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  Subjects -> BIOLOGY (Total: 2974 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: 21)
Advances in Microbiology     Open Access   (Followers: 19)
Advances in Molecular Imaging     Open Access   (Followers: 1)
African Journal of Clinical and Experimental Microbiology     Open Access  
African Journal of Microbiology Research     Open Access   (Followers: 1)
Algorithms for Molecular Biology     Open Access   (Followers: 4)
American Journal of Infectious Diseases and Microbiology     Open Access   (Followers: 18)
American Journal of Microbiological Research     Open Access   (Followers: 2)
American Journal of Microbiology     Open Access   (Followers: 14)
American Journal of Molecular Biology     Open Access   (Followers: 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: 36)
Antimicrobial Agents and Chemotherapy     Hybrid Journal   (Followers: 22)
Antiviral Research     Hybrid Journal   (Followers: 7)
Applied and Environmental Microbiology     Hybrid Journal   (Followers: 43)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 17)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 61)
Aquatic Microbial Ecology     Hybrid Journal   (Followers: 3)
Archives of Microbiology     Hybrid Journal   (Followers: 8)
Avicenna Journal of Clinical Microbiology and Infection     Open Access   (Followers: 1)
Bangladesh Journal of Medical Microbiology     Open Access   (Followers: 1)
Beneficial Microbes     Full-text available via subscription   (Followers: 2)
Bio-Research     Full-text available via subscription   (Followers: 1)
BioArchitecture     Full-text available via subscription  
Bioethanol     Open Access  
Biomaterials Science     Full-text available via subscription   (Followers: 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   (Followers: 1)
BMC Microbiology     Open Access   (Followers: 10)
Brazilian Journal of Microbiology     Open Access   (Followers: 2)
Canadian Journal of Infectious Diseases and Medical Microbiology     Open Access   (Followers: 3)
Canadian Journal of Microbiology     Full-text available via subscription   (Followers: 4)
Cell Biology : Research & Therapy     Hybrid Journal   (Followers: 3)
Cell Host & Microbe     Full-text available via subscription   (Followers: 15)
Cell Medicine     Open Access   (Followers: 3)
Cell Regeneration     Open Access   (Followers: 1)
Cell Stem Cell     Full-text available via subscription   (Followers: 32)
CellBio     Open Access  
Cells     Open Access   (Followers: 2)
Cellular & Molecular Immunology     Hybrid Journal   (Followers: 12)
Cellular and Molecular Biology Letters     Open Access   (Followers: 1)
Cellular and Molecular Life Sciences (CMLS)     Hybrid Journal   (Followers: 7)
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: 20)
Clinical Microbiology Newsletter     Hybrid Journal   (Followers: 6)
Clinical Microbiology Reviews     Hybrid Journal   (Followers: 18)
Comparative Immunology, Microbiology and Infectious Diseases     Hybrid Journal   (Followers: 11)
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: 11)
Current Molecular Biology Reports     Hybrid Journal   (Followers: 1)
Current Molecular Imaging     Hybrid Journal  
Current Opinion in Microbiology     Hybrid Journal   (Followers: 30)
Current Tissue Engineering     Hybrid Journal   (Followers: 2)
Current Topics in Microbiology and Immunology     Hybrid Journal   (Followers: 11)
Diagnostic Microbiology and Infectious Disease     Hybrid Journal   (Followers: 8)
DNA Barcodes     Open Access  
Egyptian Journal of Biochemistry and Molecular Biology     Full-text available via subscription  
Emerging Microbes & Infections     Open Access   (Followers: 3)
Environmental Microbiology     Hybrid Journal   (Followers: 15)
Environmental Microbiology Reports     Hybrid Journal   (Followers: 4)
Enzyme and Microbial Technology     Hybrid Journal   (Followers: 14)
Epigenetics of Degenerative Diseases     Open Access   (Followers: 5)
European Journal of Clinical Microbiology & Infectious Diseases     Hybrid Journal   (Followers: 18)
European Journal of Microbiology and Immunology     Open Access   (Followers: 8)
Experimental and Molecular Pathology     Hybrid Journal   (Followers: 4)
Experimental Cell Research     Hybrid Journal   (Followers: 7)
Fems Microbiology Ecology     Hybrid Journal   (Followers: 8)
Fems Microbiology Letters     Hybrid Journal   (Followers: 19)
Fems Microbiology Reviews     Hybrid Journal   (Followers: 24)
Fermentation     Open Access   (Followers: 1)
Folia Histochemica et Cytobiologica     Open Access  
Folia Microbiologica     Hybrid Journal   (Followers: 1)
Food Microbiology     Hybrid Journal   (Followers: 16)
Frontiers in Cell and Developmental Biology     Open Access   (Followers: 3)
Frontiers in Cellular and Infection Microbiology     Open Access   (Followers: 3)
Frontiers in Cellular Neuroscience     Open Access   (Followers: 8)
Frontiers in Microbiology     Open Access   (Followers: 9)
Frontiers in Molecular Neuroscience     Open Access   (Followers: 4)
Future Microbiology     Hybrid Journal   (Followers: 4)
Future Virology     Hybrid Journal   (Followers: 7)
Gene Expression     Full-text available via subscription  
Genetica si Biologie Moleculara     Open Access  
Genetics and Molecular Research     Open Access   (Followers: 4)
Geomicrobiology Journal     Hybrid Journal   (Followers: 2)
Gut Microbes     Full-text available via subscription   (Followers: 8)
IAWA Journal     Hybrid Journal  
Indian Journal of Microbiology     Hybrid Journal   (Followers: 2)
Indian Journal of Pathology and Microbiology     Open Access   (Followers: 1)
Infection Ecology & Epidemiology     Open Access   (Followers: 3)
Inside the Cell     Open Access  
International Journal of Antimicrobial Agents     Hybrid Journal   (Followers: 7)
International Journal of Bacteriology     Open Access  
International Journal of Bioassays     Open Access   (Followers: 2)
International Journal of Biotechnology and Molecular Biology Research     Open Access   (Followers: 2)
International Journal of Food Microbiology     Hybrid Journal   (Followers: 12)
International Journal of Genetics and Molecular Biology     Open Access  
International Journal of Infection and Microbiology     Open Access   (Followers: 1)
International Journal of Medical Microbiology     Hybrid Journal   (Followers: 8)
International Journal of Molecular Medicine     Full-text available via subscription   (Followers: 5)
International Journal of Mycobacteriology     Open Access  
International Journal of Systematic and Evolutionary Microbiology     Full-text available via subscription   (Followers: 3)
International Journal of Virology and Molecular Biology     Open Access  
International Microbiology     Open Access   (Followers: 4)
Invertebrate Immunity     Open Access   (Followers: 1)
JMM Case Reports     Open Access  
Journal of Cell Science & Therapy     Open Access   (Followers: 2)
Journal of Microbial & Biochemical Technology     Open Access   (Followers: 2)
Journal of Applied Biology & Biotechnology     Open Access   (Followers: 2)
Journal of Applied Microbiology     Hybrid Journal   (Followers: 14)
Journal of Bacteriology     Hybrid Journal   (Followers: 29)
Journal of Basic Microbiology     Hybrid Journal   (Followers: 3)
Journal of Biomolecular Structure and Dynamics     Hybrid Journal   (Followers: 2)
Journal of Bionanoscience     Full-text available via subscription  
Journal of Bone Marrow Research     Open Access   (Followers: 1)
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: 30)
Journal of Clinical Pathology     Full-text available via subscription   (Followers: 10)
Journal of Extracellular Vesicles     Open Access   (Followers: 4)
Journal of Food Microbiology     Open Access   (Followers: 4)
Journal of General and Molecular Virology     Open Access  
Journal of Genes and Cells     Open Access  
Journal of Global Antimicrobial Resistance     Hybrid Journal   (Followers: 2)
Journal of Industrial Microbiology and Biotechnology     Hybrid Journal   (Followers: 15)
Journal of Medical Microbiology     Full-text available via subscription   (Followers: 4)
Journal of Microbiological Methods     Hybrid Journal   (Followers: 2)
Journal of Microbiology     Hybrid Journal   (Followers: 8)
Journal of Microbiology and Antimicrobials     Open Access   (Followers: 2)
Journal of Microbiology Research     Open Access   (Followers: 4)
Journal of Micropalaeontology     Hybrid Journal   (Followers: 7)
Journal of Molecular Biochemistry     Open Access   (Followers: 3)
Journal of Molecular Biology Research     Open Access   (Followers: 3)
Journal of Molecular Microbiology and Biotechnology     Full-text available via subscription   (Followers: 13)
Journal of Molecular Psychiatry     Open Access   (Followers: 9)
Journal of Morphology     Hybrid Journal   (Followers: 5)
Journal of Pharmacy & Bioresources     Full-text available via subscription   (Followers: 3)
Journal of Plant Molecular Biology and Biotechnology     Open Access   (Followers: 8)
Journal of Plant Pathology & Microbiology     Open Access   (Followers: 1)
Journal of Proteome Science and Computational Biology     Open Access  
Journal of Rapid Methods and Automation In Microbiology     Hybrid Journal   (Followers: 5)
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: 6)
Macrophage     Open Access  
MAP Kinase     Open Access  
Medical Mycology     Open Access   (Followers: 5)
Memórias do Instituto Oswaldo Cruz     Open Access  
Methods in Molecular Biology     Hybrid Journal   (Followers: 24)
Microbes and Health     Open Access   (Followers: 1)
Microbes and Infection     Full-text available via subscription   (Followers: 5)
Microbial Biotechnology     Open Access   (Followers: 8)
Microbial Cell Factories     Open Access   (Followers: 7)
Microbial Drug Resistance     Hybrid Journal   (Followers: 4)
Microbial Ecology     Hybrid Journal   (Followers: 8)
Microbial Ecology in Health and Disease     Open Access  
Microbial Informatics and Experimentation     Open Access   (Followers: 1)
Microbial Pathogenesis     Hybrid Journal   (Followers: 7)
Microbial Risk Analysis     Full-text available via subscription  
Microbiologia Medica     Open Access   (Followers: 1)
Microbiological Research     Hybrid Journal   (Followers: 6)
Microbiology     Hybrid Journal   (Followers: 13)
Microbiology (SGM)     Full-text available via subscription   (Followers: 17)
Microbiology and Immunology     Hybrid Journal   (Followers: 10)
Microbiology and Molecular Biology Reviews     Hybrid Journal   (Followers: 23)
Microbiology Australia     Hybrid Journal  
Microbiology Discovery     Open Access   (Followers: 1)
Microbiology Indonesia     Open Access  
Microbiology Research     Open Access   (Followers: 7)
MicrobiologyOpen     Open Access   (Followers: 2)
Microbiome     Hybrid Journal   (Followers: 7)
Microbiome Science and Medicine     Open Access   (Followers: 2)
Microorganisms     Open Access   (Followers: 2)
MicroRNA     Hybrid Journal   (Followers: 1)
Molecular and Cellular Therapies     Open Access  
Molecular Biology and Genetic Engineering     Open Access   (Followers: 1)
Molecular Biology Research Communications     Open Access   (Followers: 1)
Molecular Genetics and Metabolism Reports     Open Access   (Followers: 2)
Molecular Genetics, Microbiology and Virology     Hybrid Journal   (Followers: 6)
Molecular Imaging     Open Access  
Molecular Imaging and Biology     Hybrid Journal   (Followers: 2)
Molecular Medicine     Open Access   (Followers: 3)
Molecular Medicine Reports     Full-text available via subscription   (Followers: 6)
Molecular Microbiology     Hybrid Journal   (Followers: 30)
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  [3041 journals]
  • Effect of cinnamon essential oil on bacterial diversity and shelf-life in
           
    • Authors: Yuemei Zhang; Dongping Li; Jian Lv; Qingzheng Li; Chunli Kong; Yongkang Luo
      Pages: 1 - 8
      Abstract: Publication date: 16 May 2017
      Source:International Journal of Food Microbiology, Volume 249
      Author(s): Yuemei Zhang, Dongping Li, Jian Lv, Qingzheng Li, Chunli Kong, Yongkang Luo
      The present study investigated the effect of cinnamon essential oil on the quality of vacuum-packaged common carp (Cyprinus carpio) fillets stored at 4±1°C in terms of sensory scores, physicochemical characteristics (total volatile basic nitrogen (TVB-N), biogenic amines, and color), and presence of spoilage microbiota. A total of 290,753 bacterial sequences and 162 different genera belonging to 14 phyla were observed by a high-throughput sequencing technique targeting the V3–V4 region of 16S rDNA, which showed a more comprehensive estimate of microbial diversity in carp samples compared with microbial enumeration. Before storage, Macrococcus and Aeromonas were the prevalent populations in the control samples, but cinnamon essential oil decreased the relative abundance of Macrococcus in the treated samples. Variability in the predominant microbiota in different samples during chilled storage was observed. Aeromonas followed by Lactococcus were the major contaminants in the spoiled control samples. Microbial enumeration also observed relatively higher counts of Aeromonas than other spoilage microorganisms. Compared with the control samples, cinnamon essential oil inhibited the growth of Aeromonas and Lactococcus were the predominant components in the treated samples on day 10; plate counts also revealed a relatively high level of lactic acid bacteria during refrigerated storage. However, there were no significant differences (P >0.05) in the composition of dominant microbiota between these two treatments at the end of the shelf-life. Furthermore, cinnamon essential oil treatment was more effective in inhibiting the increase of TVB-N and the accumulation of biogenic amines (especially for putrescine and cadaverine levels). Based primarily on sensory analysis, the use of cinnamon essential oil extended the shelf-life of vacuum-packaged common carp fillets by about 2days.

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

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

      PubDate: 2017-03-09T14:44:54Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.015
      Issue No: Vol. 249 (2017)
       
  • Prevalence of foodborne pathogens in food from selected African countries
           – A meta-analysis
    • Authors: Narayan Paudyal; Victor Anihouvi; Joseph Hounhouigan; Maitshwarelo Ignatius Matsheka; Bonno Sekwati-Monang; Wisdom Amoa-Awua; Amy Atter; Nina Bernice Ackah; Samuel Mbugua; Agnes Asagbra; Warda Abdelgadir; Jesca Nakavuma; Mogens Jakobsen; Weihuan Fang
      Pages: 35 - 43
      Abstract: Publication date: 16 May 2017
      Source:International Journal of Food Microbiology, Volume 249
      Author(s): Narayan Paudyal, Victor Anihouvi, Joseph Hounhouigan, Maitshwarelo Ignatius Matsheka, Bonno Sekwati-Monang, Wisdom Amoa-Awua, Amy Atter, Nina Bernice Ackah, Samuel Mbugua, Agnes Asagbra, Warda Abdelgadir, Jesca Nakavuma, Mogens Jakobsen, Weihuan Fang
      Food safety information in the African region is insufficient and fragmented due to lack of surveillance, documentation and reporting, thereby resulting in inefficient utilization of resources, duplication of activities, and lack of synergy among the countries of the region. This paper reviews the prevalence of foodborne pathogens in seven African countries (Benin, Botswana, Ghana, Kenya, Nigeria, Sudan and Uganda) from papers in regional or international journals published between January 2000 and December 2015. One hundred and sixteen publications that dealt with food microbiology were reviewed for general analysis, while 66 papers on contamination of pathogenic bacteria were used for meta-analysis of prevalence. The food items were split into two categories: raw foods and ready-to-eat (RTE) foods (including street food and beverages) for meta-analysis. Majority of the reviewed studies (67.2%, 78/116) dealt with food of animal origin: 38.8% for meat and eggs, 17.2% for dairy products and 11.2% for aquatic products. Only 8.6% examined foods of plant origin (fruits and vegetables). The remaining 24.1% was the composite RTE food and beverages. Enterobacteriaceae, Escherichia coli, Salmonella, Staphylococcus aureus and Listeria monocytogenes were the most frequently reported organisms in those studies. Although the data were highly heterogeneous, a striking feature is high prevalence of the major pathogens in RTE foods, almost as high as in raw foods. E. coli averaged at 37.6% in raw foods and 31.6% in RTE foods. The corresponding prevalence for Salmonella was 19.9% vs 21.7%; S. aureus, 27.8% vs 25.1% and L. monocytogenes, 19.5% vs 6.7%. The average prevalence of foodborne pathogens in these countries was 34.2% (29.0–39.3%). Differences in food types as well as non-uniform protocols for sampling and identification might have contributed to high heterogeneity (I2 >97%) although some high prevalence data could be factual with extensive varieties of raw and RTE foods. Need for improved hygienic practices in handling of raw or RTE foods are suggested. Implementation of surveillance programs that use uniform laboratory protocols across the region could give homogeneous results.

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

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

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

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

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

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

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

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

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

      PubDate: 2017-02-25T07:31:30Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.011
      Issue No: Vol. 248 (2017)
       
  • Lactic acid fermentation drives the optimal volatile flavor-aroma profile
           of pomegranate juice
    • Authors: Raffaella Di Cagno; Pasquale Filannino; Marco Gobbetti
      Pages: 56 - 62
      Abstract: Publication date: 2 May 2017
      Source:International Journal of Food Microbiology, Volume 248
      Author(s): Raffaella Di Cagno, Pasquale Filannino, Marco Gobbetti
      Pomegranate juice (PJ) fermented with Lactobacillus plantarum C2, POM1, and LP09, unstarted-PJ, and raw-PJ were characterized for the profile of the volatile components (VOC) by PT–GC–MS. Lactic acid fermentation through selected strains enhanced the flavor profile of PJ. Concentrations of desired compounds (e.g., alcohols, ketones, and terpenes) were positively affected, whereas those of non-desired aldehydes decreased. Unstarted-PJ mainly differentiated from fermented PJs for the highest levels of aldehydes and sulfur compounds, and in lesser extent of furans, whereas alcohols, ketones, and alkenes followed by terpenes and benzene derivatives mainly differentiated fermented PJs. As expected, the lowest level of VOC was found in raw-PJ. VOC profile reflected on the sensory features of fermented PJs, unstarted-PJ, and raw-PJ, which were evaluated using a consensus modified flavor profile based on 13 attributes. Fermented PJs were mainly discriminated by the higher intensity of floral, fruity and anise notes than the controls.

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

      PubDate: 2017-03-04T14:39:21Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.012
      Issue No: Vol. 248 (2017)
       
  • Listeria monocytogenes ability to survive desiccation: Influence of
           serotype, origin, virulence, and genotype
    • Authors: Fiona Zoz; Cosette Grandvalet; Emilie Lang; Cyril Iaconelli; Patrick Gervais; Olivier Firmesse; Stéphane Guyot; Laurent Beney
      Pages: 82 - 89
      Abstract: Publication date: 2 May 2017
      Source:International Journal of Food Microbiology, Volume 248
      Author(s): Fiona Zoz, Cosette Grandvalet, Emilie Lang, Cyril Iaconelli, Patrick Gervais, Olivier Firmesse, Stéphane Guyot, Laurent Beney
      Listeria monocytogenes, a bacterium that is responsible for listeriosis, is a very diverse species. Desiccation resistance has been rarely studied in L. monocytogenes, although it is a stress that is largely encountered by this microorganism in food-processing environments and that could be managed to prevent its presence. The objective of this study was to evaluate the resistance of 30 L. monocytogenes strains to moderate desiccation (75% relative humidity) and evaluate the correlation of such resistance with the strains' virulence, serotype and genotype. The results showed a great heterogeneity of strains regarding their ability to survive (loss of cultivability between 0.4 and 2.0 log). Strains were classified into three groups according to desiccation resistance (sensitive, intermediate, or resistant), and the strain repartition was analyzed relative to serotype, virulence level and environmental origin of the strains. No correlation was found between isolate origin and desiccation resistance. All serotype 1/2b strains were classified into the group of resistant strains. Virulent and hypovirulent strains were distributed among the three groups of desiccation resistance. Finally, a genomic comparison was performed based on 31 genes that were previously identified as being involved in desiccation resistance. The presence of those genes was localized among the genomes of some strains and compared regarding strain-resistance levels. High nucleotide conservation was identified between resistant and desiccation-sensitive strains. In conclusion, the findings regarding the strains of serotype 1/2b indicate potential serotype-specific resistance to desiccation, and thus, to relative humidity fluctuations potentially encountered in food-related environments. The genomic comparison of 31 genes associated to desiccation tolerance did not reveal differences among four strains which have different level of resistance to desiccation.

      PubDate: 2017-03-16T18:29:21Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.010
      Issue No: Vol. 248 (2017)
       
  • 20th Club des Bactéries Lactiques: New challenges for research and
           industry
    • Authors: Djamel Drider
      First page: 1
      Abstract: Publication date: 17 April 2017
      Source:International Journal of Food Microbiology, Volume 247
      Author(s): Djamel Drider


      PubDate: 2017-03-21T16:58:51Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.008
      Issue No: Vol. 247 (2017)
       
  • MALDI-TOF mass spectrometry for the identification of lactic acid bacteria
           isolated from a French cheese: The Maroilles
    • Authors: Menouar Nacef; Mickaël Chevalier; Sylvie Chollet; Djamel Drider; Christophe Flahaut
      Pages: 2 - 8
      Abstract: Publication date: 17 April 2017
      Source:International Journal of Food Microbiology, Volume 247
      Author(s): Menouar Nacef, Mickaël Chevalier, Sylvie Chollet, Djamel Drider, Christophe Flahaut
      In this study we identified the culturable population of mesophilic lactic acid bacteria (LAB) from a French cheese Maroilles made either with raw or pasteurized milk using MALDI-TOF mass spectrometry (MS). Samples from rind and heart of Maroilles cheese were used, the LAB were selected on MRS agar at 30°C and 197 Gram-positive and catalase-negative strains were subjected to identification by MALDI-TOF MS profiling. All strains were unambiguously identified: 105 strains from Maroilles made with raw milk (38 on the rind and 67 in the heart) and 92 strains from Maroilles made with pasteurized milk (39 on the rind and 53 in the heart). MALDI-TOF MS identification allowed identification of three genera belonging to LAB including Lactobacillus, Enterococcus and Leuconostoc. Lactobacillus was the most represented genus with seven species: Lactobacillus plantarum (L. plantarum), L. paracasei, L. curvatus, L. rhamnosus, L. fructivorans, L. parabuchneri, L. brevis found in Maroilles made with both kind of milk. The correlation between the 16S rDNA-based identification performed on selected strains and those obtained by MALDI-TOF-MS demonstrates that this fast, economically affordable, robust and reliable method for bacteria characterisation stands as an attractive alternative to the commonly-used methods and its application in food industry is discussed.

      PubDate: 2017-03-21T16:58:51Z
      DOI: 10.1016/j.ijfoodmicro.2016.07.005
      Issue No: Vol. 247 (2017)
       
  • Use of the potential probiotic strain Lactobacillus salivarius SMXD51 to
           control Campylobacter jejuni in broilers
    • Authors: Manuel Jimmy Saint-Cyr; Nabila Haddad; Bernard Taminiau; Typhaine Poezevara; Ségolène Quesne; Michel Amelot; Georges Daube; Marianne Chemaly; Xavier Dousset; Muriel Guyard-Nicodème
      Pages: 9 - 17
      Abstract: Publication date: 17 April 2017
      Source:International Journal of Food Microbiology, Volume 247
      Author(s): Manuel Jimmy Saint-Cyr, Nabila Haddad, Bernard Taminiau, Typhaine Poezevara, Ségolène Quesne, Michel Amelot, Georges Daube, Marianne Chemaly, Xavier Dousset, Muriel Guyard-Nicodème
      Campylobacteriosis is the most frequently reported zoonotic disease in humans in the EU since 2005. As chicken meat is the main source of contamination, reducing the level of Campylobacter in broiler chicken will lower the risk to consumers. The aim of this project was to evaluate the ability of Lactobacillus salivarius SMXD51 to control Campylobacter jejuni in broilers and to investigate the mechanisms that could be involved. Thirty broilers artificially contaminated with C. jejuni were treated by oral gavage with MRS broth or a bacterial suspension (107 CFU) of Lb. salivarius SMXD51 (SMXD51) in MRS broth. At 14 and 35days of age, Campylobacter and Lb. salivarius loads were assessed in cecal contents. The impact of the treatment on the avian gut microbiota at day 35 was also evaluated. At day 14, the comparison between the control and treated groups showed a significant reduction (P <0.05) of 0.82 log. After 35days, a significant reduction (P <0.001) of 2.81 log in Campylobacter loads was observed and 73% of chickens treated with the culture exhibited Campylobacter loads below 7log10 CFU/g. Taxonomic analysis revealed that SMXD51 treatment induced significant changes (P <0.05) in a limited number of bacterial genera of the avian gut microbiota and partially limited the impact of Campylobacter on Anaerotruncus sp. decrease and Subdoligranulum sp. increase. Thus, SMXD51 exhibits an anti-Campylobacter activity in vivo and can partially prevent the impact of Campylobacter on the avian gut microbiota.

      PubDate: 2017-03-21T16:58:51Z
      DOI: 10.1016/j.ijfoodmicro.2016.07.003
      Issue No: Vol. 247 (2017)
       
  • Production of the small heat shock protein Lo18 from Oenococcus oeni in
           Lactococcus lactis improves its stress tolerance
    • Authors: Stéphanie Weidmann; Magali Maitre; Julie Laurent; Françoise Coucheney; Aurélie Rieu; Jean Guzzo
      Pages: 18 - 23
      Abstract: Publication date: 17 April 2017
      Source:International Journal of Food Microbiology, Volume 247
      Author(s): Stéphanie Weidmann, Magali Maitre, Julie Laurent, Françoise Coucheney, Aurélie Rieu, Jean Guzzo
      Lactococcus lactis is a lactic acid bacterium widely used in cheese and fermented milk production. During fermentation, L. lactis is subjected to acid stress that impairs its growth. The small heat shock protein (sHsp) Lo18 from the acidophilic species Oenococcus oeni was expressed in L. lactis. This sHsp is known to play an important role in protein protection and membrane stabilization in O. oeni. The role of this sHsp could be studied in L. lactis, since no gene encoding for sHsp has been detected in this species. L. lactis subsp. cremoris strain MG1363 was transformed with the pDLhsp18 plasmid, which is derived from pDL278 and contains the hsp18 gene (encoding Lo18) and its own promoter sequence. The production of Lo18 during stress conditions was checked by immunoblotting and the cellular distribution of Lo18 in L. lactis cells after heat shock was determined. Our results clearly indicated a role for Lo18 in cytoplasmic protein protection and membrane stabilization during stress. The production of sHsp in L. lactis improved tolerance to heat and acid conditions in this species. Finally, the improvement of the L. lactis survival in milk medium thanks to Lo18 was highlighted, suggesting an interesting role of this sHsp. These findings suggest that the expression of a sHsp by a L. lactis strain results in greater resistance to stress, and, can consequently enhance the performances of industrial strains.

      PubDate: 2017-03-21T16:58:51Z
      DOI: 10.1016/j.ijfoodmicro.2016.06.005
      Issue No: Vol. 247 (2017)
       
  • Exploring the metabolic heterogeneity of coagulase-negative staphylococci
           to improve the quality and safety of fermented meats: a review
    • Authors: María Sánchez Mainar; Despoina Angeliki Stavropoulou; Frédéric Leroy
      Pages: 24 - 37
      Abstract: Publication date: 17 April 2017
      Source:International Journal of Food Microbiology, Volume 247
      Author(s): María Sánchez Mainar, Despoina Angeliki Stavropoulou, Frédéric Leroy
      The production of fermented meats, such as fermented sausage, relies on the metabolic activities of lactic acid bacteria and catalase-positive cocci, in particular the group of coagulase-negative staphylococci (CNS). Conventional use of CNS as meat starter cultures usually leads to an appropriate cured colour development based on their nitrate reductase activity, whereas their catalase activity reduces oxidative damage. In addition, CNS metabolism contributes to flavour, although the precise effects are difficult to estimate. There are reasons to believe that these basic technological features of CNS can be further enlarged by exploring their full metabolic potential. Non-negligible differences in metabolism among and within different species of CNS indicate that a rational selection of strains may lead to the development of novel starter cultures with enhanced functionality. Firstly, the use of CNS strains with a superior ability to use alternative energy sources, such as nucleosides or arginine, may improve culture competitiveness and survival. Secondly, cured colour generation could be optimised to lower the amounts of curing salts needed, either by selecting for efficient nitrate-reducing CNS strains or by exploring the potential alternative based on nitric oxide synthase activity. Thirdly, CNS with specific aroma-producing abilities may help to accentuate specific flavours, whereby the selection of wild-type strains from artisan-type fermented sausages seems attractive in the framework of innovation-through-tradition. Finally, bacteriocin-producing CNS strains may offer solutions for bioprotection towards meat pathogens such as Clostridium botulinum and Staphylococcus aureus. Overall, making use of the metabolic inter- and intraspecies heterogeneity of CNS is promising for the elaboration of healthier, tastier, and safer fermented meats. Yet, the proposed strategies are sometimes still overly theoretical and speculative, requiring further proof-of-principle.

      PubDate: 2017-03-21T16:58:51Z
      DOI: 10.1016/j.ijfoodmicro.2016.05.021
      Issue No: Vol. 247 (2017)
       
  • A method to isolate bacterial communities and characterize ecosystems from
           food products: Validation and utilization in as a reproducible chicken
           meat model
    • Authors: Amélie Rouger; Benoit Remenant; Hervé Prévost; Monique Zagorec
      Pages: 38 - 47
      Abstract: Publication date: 17 April 2017
      Source:International Journal of Food Microbiology, Volume 247
      Author(s): Amélie Rouger, Benoit Remenant, Hervé Prévost, Monique Zagorec
      Influenced by production and storage processes and by seasonal changes the diversity of meat products microbiota can be very variable. Because microbiotas influence meat quality and safety, characterizing and understanding their dynamics during processing and storage is important for proposing innovative and efficient storage conditions. Challenge tests are usually performed using meat from the same batch, inoculated at high levels with one or few strains. Such experiments do not reflect the true microbial situation, and the global ecosystem is not taken into account. Our purpose was to constitute live stocks of chicken meat microbiotas to create standard and reproducible ecosystems. We searched for the best method to collect contaminating bacterial communities from chicken cuts to store as frozen aliquots. We tested several methods to extract DNA of these stored communities for subsequent PCR amplification. We determined the best moment to collect bacteria in sufficient amounts during the product shelf life. Results showed that the rinsing method associated to the use of Mobio DNA extraction kit was the most reliable method to collect bacteria and obtain DNA for subsequent PCR amplification. Then, 23 different chicken meat microbiotas were collected using this procedure. Microbiota aliquots were stored at −80°C without important loss of viability. Their characterization by cultural methods confirmed the large variability (richness and abundance) of bacterial communities present on chicken cuts. Four of these bacterial communities were used to estimate their ability to regrow on meat matrices. Challenge tests performed on sterile matrices showed that these microbiotas were successfully inoculated and could overgrow the natural microbiota of chicken meat. They can therefore be used for performing reproducible challenge tests mimicking a true meat ecosystem and enabling the possibility to test the influence of various processing or storage conditions on complex meat matrices.

      PubDate: 2017-03-21T16:58:51Z
      DOI: 10.1016/j.ijfoodmicro.2016.04.028
      Issue No: Vol. 247 (2017)
       
  • Lactobacillus plantarum with broad antifungal activity: A promising
           approach to increase safety and shelf-life of cereal-based products
    • Authors: Pasquale Russo; Mattia Pia Arena; Daniela Fiocco; Vittorio Capozzi; Djamel Drider; Giuseppe Spano
      Pages: 48 - 54
      Abstract: Publication date: 17 April 2017
      Source:International Journal of Food Microbiology, Volume 247
      Author(s): Pasquale Russo, Mattia Pia Arena, Daniela Fiocco, Vittorio Capozzi, Djamel Drider, Giuseppe Spano
      Cereal-based fermented products are worldwide diffused staple food resources and cereal-based beverages represent a promising innovative field in the food market. Contamination and development of spoilage filamentous fungi can result in loss of cereal-based food products and it is a critical safety concern due to their potential ability to produce mycotoxins. Lactic Acid Bacteria (LAB) have been proposed as green strategy for the control of the moulds in the food industry due to their ability to produce antifungal metabolites. In this work, eighty-eight Lactobacillus plantarum strains were screened for their antifungal activity against Aspergillus niger, Aspergillus flavus, Fusarium culmorum, Penicillium roqueforti, Penicillium expansum, Penicillium chrysogenum, and Cladosporium spp. The overlayed method was used for a preliminary discrimination of the strains as no, mild and strong inhibitors. L. plantarum isolates that displayed broad antifungal spectrum activity were further screened based on the antifungal properties of their cell-free supernatant (CFS). CFSs from L. plantarum UFG 108 and L. plantarum UFG 121, in reason of their antifungal potential, were characterized and analyzed by HPLC. Results indicated that lactic acid was produced at high concentration during the growth phase, suggesting that this metabolic aptitude, associated with the low pH, contributed to explain the highlighted antifungal phenotype. Production of phenyllactic acid was also observed. Finally, a new oat-based beverage was obtained by fermentation with the strongest antifungal strain L. plantarum UFG 121. This product was submitted or not to a thermal stabilization and artificially contaminated with F. culmorum. Samples containing L. plantarum UFG 121 showed the best biopreservative effects, since that no differences were observed in terms of some qualitative features between not or contaminated samples with F. culmorum. Here we demonstrate, for the first time, the suitability of LAB strains for the fermentation and antifungal biopreservation of oat-based products.

      PubDate: 2017-03-21T16:58:51Z
      DOI: 10.1016/j.ijfoodmicro.2016.04.027
      Issue No: Vol. 247 (2017)
       
  • Streptococcus thermophilus urease activity boosts Lactobacillus
           delbrueckii subsp. bulgaricus homolactic fermentation
    • Authors: Stefania Arioli; Giulia Della Scala; Maria Chiara Remagni; Milda Stuknyte; Stefano Colombo; Simone Guglielmetti; Ivano De Noni; Enzio Ragg; Diego Mora
      Pages: 55 - 64
      Abstract: Publication date: 17 April 2017
      Source:International Journal of Food Microbiology, Volume 247
      Author(s): Stefania Arioli, Giulia Della Scala, Maria Chiara Remagni, Milda Stuknyte, Stefano Colombo, Simone Guglielmetti, Ivano De Noni, Enzio Ragg, Diego Mora
      The proto-cooperation between Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus in the yogurt consortium enhances the growth rate and size of each population. In contrast, the independent growth of the two species in milk leads to a slower growth rate and a smaller population size. In this study, we report the first evidence that the urease activity of S. thermophilus increases the intracellular pH of L. delbrueckii in the absence of carbon source. However, in milk, in the presence of lactose the alkalizing effect of urea-derived ammonia was not detectable. Nevertheless, based on glucose consumption and lactic acid production at different pHin, L. delbrueckii showed an optimum of glycolysis and homolactic fermentation at alkaline pH values. In milk, we observed that ammonia provided by urea hydrolysis boosted lactic acid production in S. thermophilus and in L. delbrueckii when the species were grown alone or in combination. Therefore, we propose that urease activity acts as an altruistic cooperative trait, which is costly for urease-positive individuals but provides a local benefit because other individuals can take advantage of urease-dependent ammonia release.

      PubDate: 2017-03-21T16:58:51Z
      DOI: 10.1016/j.ijfoodmicro.2016.01.006
      Issue No: Vol. 247 (2017)
       
  • Use of a metagenetic approach to monitor the bacterial microbiota of
           “Tomme d'Orchies” cheese during the ripening process
    • Authors: Alexandre Ceugniez; Bernard Taminiau; Françoise Coucheney; Philippe Jacques; Véronique Delcenserie; Georges Daube; Djamel Drider
      Pages: 65 - 69
      Abstract: Publication date: 17 April 2017
      Source:International Journal of Food Microbiology, Volume 247
      Author(s): Alexandre Ceugniez, Bernard Taminiau, Françoise Coucheney, Philippe Jacques, Véronique Delcenserie, Georges Daube, Djamel Drider
      The study of microbial ecosystems in artisanal foodstuffs is important to complete in order to unveil its diversity. The number of studies performed on dairy products has increased during the last decade, particularly those performed on milk and cheese derivative products. In this work, we investigated the bacterial content of “Tomme d'Orchies” cheese, an artisanal pressed and uncooked French cheese. To this end, a metagenetic analysis, using Illumina technology, was utilized on samples taken from the surface and core of the cheese at 0, 1, 3, 14 and 21days of ripening process. In addition to the classical microbiota found in cheese, various strains likely from environmental origin were identified. A large difference between the surface and the core content was observed within samples withdrawn during the ripening process. The main species encountered in the core of the cheese were Lactococcus spp. and Streptococcus spp., with an inversion of this ratio during the ripening process. Less than 2.5% of the whole population was composed of strains issued from environmental origin, as Lactobacillales, Corynebacterium and Brevibacterium. In the core, about 85% of the microbiota was attributed to the starters used for the cheese making. In turn, the microbiota of the surface contained less than 30% of these starters and interestingly displayed more diversity. The predominant genus was Corynebacterium sp., likely originating from the environment. The less abundant microbiota of the surface was composed of Bifidobacteria, Brevibacterium and Micrococcales. To summarize, the “Tomme d'Orchies” cheese displayed a high diversity of bacterial species, especially on the surface, and this diversity is assumed to arise from the production environment and subsequent ripening process.

      PubDate: 2017-03-21T16:58:51Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.034
      Issue No: Vol. 247 (2017)
       
  • The use of 16S rRNA gene metagenetic monitoring of refrigerated food
           products for understanding the kinetics of microbial subpopulations at
           different storage temperatures: the example of white pudding
    • Authors: Emilie Cauchie; Mathieu Gand; Gilles Kergourlay; Bernard Taminiau; Laurent Delhalle; Nicolas Korsak; Georges Daube
      Pages: 70 - 78
      Abstract: Publication date: 17 April 2017
      Source:International Journal of Food Microbiology, Volume 247
      Author(s): Emilie Cauchie, Mathieu Gand, Gilles Kergourlay, Bernard Taminiau, Laurent Delhalle, Nicolas Korsak, Georges Daube
      In order to control food losses and wastage, monitoring the microbial diversity of food products, during processing and storage is important, as studies have highlighted the metabolic activities of some microorganisms which can lead to spoilage. Knowledge of this diversity can be greatly improved by using a metagenetic approach based on high throughput 16S rRNA gene sequencing, which enables a much higher resolution than culture-based methods. Moreover, the Jameson effect, a phenomenon described by Jameson in 1962, is often used to classify bacterial strains within an ecosystem. According to this, we have studied the bacterial microbiota of Belgian white pudding during storage at different temperatures using culture-dependent and independent methods. The product was inoculated with a mix of dominant strains previously isolated from this foodstuff at the end of its shelf life (Carnobacterium maltaromaticum, Lactobacillus fuchuensis, Lactobacillus graminis, Lactobacillus oligofermentans, Lactococcus lactis, Leuconostoc mesenteroides, Raoultella terrigena and Serratia sp.). Daily during 16days, the absolute abundance of inoculated strain was monitored by combining total count on plate agar and metagenetic analysis. The results were confirmed by qPCR analysis. The growth of each species was modelled for each temperature conditions, representative of good or bad storage practices. These data allowed the bacterial strains subdivision into three classes based on criteria of growth parameters for the studied temperature: the “dominant”, the “subdominant” and the “inhibited” bacterial species, according to their maximal concentration (Nmax, log CFU/g), growth rate (μmax, 1/h) and time to reach the stationary phase (TRSP, days). Thereby, depending on the storage conditions, these data have permitted to follow intrinsically the evolution of each strain on the bacterial ecosystem of Belgian white pudding. Interestingly, it has shown that the reliability of the Jameson effect can be discussed. For example, at 4°C when Lactococcus lactis and Serratia sp. stopped growth at day 12, at the same time Carnobacterium maltaromaticum reached its maximal concentration and entered its stationary phase. In opposition to this, it can be noticed that in the same condition, the “sub-dominant” organisms continued their growth independently of the “dominant” species behaviour. In this case, the Jameson effect was not illustrated. This pattern is described for all storage conditions with the same strain classifications. These results highlighted the importance of combining metagenetic analysis and classical methods, with modelling, to offer a new tool for studying the evolution of microorganisms present in perishable food within different environmental conditions.

      PubDate: 2017-03-21T16:58:51Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.012
      Issue No: Vol. 247 (2017)
       
  • Assessment of bacterial superficial contamination in classical or ritually
           slaughtered cattle using metagenetics and microbiological analysis
    • Authors: N. Korsak; B. Taminiau; C. Hupperts; L. Delhalle; C. Nezer; V. Delcenserie; G. Daube
      Pages: 79 - 86
      Abstract: Publication date: 17 April 2017
      Source:International Journal of Food Microbiology, Volume 247
      Author(s): N. Korsak, B. Taminiau, C. Hupperts, L. Delhalle, C. Nezer, V. Delcenserie, G. Daube
      The aim of this study was to investigate the influence of the slaughter technique (Halal vs Classical slaughter) on the superficial contamination of cattle carcasses, by using traditional microbiological procedures and 16S rDNA metagenetics. The purpose was also to investigate the neck area to identify bacteria originating from the digestive or the respiratory tract. Twenty bovine carcasses (10 from each group) were swabbed at the slaughterhouse, where both slaughtering methods are practiced. Two swabbing areas were chosen: one “legal” zone of 1600cm2 (composed of zones from rump, flank, brisket and forelimb) and locally on the neck area (200cm2). Samples were submitted to classical microbiology for aerobic Total Viable Counts (TVC) at 30°C and Enterobacteriaceae counts, while metagenetic analysis was performed on the same samples. The classical microbiological results revealed no significant differences between both slaughtering practices; with values between 3.95 and 4.87log CFU/100cm2 and 0.49 and 1.94log CFU/100cm2, for TVC and Enterobacteriaceae respectively. Analysis of pyrosequencing data showed that differences in the bacterial population abundance between slaughtering methods were mainly observed in the “legal” swabbing zone compared to the neck area. Bacterial genera belonging to the Actinobacteria phylum were more abundant in the “legal” swabbing zone in “Halal” samples, while Brevibacterium and Corynebacterium were encountered more in “Halal” samples, in all swabbing areas. This was also the case for Firmicutes bacterial populations (families of Aerococcaceae, Planococcaceae). Except for Planococcoceae, the analysis of Operational Taxonomic Unit (OTU) abundances of bacteria from the digestive or respiratory tract revealed no differences between groups. In conclusion, the slaughtering method does not influence the superficial microbiological pattern in terms of specific microbiological markers of the digestive or respiratory tract. However, precise analysis of taxonomy at the genus level taxonomy highlights differences between swabbing areas. Although not clearly proven in this study, differences in hygiene practices used during both slaughtering protocols could explain the differences in contamination between carcasses from both slaughtering groups.

      PubDate: 2017-03-21T16:58:51Z
      DOI: 10.1016/j.ijfoodmicro.2016.10.013
      Issue No: Vol. 247 (2017)
       
  • Effect of chitosan and SO2 on viability of Acetobacter strains in wine
    • Authors: Maria José Valera; Florencia Sainz; Albert Mas; María Jesús Torija
      Pages: 1 - 4
      Abstract: Publication date: 4 April 2017
      Source:International Journal of Food Microbiology, Volume 246
      Author(s): Maria José Valera, Florencia Sainz, Albert Mas, María Jesús Torija
      Wine spoilage is an important concern for winemakers to preserve the quality of their final product and avoid contamination throughout the production process. The use of sulphur dioxide (SO2) is highly recommended to prevent wine spoilage due to its antimicrobial activity. However, SO2 has a limited effect on the viability of acetic acid bacteria (AAB). Currently, the use of SO2 alternatives is favoured in order to reduce the use of chemicals and improve stabilization in winemaking. Chitosan is a biopolymer that is approved by the European authorities and the International Organization of Vine and Wine to be used as a fining agent and antimicrobial in wines. However, its effectiveness in AAB prevention has not been studied. Two strains of Acetobacter, adapted to high ethanol environments, were analysed in this study. Both chitosan and SO2 effects were compared in artificially contaminated wines. Both molecules reduced the metabolic activity of both AAB strains. Although AAB populations were detected by culture independent techniques, their numbers were reduced with time, and their viability decreased following the application of both products, especially with chitosan.

      PubDate: 2017-02-12T07:27:04Z
      DOI: 10.1016/j.ijfoodmicro.2017.01.022
      Issue No: Vol. 246 (2017)
       
  • Experimental effect of ozone upon the microbial flora of commercially
           produced dairy fermented products
    • Authors: A. Alexopoulos; S. Plessas; Y. Kourkoutas; C. Stefanis; S. Vavias; C. Voidarou; I. Mantzourani; E. Bezirtzoglou
      Pages: 5 - 11
      Abstract: Publication date: 4 April 2017
      Source:International Journal of Food Microbiology, Volume 246
      Author(s): A. Alexopoulos, S. Plessas, Y. Kourkoutas, C. Stefanis, S. Vavias, C. Voidarou, I. Mantzourani, E. Bezirtzoglou
      Ozone was used to control spoilage microorganisms during the manufacturing of dairy products. Ozone stream was applied onto the surface of freshly filled yoghurt cups just before storage for curd development in order to prevent cross contamination from spoilage airborne microorganisms. Accordingly, brine solution was bubbled with ozone for various periods of time and used for ripening of white (feta type) cheese. Both products were subjected to a continuous monitoring of microbial load and also tested for their sensorial properties. In ozonated yoghurt samples there was a reduction in mould counts of approximately 0.6Logcfu/g (25.1%) by the end of the monitoring period in relation to the control samples. In white cheese ripened with ozonated brine (1.3mg/L O3, NaCl 5%) it seems that ozone treatment during the two months of observation reduced some of the mould load but without offering any advantages over the use of traditional brine (NaCl 7%). However, some sensorial alterations were observed, probably due to the organic load in the brine which deactivates ozone in early stages of application. It is concluded that, if the factors of time and concentration of ozone are configured properly, ozonation could be a promising approach safeguarding the production of some dairy products.

      PubDate: 2017-02-12T07:27:04Z
      DOI: 10.1016/j.ijfoodmicro.2017.01.018
      Issue No: Vol. 246 (2017)
       
  • Phage-host interactions analysis of newly characterized Oenococcus oeni
           bacteriophages: Implications for malolactic fermentation in wine
    • Authors: Antonella Costantini; Francesca Doria; Juan-Carlos Saiz; Emilia Garcia-Moruno
      Pages: 12 - 19
      Abstract: Publication date: 4 April 2017
      Source:International Journal of Food Microbiology, Volume 246
      Author(s): Antonella Costantini, Francesca Doria, Juan-Carlos Saiz, Emilia Garcia-Moruno
      Nowadays, only few phages infecting Oenococcus oeni, the principal lactic acid bacteria (LAB) species responsible for malolactic fermentation (MLF) in wine, have been characterized. In the present study, to better understanding the factors affecting the lytic activity of Oenococcus phages, fifteen O. oeni bacteriophages have been studied in detail, both with molecular and microbiological methods. No correlations were found between genome sizes, type of integrase genes, or morphology and the lytic activity of the 15 tested phages. Interestingly, though phage attack in a wine at the end of alcoholic fermentation seems not to be a problem, it can indeed represent a risk factor for MLF when the alcohol content is low, feature that may be a key point for choosing the appropriate time for malolactic starter inoculation. Additionally, it was observed that some phages genomes bear 2 or 3 types of integrase genes, which point to horizontal gene transfer between O. oeni bacteriophages.

      PubDate: 2017-02-12T07:27:04Z
      DOI: 10.1016/j.ijfoodmicro.2017.01.020
      Issue No: Vol. 246 (2017)
       
  • Staphylococcal ecosystem of kitoza, a traditional malagasy meat product
    • Authors: Angela Ratsimba; Sabine Leroy; Jean Paul Chacornac; Danielle Rakoto; Elodie Arnaud; Victor Jeannoda; Régine Talon
      Pages: 20 - 24
      Abstract: Publication date: 4 April 2017
      Source:International Journal of Food Microbiology, Volume 246
      Author(s): Angela Ratsimba, Sabine Leroy, Jean Paul Chacornac, Danielle Rakoto, Elodie Arnaud, Victor Jeannoda, Régine Talon
      Kitoza is a traditional meat product from Madagascar manufactured with strips of pork or beef. The process includes a first step of salting and mixing with spices followed by sun-drying or smoking step. As salting and drying select coagulase-negative staphylococci (CNS), our aim was to identify the CNS species in kitoza with the objective in the future of developing indigenous starters. Microbial analyses revealed that the only pathogenic bacterium enumerated was Staphylococcus aureus, which was found in 54% of the samples. The level of Enterobacteriaceae revealed a rather good hygienic quality of these products. CNS were confirmed in all the samples at high levels ranging from 5 to 7logcfu/g. Identification of CNS species in a large collection of 829 isolates revealed 9 identified species, 7 for beef and 8 for pork kitoza. There were significant difference in the distribution of CNS species according to the type of meat and the process. Staphylococcus saprophyticus was the dominant species for sun-dried or smoked beef and sun-dried pork kitoza (73–75%), while for smoked pork kitoza Staphylococcus equorum (26%), S. saprophyticus (23%), Staphylococcus succinus (23%) and Staphylococcus epidermidis (17%) co-dominated. Some CNS could be used as indigenous starters in particular to compete against S. aureus.

      PubDate: 2017-02-12T07:27:04Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.001
      Issue No: Vol. 246 (2017)
       
  • Survey of Penicillia associated with Italian grana cheese
    • Authors: S. Decontardi; A. Mauro; N. Lima; P. Battilani
      Pages: 25 - 31
      Abstract: Publication date: 4 April 2017
      Source:International Journal of Food Microbiology, Volume 246
      Author(s): S. Decontardi, A. Mauro, N. Lima, P. Battilani
      The present work aimed to contribute information on the mycobiota associated with ripening grana cheese, with focus on the genus Penicillium as potential mycotoxin producers. Eighteen wheels of grana cheese, aged in different storehouses situated in Northern Italy, were sampled to isolate associated fungi. Penicillium spp. were commonly dominant; morphological observation and gene sequencing were applied to identify Penicillium at species level. P. crustosum and P. solitum were the dominant species. Citrinin and ochratoxin A mycotoxins were analysed and the latter was found in all grana cheese samples. These results confirmed that a polyphasic approach is mandatory for Penicillium identification at species level.

      PubDate: 2017-02-12T07:27:04Z
      DOI: 10.1016/j.ijfoodmicro.2017.01.019
      Issue No: Vol. 246 (2017)
       
  • Genetic and biochemical characterization of an oligo-α-1,6-glucosidase
           from Lactobacillus plantarum
    • Authors: Susana Delgado; Ana Belén Flórez; Lucía Guadamuro; Baltasar Mayo
      Pages: 32 - 39
      Abstract: Publication date: 4 April 2017
      Source:International Journal of Food Microbiology, Volume 246
      Author(s): Susana Delgado, Ana Belén Flórez, Lucía Guadamuro, Baltasar Mayo
      Although encoded in the genome of many Lactobacillus spp. strains, α-glucosidases have received little attention compared to other glycosyl hydrolases. In this study, a putative oligosaccharide(oligo)-α-1,6-glucosidase-encoding gene (malL) was identified in the genome of Lactobacillus plantarum LL441. malL coded for 572 amino acid residues with a calculated total molecular mass of 66.31kDa. No predicted signal peptide was observed, suggesting this enzyme to be localized within the cytoplasm of the cell. Homology studies of the deduced amino acid sequence in the area of its active sites classified the enzyme as a member of the α-amylase (AmyAC) superfamily of glycosyl hydrolases (GH), family 13 (GH13), subfamily 31 (GH13_31). malL was cloned in Escherichia coli and the coded enzyme overexpressed as a histidine-tagged protein (MalLHis). It was then purified and characterized. MalLHis protein showed strong hydrolytic activity towards 4-nitrophenyl-α-d-glucopyranoside (pNP-α-Glu) but not to other pNP-α-d- or pNP-β-d-derivatives. When using pNP-α-Glu as a substrate, MalLHis showed similar specific activities between pH5.0 and 6.0, and between 20 and 42°C (optimum 30°C). Among the natural carbohydrates assayed, MalLHis showed specificity towards isomaltose (V max and K m values of 40.64μmolmin−1 mg−1 and 6.22mM) and much less to isomaltulose (V max and K m values of 168.86μmolmin−1 mg−1 and 244.52mM). However, under the conditions of the assay, the enzyme showed no transglycosylation activity. Characterization of the entire complement of glycosidases in L. plantarum might reveal how strains of this species could be used in new biotechnological applications or in the development of functional foods.

      PubDate: 2017-02-12T07:27:04Z
      DOI: 10.1016/j.ijfoodmicro.2017.01.021
      Issue No: Vol. 246 (2017)
       
  • Hypoxia and iron requirements are the main drivers in transcriptional
           adaptation of Kluyveromyces lactis during wine aerobic fermentation
    • Authors: Jordi Tronchoni; Alda J. Rodrigues; Jose Antonio Curiel; Pilar Morales; Ramon Gonzalez
      Pages: 40 - 49
      Abstract: Publication date: 4 April 2017
      Source:International Journal of Food Microbiology, Volume 246
      Author(s): Jordi Tronchoni, Alda J. Rodrigues, Jose Antonio Curiel, Pilar Morales, Ramon Gonzalez
      The respiratory metabolism of yeast species alternative to Saccharomyces cerevisiae has been explored in recent years as a tool to reduce ethanol content in grape wine. The efficacy of this strategy has been previously proven for mixed cultures of non-Saccharomyces and S. cerevisiae strains. In this work, we perform a transcriptomic analysis of the Crabtree-negative yeast Kluyveromyces lactis under tightly controlled growth conditions in order to better understand physiology of non-Saccharomyces yeasts during the fermentation of grape must under aerated conditions. Transcriptional changes in K. lactis are mainly driven by oxygen limitation, iron requirement, and oxidative stress. Oxidative stress appears as a consequence of the hypoxic conditions achieved by K. lactis once oxygen supply is no longer sufficient to sustain fully respiratory metabolism. This species copes with low oxygen and iron availability by repressing iron consuming pathways and activating iron transport mechanisms. Most of the physiological and transcriptomic features of K. lactis in aerobic wine fermentation are not shared with the Crabtree-positive yeast S. cerevisiae.

      PubDate: 2017-02-12T07:27:04Z
      DOI: 10.1016/j.ijfoodmicro.2017.01.014
      Issue No: Vol. 246 (2017)
       
  • Assessing the capacity of growth, survival, and acid adaptive response of
           Listeria monocytogenes during storage of various cheeses and subsequent
           simulated gastric digestion
    • Authors: Anastasia E. Kapetanakou; Maria A. Gkerekou; Eirini S. Vitzilaiou; Panagiotis N. Skandamis
      Pages: 50 - 63
      Abstract: Publication date: 4 April 2017
      Source:International Journal of Food Microbiology, Volume 246
      Author(s): Anastasia E. Kapetanakou, Maria A. Gkerekou, Eirini S. Vitzilaiou, Panagiotis N. Skandamis
      Different physicochemical and microbiological characteristics of cheeses may affect Listeria monocytogenes potential to grow, survive, or exhibit an acid adaptive response during storage and digestion. The objectives of the present study were to assess: i) the survival or growth potential of L. monocytogenes on various cheeses during storage, ii) the effect of initial indigenous microbiota on pathogen growth in comparison to expected growth curves retrieved by existing predictive models, and iii) the impact of habituation on/in cheeses surfaces on the subsequent acid resistance during simulated gastric digestion. Portions of cream (Cottage and Mascarpone), soft (Anthotyros, Camembert, Mastelo®, Manouri, Mozzarella, Ricotta), and semi-hard (Edam, Halloumi, Gouda) cheeses were inoculated with ca. 100CFU/g or cm2 of L. monocytogenes and stored under vacuum or aerobic conditions at 7°C (n =4). The impact of varying (initial) levels of starter culture or indigenous spoilage microbiota on pathogen growth was evaluated by purchasing cheese packages on different dates in relation to production and expiration date (subsequently reflecting to different batches) mimicking a potential situation of cheese contamination with L. monocytogenes during retail display. Values of pH and aw were also monitored and used to simulate growth of L. monocytogenes by existing models and compare it with the observed data of the study. Survival in simulated gastric fluid (SGF) (pH1.5; HCl; max. 120min) was assessed at three time points during storage. Mascarpone, Ricotta, Mozzarella, Camembert, and Halloumi supported L. monocytogenes growth by 0.5–0.8logCFU/g or cm2 per day, since low initial levels of total viable counts (TVC) (1.8–3.8logCFU/g or cm2) and high pH/aw values (ca. 6.23–6.64/0.965–0.993) were recorded. On Cottage, Anthotyros, Manouri, Mastelo®, Edam, and Gouda, the pathogen survived at populations similar or lower than the inoculation level due to the high reported competition and/or low pH/aw during storage. L. monocytogenes growth was significantly suppressed (p <0.05) on samples purchased close to expiration date (bearing high TVC), compared to those close to production date, regardless of cheese. Cheeses which supported growth of L. monocytogenes enabled higher survival in gastric acidity along their shelf-life compared to cheeses which did not support growth. However, even in the latter cheeses (i.e., Cottage, Mastelo®, Gouda), total elimination of a persisting low initial contamination was not always achieved. Such findings may provide useful evidence for assessing the risk posed by various cheeses types in relation to their compliance with food safety regulations.

      PubDate: 2017-02-12T07:27:04Z
      DOI: 10.1016/j.ijfoodmicro.2017.01.015
      Issue No: Vol. 246 (2017)
       
  • The efficacy of different cleaning and disinfection procedures to reduce
           Salmonella and Enterobacteriaceae in the lairage environment of a pig
           abattoir
    • Authors: Kavita Walia; Hector Argüello; Helen Lynch; Jim Grant; Finola C. Leonard; Peadar G. Lawlor; Gillian E. Gardiner; Geraldine Duffy
      Pages: 64 - 71
      Abstract: Publication date: 4 April 2017
      Source:International Journal of Food Microbiology, Volume 246
      Author(s): Kavita Walia, Hector Argüello, Helen Lynch, Jim Grant, Finola C. Leonard, Peadar G. Lawlor, Gillian E. Gardiner, Geraldine Duffy
      This study investigated several cleaning and disinfection protocols for their ability to eliminate Salmonella and to reduce levels of Enterobacteriaceae, within the lairage pens of a commercial pig abattoir. Eight protocols were evaluated in each of 12 lairage pens at the end of the slaughtering day on 3 occasions (36 pens/protocol): (P1) high-pressure cold water wash (herein referred to as high-pressure wash); (P2) high-pressure wash followed by a quaternary ammonium compound (QAC)-based disinfectant without rinsing; (P3) high-pressure wash followed by a chlorocresol-based disinfectant without rinsing; (P4) high-pressure wash followed by a sodium hydroxide/sodium hypochlorite detergent with rinsing; (P5) P4 followed by P2; (P6) P4 followed by P3; (P7) P5 with drying for 24–48h; and (P8) P6 with drying for 24–48h. Two floor swabs and one wall swab were taken from each lairage pen before and after each protocol was applied, and examined for the presence of Salmonella and enumeration of Enterobacteriaceae. High-pressure washing alone (P1) did not reduce the prevalence of Salmonella in the lairage pens. When high-pressure washing, the probability of detecting Salmonella following application of the chlorocresol-based disinfectant (P3) was lower than with the QAC-based disinfectant, P2 (14.2% versus 34.0%, respectively; p<0.05). The probability of detecting Salmonella after the combined use of detergent and the chlorocresol-based disinfectant (P6) was also lower than application of detergent followed by the QAC-based disinfectant, P5 (2.2% versus 17.1%, respectively; p<0.05). Drying of pens (P7 and P8) greatly reduced the probability of detecting Salmonella. Only 3.8% of swabs were Salmonella-positive 48h after cleaning with detergent and the QAC-based disinfectant (P7); while an eradication of Salmonella was achieved 24h after cleaning with detergent and the chlorocresol-based disinfectant, P8. A reduction in Enterobacteriaceae counts to below the limit of detection (LOD; 10CFU/cm2) was achieved following cleaning with detergent and disinfection with the chlorocresol-based disinfectant, regardless of drying (p<0.05), whereas, applying detergent and the QAC-based disinfectant (P7) did not reduce Enterobacteriaceae counts to below the LOD. Therefore ensuring that lairage pens are allowed to dry after intensive cleaning with detergent and a chlorocresol-based disinfectant is recommended as the most effective hygiene routine to eliminate Salmonella and reduce Enterobacteriaceae counts.

      PubDate: 2017-02-12T07:27:04Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.002
      Issue No: Vol. 246 (2017)
       
  • Efficacy of fungal and bacterial antagonists for controlling growth, FUM1
           gene expression and fumonisin B1 production by Fusarium verticillioides on
           maize cobs of different ripening stages
    • Authors: Nik Iskandar Putra Samsudin; Alicia Rodriguez; Angel Medina; Naresh Magan
      Pages: 72 - 79
      Abstract: Publication date: 4 April 2017
      Source:International Journal of Food Microbiology, Volume 246
      Author(s): Nik Iskandar Putra Samsudin, Alicia Rodriguez, Angel Medina, Naresh Magan
      This study was carried out to examine the efficacy of two biocontrol agents (Clonostachys rosea 016, BCA1; Gram-negative bacterium, BCA5) for control of FUM1 gene expression and fumonisin B1 (FB1) production by F. verticillioides FV1 on maize cobs of different ripening stages: R3, Milk (0.985 a w); R4, Dough (0.976 a w); R5, Dent (0.958 a w). Initially, temporal studies on FUM1 gene expression and FB1 production were performed on maize kernels for up to 14days. This revealed that day 10 was optimum for both parameters, and was used in the biocontrol studies. Maize cobs were inoculated with 50:50 mixtures of the pathogen:antagonist inoculum and incubated in environmental chambers to maintain the natural a w conditions for ten days at 25 and 30°C. The growth rates of F. verticillioides FV1, the relative expression of the FUM1 gene and FB1 production were quantified. It was found that, a w ×temp had significant impacts on growth, FUM1 gene expression and FB1 production by F. verticillioides FV1 on maize cobs of different maturities. The fungal antagonist (BCA1) significantly reduced FB1 contamination on maize cobs by >70% at 25°C, and almost 60% at 30°C regardless of maize ripening stage. For the bacterial antagonist (BCA5) however, FB1 levels on maize cobs were significantly decreased only in some treatments. These results suggest that efficacy of antagonists to control mycotoxin production in ripening maize cobs needs to take account of the ecophysiology of the pathogen and the antagonists, as well as the physiological status of the maize during silking to ensure effective control.

      PubDate: 2017-02-17T07:32:27Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.004
      Issue No: Vol. 246 (2017)
       
  • Continuous ohmic heating of commercially processed apple juice using five
           sequential electric fields results in rapid inactivation of
           Alicyclobacillus acidoterrestris spores
    • Authors: N.H. Kim; J.H. Ryang; B.S. Lee; C.T. Kim; M.S. Rhee
      Pages: 80 - 84
      Abstract: Publication date: 4 April 2017
      Source:International Journal of Food Microbiology, Volume 246
      Author(s): N.H. Kim, J.H. Ryang, B.S. Lee, C.T. Kim, M.S. Rhee
      Spores of Alicyclobacillus acidoterrestris, a spoilage bacterium, cause problems for the apple juice industry because they are resistant to thermal treatment. Here, we examined the sporicidal effect of an ohmic heating (OH) system with five sequential electric fields and compared it with that of conventional heating. Apple juice product (50kg) inoculated with A. acidoterrestris spores were subjected to OH (electric field strength=26.7V/cm; frequency=25kHz) at 85–100°C for 30–90s. The effect of conventional heating was also examined under these conditions. OH treatment at 100°C for 30s resulted in total inactivation of the inoculum, with no recovery of viable cells (initial population=4.8–4.9logCFU/ml), whereas 3.6–4.9logCFU/ml of the spores survived conventional heating. OH did not alter the quality (°Brix, color, and pH) of commercial apple juice (p >0.05). These results suggest that the OH system is superior to conventional heating for rapid sterilization (30s) of apple juice to assure microbiological quality in the absence of chemical additives.

      PubDate: 2017-02-17T07:32:27Z
      DOI: 10.1016/j.ijfoodmicro.2017.01.002
      Issue No: Vol. 246 (2017)
       
  • Drying and decontamination of raw pistachios with sequential infrared
           drying, tempering and hot air drying
    • Authors: Chandrasekar Venkitasamy; Maria T. Brandl; Bini Wang; Tara H. McHugh; Ruihong Zhang; Zhongli Pan
      Pages: 85 - 91
      Abstract: Publication date: 4 April 2017
      Source:International Journal of Food Microbiology, Volume 246
      Author(s): Chandrasekar Venkitasamy, Maria T. Brandl, Bini Wang, Tara H. McHugh, Ruihong Zhang, Zhongli Pan
      Pistachio nuts have been associated with outbreaks of foodborne disease and the industry has been impacted by numerous product recalls due to contamination with Salmonella enterica. The current hot air drying of pistachios has low energy efficiency and drying rates, and also does not guarantee the microbial safety of products. In the study described herein, dehulled and water-sorted pistachios with a moisture content (MC) of 38.14% (wet basis) were dried in a sequential infrared and hot air (SIRHA) drier to <9% MC. The decontamination efficacy was assessed by inoculating pistachios with Enterococcus faecium, a surrogate of Salmonella enterica used for quality control in the almond industry. Drying with IR alone saved 105min (34.4%) of drying time compared with hot air drying. SIRHA drying of pistachios for 2h with infrared (IR) heat followed by tempering at a product temperature of 70°C for 2h and then by hot air drying shortened the drying time by 40min (9.1%) compared with drying by hot air only. This SIRHA method also reduced the E. faecium cell population by 6.1-logCFU/g kernel and 5.41-logCFU/g shell of pistachios. The free fatty acid contents of SIRHA dried pistachios were on par with that of hot air dried samples. Despite significant differences in peroxide values (PV) of pistachio kernels dried with the SIRHA method compared with hot air drying at 70°C, the PV were within the permissible limit of 5Meq/kg for edible oils. Our findings demonstrate the efficacy of SIRHA drying in achieving simultaneous drying and decontamination of pistachios.

      PubDate: 2017-02-25T07:31:30Z
      DOI: 10.1016/j.ijfoodmicro.2017.02.005
      Issue No: Vol. 246 (2017)
       
  • Development of quantitative real-time PCR for detection and enumeration of
           Enterobacteriaceae
    • Authors: Hajime Takahashi; Rumi Saito; Satoko Miya; Yuichiro Tanaka; Natsumi Miyamura; Takashi Kuda; Bon Kimura
      Pages: 92 - 97
      Abstract: Publication date: 4 April 2017
      Source:International Journal of Food Microbiology, Volume 246
      Author(s): Hajime Takahashi, Rumi Saito, Satoko Miya, Yuichiro Tanaka, Natsumi Miyamura, Takashi Kuda, Bon Kimura
      The family Enterobacteriaceae, members of which are widely distributed in the environment, includes many important human pathogens. In this study, a rapid real-time PCR method targeting rplP, coding for L16 protein, a component of the ribosome large subunit, was developed for enumerating Enterobacteriaceae strains, and its efficiency was evaluated using naturally contaminated food products. The rplP-targeted real-time PCR amplified Enterobacteriaceae species with Ct values of 14.0–22.8, whereas the Ct values for non-Enterobacteriaceae species were >30, indicating the specificity of this method for the Enterobacteriaceae. Using a calibration curve of Ct=−3.025 (log CFU/g)+37.35, which was calculated from individual plots of the cell numbers in different concentrations of 5 Enterobacteriaceae species, the rplP-targeted real-time PCR was applied to 51 food samples. A <1log difference between the real-time PCR and culture methods was obtained in a majority of the food samples (81.8%), with good correlation (r 2 =0.8285). This study demonstrated that the rplP-targeted real-time PCR method could detect and enumerate Enterobacteriaceae species in foods rapidly and accurately, and therefore, it can be used for the microbiological risk analysis of foods.

      PubDate: 2017-03-04T14:39:21Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.015
      Issue No: Vol. 246 (2017)
       
  • A novel aptasensor for the colorimetric detection of S. typhimurium based
           on gold nanoparticles
    • Authors: Xiaoyuan Ma; Liangjing Song; Nixin Zhou; Yu Xia; Zhouping Wang
      Pages: 1 - 5
      Abstract: Publication date: 20 March 2017
      Source:International Journal of Food Microbiology, Volume 245
      Author(s): Xiaoyuan Ma, Liangjing Song, Nixin Zhou, Yu Xia, Zhouping Wang
      A simple, fast and convenient colorimetric aptasensor was fabricated for the detection of Salmonella typhimurium (S. typhimurium) which was based on the color change effect of gold nanoparticles (GNPs). S. typhimurium is one of the most common causes of food-associated disease. Aptamers with specific recognition toward S. typhimurium was modified to the surface of prepared GNPs. They play a role for the protection of GNPs from aggregation toward high concentrations of NaCl. With the addition of S. typhimurium, aptamers preferably combined to S. typhimurium and the protection effect was broken. With more S. typhimurium, more aptamers detached from GNPs. In such a situation, the exposed GNPs would aggregated to some extent with the addition of NaCl. The color changed from red, purple to blue which could be characterized by UV–Vis spectrophotometer. The absorbance spectra of GNPs redshifted constantly and the intensity ratio of A700/A521 changed regularly. This could be calculated for the basis of quantitative detection of S. typhimurium from 102 cfu/mL to 107 cfu/mL. The obtained linear correlation equation was y=0.1946x–0.2800 (R2 =0.9939) with a detection limit as low as 56cfu/mL. This method is simple and rapid, results in high sensitivity and specificity, and can be used to detect actual samples.

      PubDate: 2017-01-23T02:51:10Z
      DOI: 10.1016/j.ijfoodmicro.2016.12.024
      Issue No: Vol. 245 (2017)
       
  • Occurrence of Arcobacter spp. and correlation with the bacterial indicator
           of faecal contamination Escherichia coli in bivalve molluscs from the
           Central Adriatic, Italy
    • Authors: Francesca Leoni; Serena Chierichetti; Sabrina Santarelli; Giulia Talevi; Laura Masini; Chiara Bartolini; Elena Rocchegiani; M. Naceur Haouet; Donatella Ottaviani
      Pages: 6 - 12
      Abstract: Publication date: 20 March 2017
      Source:International Journal of Food Microbiology, Volume 245
      Author(s): Francesca Leoni, Serena Chierichetti, Sabrina Santarelli, Giulia Talevi, Laura Masini, Chiara Bartolini, Elena Rocchegiani, M. Naceur Haouet, Donatella Ottaviani
      A total of 162 samples of bivalve molluscs (45 mussels and 117 clams) collected between December 2012 and 2014 from harvesting areas of the Central Adriatic were analysed by a culturing method for the presence of Arcobacter spp. Species identification was performed by PCR and sequencing analysis of a fragment of the rpoB gene. Overall, Arcobacter species were detected in 30% of samples, specifically 33% clams and 22% mussels. A. butzleri was the most common species (20% of the samples), followed by A. cryaerophilus (9%) and A. skirrowii (1%). A seasonal association of A. butzleri contamination was detected. A. butzleri was significantly more commonly recovered from samples collected during the winter-spring period (29%) than from those of the summer-autumn (8%). A. cryaerophilus was cultured from 6% to 11% of the samples collected in summer-autumn and winter-spring, respectively, but these differences were not statistically significant. A. skirrowii was recovered from a sample of mussels harvested in May 2014. To identify associations between the occurrence of Arcobacter spp. and E. coli levels, samples were divided into groups generating results with E. coli at >230MPN/100g and E. coli at ≤230MPN/100g, the latter corresponding to EU microbiological criteria allowed for live bivalve molluscs at retail level. A. butzleri was significantly more commonly detected in samples with higher E. coli levels (48%) than in those with lower levels of E. coli (10%), providing evidence for considering E. coli as an index organism for A. butzleri contamination in bivalve molluscs.

      PubDate: 2017-01-23T02:51:10Z
      DOI: 10.1016/j.ijfoodmicro.2017.01.006
      Issue No: Vol. 245 (2017)
       
  • Validation of test portion pooling for Salmonella spp. detection in foods
    • Authors: David Tomás Fornés; Wendy McMahon; Julie Moulin; Adrianne Klijn
      Pages: 13 - 21
      Abstract: Publication date: 20 March 2017
      Source:International Journal of Food Microbiology, Volume 245
      Author(s): David Tomás Fornés, Wendy McMahon, Julie Moulin, Adrianne Klijn
      Pathogen monitoring programs play a crucial role in the verification of the effectiveness of implemented hygiene control measures. Sampling and testing procedures included in pathogen monitoring involve the analysis of multiple test portions where all samples must be negative for the presence of pathogens for a certain test portion size. Many food safety programs require increased testing due to the risks that a pathogen may be present. Analyzing more than one test portion could prove to be expensive and labor intensive. When more than one test portion for a specified food item is to be tested, the test portions could be combined to form a pooled test portion to reduce laboratory workload, costs of reagents and further confirmatory steps, but only when evidence is available that pooling does not affect on the number of false negative results for different matrices. This study has been performed to demonstrate the equivalence of test portion pooling for Salmonella detection with five different methods using cultural, ELISA and Real Time PCR technologies. Twenty-three (23) different food items including confectionary products, meal components, infant formula, pet food and powdered beverages were validated. Other complementary parameters like impact of minimum and maximum incubation time for pre-enrichment, temperature profile, pH and Salmonella concentration after the pre-enrichment and background flora have also been considered in the study. The results showed that pooling test portions up to 375g for Salmonella detection is valid for the methods that were tested. Relative level of detection (RLOD50) values for 22 of the food items tested were acceptable (i.e. lower than 2.5) when comparing the reference sample size (25g) against the alternative pooled sample size (375g), provided the enrichment broth was pre-warmed and maximum incubation time is respected.

      PubDate: 2017-01-23T02:51:10Z
      DOI: 10.1016/j.ijfoodmicro.2017.01.005
      Issue No: Vol. 245 (2017)
       
  • Atmospheric pressure plasma jet treatment of Salmonella Enteritidis
           inoculated eggshells
    • Authors: Maike Moritz; Claudia Wiacek; Martin Koethe; Peggy G. Braun
      Pages: 22 - 28
      Abstract: Publication date: 20 March 2017
      Source:International Journal of Food Microbiology, Volume 245
      Author(s): Maike Moritz, Claudia Wiacek, Martin Koethe, Peggy G. Braun
      Contamination of eggshells with Salmonella Enteritidis remains a food safety concern. In many cases human salmonellosis within the EU can be traced back to raw or undercooked eggs and egg products. Atmospheric pressure plasma is a novel decontamination method that can reduce a wide range of pathogens. The aim of this work was to evaluate the possibility of using an effective short time cold plasma treatment to inactivate Salmonella Enteritidis on the eggshell. Therefore, artificially contaminated eggshells were treated with an atmospheric pressure plasma jet under different experimental settings with various exposure times (15–300s), distances from the plasma jet nozzle to the eggshell surface (5, 8 or 12mm), feed gas compositions (Ar, Ar with 0.2, 0.5 or 1.0% O2), gas flow rates (5 and 7slm) and different inoculations of Salmonella Enteritidis (101–106 CFU/cm2). Atmospheric pressure plasma could reduce Salmonella Enteritidis on eggshells significantly. Reduction factors ranged between 0.22 and 2.27 log CFU (colony-forming units). Exposure time and, particularly at 104 CFU/cm2 inoculation, feed gas had a major impact on Salmonella reduction. Precisely, longer exposure times led to higher reductions and Ar as feed gas was more effective than ArO2 mixtures.

      PubDate: 2017-01-23T02:51:10Z
      DOI: 10.1016/j.ijfoodmicro.2017.01.004
      Issue No: Vol. 245 (2017)
       
  • ICFMH Announcment
    • Abstract: Publication date: 17 April 2017
      Source:International Journal of Food Microbiology, Volume 247


      PubDate: 2017-03-21T16:58:51Z
       
  • Prevalence, antimicrobial resistance and multiple-locus variable-number
           tandem-repeat analysis profiles of diarrheagenic Escherichia coli isolated
           from different retail foods
    • Authors: Lili Wang; Hiromi Nakamura; Eriko Kage-Nakadai; Yukiko Hara-Kudo; Yoshikazu Nishikawa
      Abstract: Publication date: Available online 7 March 2017
      Source:International Journal of Food Microbiology
      Author(s): Lili Wang, Hiromi Nakamura, Eriko Kage-Nakadai, Yukiko Hara-Kudo, Yoshikazu Nishikawa
      Diarrheagenic E. coli (DEC) isolates were recovered from local retail markets and the Osaka Municipal Central Wholesale Market in Japan. Retail food samples were collected for analysis in Osaka Japan from 2005 to 2008 and consisted of 32 beef, 28 pork, 20 poultry, 136 fish, 66 fruits and vegetables and 51 ready–to-eat (RTE) food samples. A total of 82 DEC strains were recovered from 64 (19%) food samples with the highest prevalence in poultry (100%, 20/20), followed by pork (54%, 15/28), beef (28%, 9/32), fruits and vegetables (12%, 8/66), fish (6.6%, 9/136) and RTE foods (5.9%, 3/51). Most of the strains belonged to E. coli possessing the enteroaggregative E. coli (EAEC) heat-stable enterotoxin 1 (EAST1) gene (EAST1EC; n =62, P <0.0001) and enteropathogenic E. coli (EPEC; n =16, P <0.01), whereas only 1 strain belonged to Shiga toxin-producing E. coli (STEC), 1 to EAEC and 2 to enterotoxigenic E. coli (ETEC) strains. Of the 82 DEC isolates, 22 O and 13H serogroups were detected, including some specific serogroups (O91, O103, O115, O119, O126, and O157) which have been associated with human diarrheal infections. Phylogenetic group A and B1 were predominant among the DEC isolates. Antimicrobial resistance to tetracycline was most common (49%), followed by nalidixic acid (28%), ampicillin (24%), sulfamethoxazole/trimethoprim (20%), and cephalothin (18%). All isolates were susceptible to aztreonam. Of the resistant strains, 44% (22/50) demonstrated resistance to >3 antimicrobial agents. Isolates resistant to >5 antimicrobials were only found in the meat samples, while isolates from the fruits and vegetables as well as RTE foods showed resistance to only 1 or 2 antimicrobial agents. Sixty one percent of EAST1EC, 56% of EPEC and all of the EAEC and ETEC were resistant to at least 1 antimicrobial agent. Multiple-locus variable-number tandem repeat analysis (MLVA) was used in this study for genotyping of DEC. The 82 isolates collected for this study showed 77 distinct MLVA profiles located among 3 branches. The Simpson's Index of Diversity (D) was 99.9% at its highest. The high diversity of these food strains would suggest their originating from a variety of sources and environments. In conclusion, retail food samples in Japan were contaminated with DEC; EAST1EC, a putative DEC, were detected at high rates in poultry, pork and beef. Isolates resistant to >3 antimicrobials were found only in raw meat and fish. Food animals may act as the reservoir for multi-resistant bacteria. Due to the finding that nearly 1/3 of EAST1EC strains were resistant to >3 antimicrobials, additional surveillance for EAST1EC should be initiated.

      PubDate: 2017-03-09T14:44:54Z
      DOI: 10.1016/j.ijfoodmicro.2017.03.003
       
  • ICFMH Announcment
    • Abstract: Publication date: 4 April 2017
      Source:International Journal of Food Microbiology, Volume 246


      PubDate: 2017-03-04T14:39:21Z
       
 
 
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