaging atmospheres.

      PubDate: 2016-11-17T08:07:01Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.038
      Issue No: Vol. 241 (2016)
       
 
 
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