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  Subjects -> BIOLOGY (Total: 3003 journals)
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MICROBIOLOGY (256 journals)                  1 2 | Last

Showing 1 - 200 of 256 Journals sorted alphabetically
Acta Microbiologica et Immunologica Hungarica     Full-text available via subscription   (Followers: 5)
Acta Neurobiologiae Experimentalis     Open Access  
Addiction Genetics     Open Access   (Followers: 7)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 22)
Advances in Microbiology     Open Access   (Followers: 23)
Advances in Molecular Imaging     Open Access   (Followers: 1)
African Journal of Clinical and Experimental Microbiology     Open Access   (Followers: 1)
African Journal of Microbiology Research     Open Access   (Followers: 2)
Algorithms for Molecular Biology     Open Access   (Followers: 4)
American Journal of Infectious Diseases and Microbiology     Open Access   (Followers: 22)
American Journal of Microbiological Research     Open Access   (Followers: 2)
American Journal of Microbiology     Open Access   (Followers: 17)
American Journal of Molecular Biology     Open Access   (Followers: 3)
American Journal of Stem Cell Research     Open Access   (Followers: 4)
Annals of Clinical Microbiology and Antimicrobials     Open Access   (Followers: 8)
Annals of Microbiology     Hybrid Journal   (Followers: 10)
Annual Review of Microbiology     Full-text available via subscription   (Followers: 40)
Antimicrobial Agents and Chemotherapy     Hybrid Journal   (Followers: 25)
Antiviral Research     Hybrid Journal   (Followers: 7)
Applied and Environmental Microbiology     Hybrid Journal   (Followers: 45)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 17)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 62)
Aquatic Microbial Ecology     Hybrid Journal   (Followers: 4)
Archives of Microbiology     Hybrid Journal   (Followers: 8)
Avicenna Journal of Clinical Microbiology and Infection     Open Access   (Followers: 2)
Bangladesh Journal of Medical Microbiology     Open Access   (Followers: 2)
Beneficial Microbes     Full-text available via subscription   (Followers: 2)
Bio-Research     Full-text available via subscription   (Followers: 2)
BioArchitecture     Full-text available via subscription  
Bioethanol     Open Access  
Biomaterials Science     Full-text available via subscription   (Followers: 10)
BioMolecular Concepts     Hybrid Journal   (Followers: 2)
Biomolecular Detection and Quantification     Open Access  
Biomolecules     Open Access   (Followers: 2)
Biotechnology and Molecular Biology Reviews     Open Access   (Followers: 1)
BMC Microbiology     Open Access   (Followers: 11)
Brazilian Journal of Microbiology     Open Access   (Followers: 3)
Canadian Journal of Infectious Diseases and Medical Microbiology     Open Access   (Followers: 4)
Canadian Journal of Microbiology     Hybrid Journal   (Followers: 5)
Cell Biology : Research & Therapy     Hybrid Journal   (Followers: 5)
Cell Host & Microbe     Full-text available via subscription   (Followers: 19)
Cell Medicine     Open Access   (Followers: 4)
Cell Regeneration     Open Access   (Followers: 1)
Cell Stem Cell     Full-text available via subscription   (Followers: 34)
CellBio     Open Access  
Cells     Open Access   (Followers: 2)
Cellular & Molecular Immunology     Hybrid Journal   (Followers: 13)
Cellular and Molecular Biology Letters     Open Access   (Followers: 1)
Cellular and Molecular Life Sciences (CMLS)     Hybrid Journal   (Followers: 5)
Cellular Microbiology     Hybrid Journal   (Followers: 9)
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: 8)
Clinical Microbiology Reviews     Hybrid Journal   (Followers: 17)
Comparative Immunology, Microbiology and Infectious Diseases     Hybrid Journal   (Followers: 11)
Computational Molecular Bioscience     Open Access   (Followers: 2)
Critical Reviews in Microbiology     Hybrid Journal   (Followers: 14)
Current Clinical Microbiology Reports     Hybrid Journal   (Followers: 2)
Current Issues in Molecular Biology     Open Access   (Followers: 3)
Current Microbiology     Hybrid Journal   (Followers: 13)
Current Molecular Biology Reports     Hybrid Journal   (Followers: 1)
Current Molecular Imaging     Hybrid Journal  
Current Opinion in Microbiology     Hybrid Journal   (Followers: 32)
Current Tissue Engineering     Hybrid Journal   (Followers: 2)
Current Topics in Microbiology and Immunology     Hybrid Journal   (Followers: 12)
Diagnostic Microbiology and Infectious Disease     Hybrid Journal   (Followers: 9)
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: 20)
Environmental Microbiology Reports     Hybrid Journal   (Followers: 6)
Enzyme and Microbial Technology     Hybrid Journal   (Followers: 13)
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: 5)
Fems Microbiology Ecology     Hybrid Journal   (Followers: 9)
Fems Microbiology Letters     Hybrid Journal   (Followers: 20)
Fems Microbiology Reviews     Hybrid Journal   (Followers: 25)
Fermentation     Open Access   (Followers: 1)
Folia Histochemica et Cytobiologica     Open Access  
Folia Microbiologica     Hybrid Journal   (Followers: 1)
Food Microbiology     Hybrid Journal   (Followers: 17)
Frontiers in Cell and Developmental Biology     Open Access   (Followers: 5)
Frontiers in Cellular and Infection Microbiology     Open Access   (Followers: 3)
Frontiers in Cellular Neuroscience     Open Access   (Followers: 8)
Frontiers in Microbiology     Open Access   (Followers: 14)
Frontiers in Molecular Neuroscience     Open Access   (Followers: 5)
Future Microbiology     Hybrid Journal   (Followers: 5)
Future Virology     Hybrid Journal   (Followers: 8)
Gene Expression     Full-text available via subscription  
Genetics and Molecular Research     Open Access   (Followers: 4)
Geomicrobiology Journal     Hybrid Journal   (Followers: 3)
Gut Microbes     Full-text available via subscription   (Followers: 8)
IAWA Journal     Hybrid Journal   (Followers: 1)
Indian Journal of Microbiology     Hybrid Journal   (Followers: 2)
Indian Journal of Pathology and Microbiology     Open Access   (Followers: 1)
Infection Ecology & Epidemiology     Open Access   (Followers: 5)
Inside the Cell     Open Access  
International Journal of Antimicrobial Agents     Hybrid Journal   (Followers: 9)
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: 13)
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: 4)
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: 15)
Journal of Bacteriology     Hybrid Journal   (Followers: 29)
Journal of Basic Microbiology     Hybrid Journal   (Followers: 3)
Journal of Biochemistry and Molecular Biology Research     Open Access  
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: 2)
Journal of Brewing and Distilling     Open Access   (Followers: 2)
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: 31)
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: 5)
Journal of General and Molecular Virology     Open Access   (Followers: 1)
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: 16)
Journal of Medical Microbiology     Full-text available via subscription   (Followers: 5)
Journal of Microbiological Methods     Hybrid Journal   (Followers: 3)
Journal of Microbiology     Hybrid Journal   (Followers: 8)
Journal of Microbiology and Antimicrobials     Open Access   (Followers: 2)
Journal of Microbiology Research     Open Access   (Followers: 6)
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: 14)
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: 2)
Journal of Plant Pathology & Microbiology     Open Access   (Followers: 1)
Journal of Proteome Science and Computational Biology     Open Access  
Journal of Regenerative Medicine and Tissue Engineering     Open Access   (Followers: 4)
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: 3)
Journal of Tropical Microbiology and Biotechnology     Full-text available via subscription  
Jundishapur Journal of Microbiology     Open Access  
Letters In Applied Microbiology     Hybrid Journal   (Followers: 7)
Macrophage     Open Access  
MAP Kinase     Open Access  
Medical Mycology     Open Access   (Followers: 4)
Memórias do Instituto Oswaldo Cruz     Open Access  
Methods in Molecular Biology     Hybrid Journal   (Followers: 18)
Microbes and Health     Open Access   (Followers: 1)
Microbes and Infection     Full-text available via subscription   (Followers: 5)
Microbial Biotechnology     Open Access   (Followers: 9)
Microbial Cell Factories     Open Access   (Followers: 7)
Microbial Drug Resistance     Hybrid Journal   (Followers: 4)
Microbial Ecology     Hybrid Journal   (Followers: 10)
Microbial Ecology in Health and Disease     Open Access   (Followers: 1)
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: 14)
Microbiology (SGM)     Full-text available via subscription   (Followers: 18)
Microbiology and Immunology     Hybrid Journal   (Followers: 10)
Microbiology and Molecular Biology Reviews     Hybrid Journal   (Followers: 25)
Microbiology Australia     Hybrid Journal  
Microbiology Discovery     Open Access   (Followers: 2)
Microbiology Indonesia     Open Access  
Microbiology Research     Open Access   (Followers: 7)
MicrobiologyOpen     Open Access   (Followers: 2)
Microbiome     Hybrid Journal   (Followers: 9)
Microbiome Science and Medicine     Open Access   (Followers: 3)
Microorganisms     Open Access   (Followers: 2)
MicroRNA     Hybrid Journal   (Followers: 1)
Molecular and Cellular Therapies     Open Access  
Molecular Biology and Genetic Engineering     Open Access   (Followers: 2)
Molecular Biology Research Communications     Open Access   (Followers: 1)
Molecular Genetics and Metabolism Reports     Open Access   (Followers: 3)
Molecular Genetics, Microbiology and Virology     Hybrid Journal   (Followers: 7)
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: 4)
Molecular Microbiology     Hybrid Journal   (Followers: 32)
Molecular Neuropsychiatry     Full-text available via subscription  
Molecular Oral Microbiology     Partially Free   (Followers: 3)

        1 2 | Last

Journal Cover International Journal of Food Microbiology
  [SJR: 1.64]   [H-I: 142]   [13 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0168-1605
   Published by Elsevier Homepage  [3043 journals]
  • Checking the detail in retail: Occurrence of Cryptosporidium and Giardia
           on vegetables sold across different counters in Chandigarh, India
    • Authors: Kjersti Selstad Utaaker; Anil Kumar; Himanshu Joshi; Suman Chaudhary; Lucy J. Robertson
      Abstract: Publication date: 18 December 2017
      Source:International Journal of Food Microbiology, Volume 263
      Author(s): Kjersti Selstad Utaaker, Anil Kumar, Himanshu Joshi, Suman Chaudhary, Lucy J. Robertson
      Fresh produce has been recognized as a vehicle of infection for protozoan parasites, particularly Cryptosporidium, and, to a lesser extent, Giardia. For both parasites, outbreaks associated with fresh produce have been documented. Although documented outbreaks tend to be from industrialized countries, contamination of fresh produce with these parasites is a global issue. In developing countries, infections with these parasites are often endemic in the community, and basic infrastructure and hygiene measures may be inadequate, thus the likelihood of contamination of fresh produce with these parasites may be higher. Realization of the importance of this transmission route comes against a backdrop of raw salads and more Western culinary habits gaining a foothold, and fresh produce being encouraged as part of the diet due to their associated health benefits. However, if consumption of uncooked fresh produce is going to increase its market sector in India, it is important that it is safe. In this study, various types of fresh produce obtained from three types of vendors in Chandigarh, a major city in Northern India, were analyzed for contamination with Cryptosporidium oocysts and Giardia cysts using a method that has been previously validated in inter-laboratory spiking experiments. A total of 284 samples of different fresh produce items were analyzed, obtained from the different retailers situated in different societal layers of the city. The overall prevalence of contamination of fresh produce with these parasites was just under 11%, with 6% of the vegetables contaminated with Cryptosporidium oocysts, and 5% with Giardia cysts. Contaminated vegetables included turnip, cabbage, carrot, chili, coriander, cucumber, radishes, and tomatoes. Molecular analyses identified contamination with Cryptosporidium parvum and Giardia duodenalis of Assemblage A and Assemblage D, indicating that contamination from animals may be of relevance. Although the prevalence of contamination is similar to those reported in previous studies, the levels of contamination on some items of fresh produce were relatively high. Although the different socioeconomic areas of Chandigarh from which the samples were obtained was not associated with likelihood of contamination, fresh produce from supermarkets had heavier contamination with Cryptosporidium oocysts than fresh produce purchased through other sales outlets. The results are discussed in relation to the fresh produce chain and sales models in Chandigarh, both in terms of where contamination may occur and the potential importance of fresh produce as a transmission vehicle.

      PubDate: 2017-10-08T06:18:06Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.020
      Issue No: Vol. 263 (2017)
       
  • Antimicrobial edible coatings and films from micro-emulsions and their
           food applications
    • Authors: Mingming Guo; Madhav P. Yadav; Tony Z. Jin
      Pages: 9 - 16
      Abstract: Publication date: 18 December 2017
      Source:International Journal of Food Microbiology, Volume 263
      Author(s): Mingming Guo, Madhav P. Yadav, Tony Z. Jin
      This study focused on the use of antimicrobial edible coatings and films from micro-emulsions to reduce populations of foodborne pathogens in foods. Corn-Bio-fiber gum (C-BFG) was used as an emulsifier with chitosan. Allyl isothiocyanate (AIT) and lauric arginate ester (LAE) served as antimicrobials. Micro-emulsions were obtained from a solution consisting of 1% chitosan, 0.5% C-BFG, and 1–4% AIT or LAE which was subject to high pressure homogenization (HPH) processing at 138MPa for 3cycles. Coatings and films produced from the micro-emulsions had micro-pores with sizes ranging from 100 to 300nm and micro-channels that hold antimicrobials effectively and facilitate the release of antimicrobials from the center to the surface of the films or coatings, thus enhancing their antimicrobial efficacy. The coatings and films with 1% AIT reduced populations of Listeria innocua by over 5, 2, and 3 log CFU in culture medium (Tryptic soy broth, TSB), ready-to-eat meat, and strawberries, respectively. The coatings and films with 1% LAE reduced populations of Escherichia coli O157:H7 and Salmonella spp. by over 5 and 2 log CFU in TSB and strawberries, respectively. This study provides an innovative approach for the development of effective antimicrobial materials to reduce food borne pathogenic contaminants on ready-to-eat meat, strawberries, or other food.

      PubDate: 2017-10-14T06:24:12Z
      DOI: 10.1016/j.ijfoodmicro.2017.10.002
      Issue No: Vol. 263 (2017)
       
  • Salmonella survival during thermal dehydration of fresh garlic and storage
           of dehydrated garlic products
    • Authors: Hongmei Zhang; Yan Qi; Lei Wang; Shaokang Zhang; Xiangyu Deng
      Pages: 26 - 31
      Abstract: Publication date: 18 December 2017
      Source:International Journal of Food Microbiology, Volume 263
      Author(s): Hongmei Zhang, Yan Qi, Lei Wang, Shaokang Zhang, Xiangyu Deng
      Salmonella survival was characterized and modeled during thermal dehydration of fresh garlic and storage of dehydrated garlic products. In our experiments that simulated commercial dehydration processing at 80±5°C, moderate level of Salmonella contamination (4–5logCFU/g) on fresh garlic was reduced below the enumeration limit (1.7logCFU/g) after 4.5h of dehydration and not detectable by culture enrichment after 7h. With high level of contamination (7–8logCFU/g), the Salmonella population persisted at 3.6logCFU/g after 8h of processing. By increasing the dehydration temperature to 90±5°C, the moderate and high levels of initial Salmonella load on fresh garlic dropped below the enumeration limit after 1.5 and 3.75h of processing and became undetectable by culture enrichment after 2.5 and 6h, respectively. During the storage of dried garlic products, Salmonella was not able to grow under all tested combinations of temperature (25 and 35°C) and water activity (0.56–0.98) levels, suggesting active inhibition. Storage temperature played a primary role in determining Salmonella survival on dehydrated garlic flakes. Under a typical storage condition at 25°C and ambient relative humidity, Salmonella could persist over months with the population gradually declining (4.3 log reduction over 88days). Granular size of dehydrated garlic had an impact on Salmonella survival, with better survival of the pathogen observed in smaller granules. At the early stage of dehydrated garlic storage (until 7days), rising water activity appeared to initially promote but then inhibited Salmonella survival, resulting in a water activity threshold at 0.73 where Salmonella displayed strongest persistence. However, this phenomenon was less apparent during extended storage (after 14days).

      PubDate: 2017-10-14T06:24:12Z
      DOI: 10.1016/j.ijfoodmicro.2017.10.010
      Issue No: Vol. 263 (2017)
       
  • Virulence genotypes and antimicrobial susceptibility patterns of
           Arcobacter butzleri isolated from seafood and its environment
    • Authors: Srinu Rathlavath; Vandita Kohli; Asem Sanjit Singh; Manjusha Lekshmi; Gayatri Tripathi; Sanath Kumar; Binaya Bhusan Nayak
      Pages: 32 - 37
      Abstract: Publication date: 18 December 2017
      Source:International Journal of Food Microbiology, Volume 263
      Author(s): Srinu Rathlavath, Vandita Kohli, Asem Sanjit Singh, Manjusha Lekshmi, Gayatri Tripathi, Sanath Kumar, Binaya Bhusan Nayak
      Arcobacter butzleri is an emerging pathogen isolated from animals, food and the environment. In this study, 147 A. butzleri isolated from seafood and the coastal environment were tested for the presence of ten putative virulence genes (cadF, cj1349, ciaB, mviN, pldA, tlyA, hecA, hecB, irgA, iroE) and antimicrobial susceptibilities. Majority of the isolates harbored mviN (100%), cj1349 (97.2%), ciaB (95.9%), tlyA (91.8%), pldA (91.1%) and cadF (89.7%). Lower detection rates were observed for hecA (10.8%), hecB (19%), iroE (12.9%) and irgA (17.6%). Three A. butzleri isolates harbored all ten virulence genes. The occurrence of cj1349, ciaB, pldA, tlyA and hecA genes was significantly different (P ≤0.05) among the isolates from different sources. All (100%) A. butzleri isolates were resistant to vancomycin, cephalothin, cefoxitin and sulphamethizole and susceptible to polymyxin-B, kanamycin, streptomycin, gentamicin, tetracycline and imipenem. Resistance to clinically important antibiotics such as cefotaxime (99.3%), ceftazidime (87.7%), nalidixic acid (70.7%), ampicillin (72.1%), ertapenem and amoxicillin-clavulanic acid (41.9%) was observed in A. butzleri from the environment. The isolates were highly susceptible to norfloxacin (97.9%) and colistin (97.2%), followed by ciprofloxacin (88.4%), meropenem (74.8%), chloramphenicol (72.7%) and erythromycin (69.3%). A. butzleri from different sources were not significantly different with respect to their antimicrobial susceptibility patterns. Multidrug resistance was observed in 66 (81.4%) isolates from fish, 29 (72.5%) isolates from shellfish and 17 (65.3%) isolates from coastal water. A. butzleri harboring virulence genes and resistance to multiple antibiotics found in seafood could be a potential health risk to seafood handlers and consumers. Continuous monitoring of seafood for potentially pathogenic A. butzleri is important to understand the evolution of antibiotic resistance in this emerging food pathogen and to determine the antimicrobial therapy regimen in the event of food-borne A. butzleri infections.

      PubDate: 2017-10-14T06:24:12Z
      DOI: 10.1016/j.ijfoodmicro.2017.10.005
      Issue No: Vol. 263 (2017)
       
  • Occurrence of transferable antibiotic resistances in commercialized
           ready-to-eat mealworms (Tenebrio molitor L.)
    • Authors: Andrea Osimani; Federica Cardinali; Lucia Aquilanti; Cristiana Garofalo; Andrea Roncolini; Vesna Milanović; Marina Pasquini; Stefano Tavoletti; Francesca Clementi
      Pages: 38 - 46
      Abstract: Publication date: 18 December 2017
      Source:International Journal of Food Microbiology, Volume 263
      Author(s): Andrea Osimani, Federica Cardinali, Lucia Aquilanti, Cristiana Garofalo, Andrea Roncolini, Vesna Milanović, Marina Pasquini, Stefano Tavoletti, Francesca Clementi
      The present study aimed to assess the occurrence of transferable determinants conferring resistance to tetracyclines, macrolide-lincosamide-streptogramin B, vancomycin, beta-lactams, and aminoglycosides in 40 samples of commercialized edible mealworms (Tenebrio molitor L.) purchased from European Union (EU) and non-EU producers. A high prevalence of tet(K) was observed in all of the samples assayed, with percentages of PCR-based positivity that ranged from 80% (samples from Thailand) to 100% (samples from the Netherlands, Belgium and France). For macrolides, erm(B) prevailed, being detected in 57.5% of the samples assayed, whereas erm(A) and erm(C) were detected with lower frequencies. Genes for resistance to vancomycin were only detected in samples produced in France and Belgium, with 90% and 10% of the samples being positive for vanA, respectively. Beta-lactamase genes were found with low occurrence, whereas the gene aac-aph, conferring high resistance to aminoglycosides, was found in 40% of the samples produced in the Netherlands and Belgium and 20% of the samples produced in Thailand. The results of Principal Coordinate Analysis and Principal Component Analysis depicted a clean separation of the samples collected from the four producers based on the distribution of the 12 AR determinants considered. Given the growing interest on the use of mealworms as a novel protein source, AR detection frequencies found in the present study suggest further investigation into the use of antibiotics during rearing of this insect species and more extensive studies focused on the factors that can affect the diffusion of transferable ARs in the production chain. Until such studies are completed, prudent use of antibiotics during rearing of edible insects is recommended.

      PubDate: 2017-10-14T06:24:12Z
      DOI: 10.1016/j.ijfoodmicro.2017.10.009
      Issue No: Vol. 263 (2017)
       
  • Evaluation of the Gauss-Eyring model to predict thermal inactivation of
           micro-organisms at short holding times
    • Authors: R.A.H. Timmermans; H.C. Mastwijk; M.N. Nierop Groot; M.A.J.S. Van Boekel
      Pages: 47 - 60
      Abstract: Publication date: 18 December 2017
      Source:International Journal of Food Microbiology, Volume 263
      Author(s): R.A.H. Timmermans, H.C. Mastwijk, M.N. Nierop Groot, M.A.J.S. Van Boekel
      Application of mild (non)-thermal processing technologies have received considerable interest as alternative to thermal pasteurisation, because of its shorter holding time and lower temperature aiming for an improved product quality. To understand and develop these alternative technologies, like pulsed electric fields, a proper comparison between the conventional thermal and alternative process is necessary. Up to recent, no suitable models were available to predict the inactivation of micro-organisms by a thermal process at a chosen short holding time, due to non-linearity. The recently developed Gauss-Eyring model with two variables temperature and time has the properties to be a suitable model to apply for short holding times, and was tested for this purpose. Therefore, this study aims to validate if the Gauss-Eyring model can be used to describe non-linear isothermal (a fixed temperature with varying holding time) and isotime (a fixed holding time with varying temperature) thermal inactivation data, and if it is a suitable model to predict the thermal inactivation as a function of temperature for short holding times. Inactivation data of Escherichia coli, Listeria monocytogenes, Lactobacillus plantarum, Salmonella Senftenberg and Saccharomyces cerevisiae in orange juice were collected via isothermal and isotime inactivation kinetics. Survival of the tested micro-organisms was modelled with the Gauss-Eyring model, which contains three parameters σ, Tr and Z. The transition of ‘no inactivation’ to ‘inactivation’ (i.e. the ‘shoulder’ in inactivation curves) can be characterised as the temperature-time (T,t) combination where T = Tr − Z · log 10 (t), with Tr as the reference temperature defined for 1s treatment, Z as the temperature needed for a 10-fold increase of decrease of the holding time t, and σ as the temperature width of the distribution. The Gauss-Eyring model fitted well to the experimental data, and revealed different sensitivity for the tested micro-organisms. Based on the parameter estimations, survival curves for the desired short holding times were predicted.

      PubDate: 2017-10-14T06:24:12Z
      DOI: 10.1016/j.ijfoodmicro.2017.10.001
      Issue No: Vol. 263 (2017)
       
  • Effects of processing parameters on the inactivation of Bacillus cereus
           spores on red pepper (Capsicum annum L.) flakes by microwave-combined cold
           plasma treatment
    • Authors: Jung Eun Kim; Hyeon-Son Choi; Dong-Un Lee; Sea C. Min
      Pages: 61 - 66
      Abstract: Publication date: 18 December 2017
      Source:International Journal of Food Microbiology, Volume 263
      Author(s): Jung Eun Kim, Hyeon-Son Choi, Dong-Un Lee, Sea C. Min
      The efficacy of microwave-combined cold plasma treatment (MCPT) for inactivating Bacillus cereus spores contaminating red pepper (Capsicum annum L.) flakes was investigated. The effects of red pepper drying method, particle size, and water activity (aw) were also evaluated at two levels of microwave power (1700 and 2500W/cm2). The inactivation effect of MCPT was higher at higher microwave power. Spore reduction was more effective with vacuum-dried red pepper than far-infrared-dried flakes. A significantly higher level of spore reduction was observed with the red pepper sample with a smaller surface to volume ratio when one surface (exterior surface) was inoculated (p <0.05). Spore reduction by MCPT at high microwave power increased from 1.7 to 2.6logspores/cm2 when the aw of flake increased from 0.4 to 0.9 (p <0.05). MCPT did not change the color of red pepper flakes. MCPT demonstrated potential as a microbial decontaminating technology for red pepper flakes.

      PubDate: 2017-10-14T06:24:12Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.014
      Issue No: Vol. 263 (2017)
       
  • In response to Tomás, D. et al. (2017). Validation of test portion
           pooling for Salmonella spp. detection in foods. International Journal of
           Food Microbiology, 245: 13–21
    • Authors: Han Joosten; Carol Iversen
      Pages: 1 - 2
      Abstract: Publication date: 4 December 2017
      Source:International Journal of Food Microbiology, Volume 262
      Author(s): Han Joosten, Carol Iversen


      PubDate: 2017-09-24T02:18:52Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.009
      Issue No: Vol. 262 (2017)
       
  • Microbial diversity on commercial eggs as affected by the production
           system. A first approach using PGM
    • Authors: Carmen Neira; Amanda Laca; Adriana Laca; Mario Díaz
      Pages: 3 - 7
      Abstract: Publication date: 4 December 2017
      Source:International Journal of Food Microbiology, Volume 262
      Author(s): Carmen Neira, Amanda Laca, Adriana Laca, Mario Díaz
      A novel DNA-based technique (PGM) has been employed for first time to analyse commercial eggs with the advantage of allowing an exhaustive identification of the microbiota present. Eggs from two different production systems, i.e. a free range system and a cage system, were analysed. Twenty-one and twenty-two phyla were identified on the surface of cage system and free range system eggs, respectively. In both cases, Firmicutes was the dominant phylum (representing around 50% of total phyla), being found families frequently reported to be present in the intestinal microbiota of chickens or hens, such as Clostridiaceae, Ruminococcaceae and Lachnospiraceae. Additionally, other phyla and families not previously described in association with eggshells could also be identified in this work. Most of the potential pathogenic genera associated with eggs (Salmonella, Clostridium, Helicobacter, Pseudomonas and Staphylococcus) showed higher incidence in eggs coming from cage systems than in eggs coming from free range systems, although the abundance of these genera were very low in both cases (<5% of total bacteria).

      PubDate: 2017-09-30T19:37:08Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.008
      Issue No: Vol. 262 (2017)
       
  • Effects of the predominant bacteria from meju and doenjang on the
           production of volatile compounds during soybean fermentation
    • Authors: Do-Won Jeong; Sojeong Heo; Bitnara Lee; Hyundong Lee; Keuncheol Jeong; Jae-Young Her; Kwang-Geun Lee; Jong-Hoon Lee
      Pages: 8 - 13
      Abstract: Publication date: Available online 19 September 2017
      Source:International Journal of Food Microbiology
      Author(s): Do-Won Jeong, Sojeong Heo, Bitnara Lee, Hyundong Lee, Keuncheol Jeong, Jae-Young Her, Kwang-Geun Lee, Jong-Hoon Lee
      We inoculated five starter candidates, Enterococcus faecium, Tetragenococcus halophilus, Bacillus licheniformis, Staphylococcus saprophyticus, and Staphylococcus succinus, into sterilized soybeans to predict their effectiveness for flavor production in fermented soybean foods. All of the starter candidates exhibited sufficient growth and acid production on soybean cultures. Twenty-two volatile compounds, such as acids, alcohols, carbonyls, esters, furans, and pyrazines, were detected from the control and starter candidate-inoculated soybean cultures. Principal component analysis of these volatile compounds concluded that E. faecium and T. halophilus produced a similar profile of volatile compounds to soybeans with no dramatic differences in soybean flavor. B. licheniformis and S. succinus produced the crucial volatile compounds that distinguish the flavor profiles of soybean. During soybean fermentation, phenylmethanol and 2,3,5,6-tetramethylpyrazine were determined as odor notes specific to B. licheniformis and 3-methylbutyl acetate as an odor note specific to S. succinus.

      PubDate: 2017-09-24T02:18:52Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.011
      Issue No: Vol. 262 (2017)
       
  • Biotransformation of soy whey into soy alcoholic beverage by four
           commercial strains of Saccharomyces cerevisiae
    • Authors: Jian-Yong Chua; Yuyun Lu; Shao-Quan Liu
      Pages: 14 - 22
      Abstract: Publication date: 4 December 2017
      Source:International Journal of Food Microbiology, Volume 262
      Author(s): Jian-Yong Chua, Yuyun Lu, Shao-Quan Liu
      Soy whey is a liquid waste stream generated from tofu and soy protein manufacturing, and is commonly disposed of into the drainage system in food industry. Instead of disposing of soy whey as a waste, it could be used to produce alcoholic beverages. This study investigated the feasibility of converting soy whey into soy alcoholic beverage using four commercial Saccharomyces cerevisiae strains as a zero-waste approach to tackle the soy whey disposal issue. The four Saccharomyces yeasts grew by approximately 2logCFU/mL and produced approximately 7–8% (v/v) of ethanol. Isoflavone glucosides were hydrolyzed and transformed into isoflavone aglycones, increasing the antioxidant capacity. New aroma-active volatiles, especially esters and higher alcohols, were produced and imparted fruity and floral notes to the soy alcoholic beverage. Therefore, alcoholic fermentation would serve as a solution toward zero-waste manufacturing by biotransforming soy whey into a world's first novel functional alcoholic beverage naturally enriched with free isoflavones.

      PubDate: 2017-09-30T19:37:08Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.007
      Issue No: Vol. 262 (2017)
       
  • Emergence of Salmonella enterica serovar Indiana and California isolates
           with concurrent resistance to cefotaxime, amikacin and ciprofloxacin from
           chickens in China
    • Authors: Yongxiang Wang; Anyun Zhang; Yongqiang Yang; Changwei Lei; Wei Jiang; Bihui Liu; Hongping Shi; Linghan Kong; Guangyang Cheng; Xiuzhong Zhang; Xin Yang; Hongning Wang
      Pages: 23 - 30
      Abstract: Publication date: 4 December 2017
      Source:International Journal of Food Microbiology, Volume 262
      Author(s): Yongxiang Wang, Anyun Zhang, Yongqiang Yang, Changwei Lei, Wei Jiang, Bihui Liu, Hongping Shi, Linghan Kong, Guangyang Cheng, Xiuzhong Zhang, Xin Yang, Hongning Wang
      The aim of this study was to investigate the prevalence and characterization of Salmonella concerning the poultry industry in China. A total of 170 non-duplicate Salmonella isolates were recovered from the 1540 chicken samples. Among the Salmonella isolates from chickens, the predominant serovars were S. enterica serovar Enteritidis (S. Enteritidis) (49/170, 28.8%), S. enterica serovar Indiana (S. Indiana) (37/170, 21.8%) and S. enterica serovar California (S. California) (34/170, 20.0%). High antimicrobial resistance was observed for ciprofloxacin (68.2%), amikacin (48.2%) and cefotaxime (44.7%). Of particular concerns were the 18 S. Indiana and 17 S. California isolates, which were concurrently resistant to cefotaxime, amikacin and ciprofloxacin. The bla CTX-M genes, 16S rRNA methylase genes (armA, rmtD or rmtC) and five plasmid-mediated quinolone resistance (PMQR) determinants (aac(6′)-Ib-cr, oqxAB, qnrB, qepA and qnrD) were identified in 18 S. Indiana and 17 S. California isolates. To clarify their genetic correlation, pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were further conducted. PFGE profiles showed that the majority of S. Indiana and S. California isolates were clonally unrelated with a standard cut-off of 85%. The results of MLST demonstrated that ST17 and ST40 were the most common ST types in S. Indiana and S. California isolates, respectively. Our findings indicated that the multiple antibiotic resistant S. Indiana and S. California isolates were widespread in chicken in China and might pose a potential threat to public health.

      PubDate: 2017-10-14T06:24:12Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.012
      Issue No: Vol. 262 (2017)
       
  • Food poisoning outbreak in Tokyo, Japan caused by Staphylococcus argenteus
    • Authors: Yasunori Suzuki; Hiroaki Kubota; Hisaya K. Ono; Makiko Kobayashi; Konomi Murauchi; Rei Kato; Akihiko Hirai; Kenji Sadamasu
      Pages: 31 - 37
      Abstract: Publication date: 4 December 2017
      Source:International Journal of Food Microbiology, Volume 262
      Author(s): Yasunori Suzuki, Hiroaki Kubota, Hisaya K. Ono, Makiko Kobayashi, Konomi Murauchi, Rei Kato, Akihiko Hirai, Kenji Sadamasu
      Staphylococcus argenteus is a novel species subdivided from Staphylococcus aureus. Whether this species can cause food poisoning outbreaks is unknown. This study aimed to investigate the enterotoxigenic activities of two food poisoning isolates suspected to be S. argenteus (Tokyo13064 and Tokyo13069). The results for phylogenic trees, constructed via whole genome sequencing, demonstrated that both isolates were more similar to a type strain of S. argenteus (MSHR1132) than any S. aureus strain. Moreover, the representative characteristics of S. argenteus were present in both strains, namely both isolates belong to the CC75 lineage and both lack a crtOPQMN operon. Thus, both were determined to be “S. argenteus.” The compositions of the two isolates' accessory elements differed from those of MSHR1132. For example, the seb-related Staphylococcus aureus pathogenicity island, SaPIishikawa11, was detected in Tokyo13064 and Tokyo13069 but not in MSHR1132. Both isolates were suggested to belong to distinct lineages that branched off from MSHR1132 lineages in terms of accessory elements. Tokyo13064 and Tokyo13069 expressed high levels of s(arg)eb and produced S(arg)EB protein, indicating that both have the ability to cause food poisoning. Our findings suggest that S. argenteus harboring particular accessory elements can cause staphylococcal diseases such as food poisoning, similarly to S. aureus.

      PubDate: 2017-10-14T06:24:12Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.005
      Issue No: Vol. 262 (2017)
       
  • S. Typhimurium virulence changes caused by exposure to different
           non-thermal preservation treatments using C. elegans
    • Authors: María Sanz-Puig; Elena Lázaro; Carmen Armero; Danilo Alvares; Antonio Martínez; Dolores Rodrigo
      Pages: 49 - 54
      Abstract: Publication date: 4 December 2017
      Source:International Journal of Food Microbiology, Volume 262
      Author(s): María Sanz-Puig, Elena Lázaro, Carmen Armero, Danilo Alvares, Antonio Martínez, Dolores Rodrigo
      The aims of this research study were: (i) to postulate Caenorhabditis elegans (C. elegans) as a useful organism to describe infection by Salmonella enterica serovar Typhimurium (S. Typhimurium), and (ii) to evaluate changes in virulence of S. Typhimurium when subjected repetitively to different antimicrobial treatments. Specifically, cauliflower by-product infusion, High Hydrostatic Pressure (HHP), and Pulsed Electric Fields (PEF). This study was carried out by feeding C. elegans with different microbial populations: E. coli OP50 (optimal conditions), untreated S. Typhimurium, S. Typhimurium treated once and three times with cauliflower by-product infusion, S. Typhimurium treated once and four times with HHP and S. Typhimurium treated once and four times with PEF. Bayesian survival analysis was applied to estimate C. elegans lifespan when fed with the different microbial populations considered. Results showed that C. elegans is a useful organism to describe infection by S. Typhimurium because its lifespan was reduced when it was infected. In addition, the application of antimicrobial treatments repetitively generated different responses: when cauliflower by-product infusion and PEF treatment were applied repetitively the virulence of S. Typhimurium was lower than when the treatment was applied once. In contrast, when HHP treatment was applied repetitively, the virulence of S. Typhimurium was higher than when it was applied once. Nevertheless, in all the populations analyzed treated S. Typhimurium had lower virulence than untreated S. Typhimurium.

      PubDate: 2017-10-14T06:24:12Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.006
      Issue No: Vol. 262 (2017)
       
  • Effect of Pseudomonas graminis strain CPA-7 on the ability of Listeria
           monocytogenes and Salmonella enterica subsp. enterica to colonize Caco-2
           cells after pre-incubation on fresh-cut pear
    • Authors: Cyrelys Collazo; Maribel Abadías; Pilar Colás-Medà; María Belén Iglesias; Ana Belén Granado-Serrano; José Serrano; Inmaculada Viñas
      Pages: 55 - 62
      Abstract: Publication date: 4 December 2017
      Source:International Journal of Food Microbiology, Volume 262
      Author(s): Cyrelys Collazo, Maribel Abadías, Pilar Colás-Medà, María Belén Iglesias, Ana Belén Granado-Serrano, José Serrano, Inmaculada Viñas
      To further gain insight into the mechanism by which the biopreservative bacterium Pseudomonas graminis CPA-7 develops its antimicrobial activity, we have examined the effect that the prior interaction stablished by this bacterium and two foodborne pathogens on fresh-cut pear, has on their capacity to colonize human epithelial cells (Caco-2 cell line) which is crucial for establishing infection. CPA-7 inhibited the growth of L. monocytogenes and S. enterica subsp. enterica ser. Enteritidis by 5.5 and 3.1 log10, respectively, after 7d of interaction at 10°C. Furthermore, CPA-7 attenuated the adherence of S. enterica to Caco-2 cells by 0.8 log10 regardless of the pre-adaptation on the fruit. Conversely, the adhesiveness of L. monocytogenes was not influenced by the interaction with the antagonist but it was reduced by 0.5 log10 after incubation on the food matrix. Pathogen-antagonist-food matrix interaction was associated to a significant reduction of the relative invasiveness of both pathogens, by 1.3 log10 in the case of L. monocytogenes and to an undetectable level (below 5CFU/g fruit) for S. enterica. CPA-7 can adhere to and internalize into intestinal epithelium which enables it for competition. Its adherence positively correlates to the multiplicity of infection (MOI) with respect to Caco-2 cells, increasing by 0.6 log10 in an MOI range of 0.1:1 to 100:1. For the same levels of inoculum, internalized cells could only be detected after 7d of pre-adaptation in the fruit (pH4.5–5.0). However, the combination of gastrointestinal digestion and habituation on the fruit resulted in a significant reduction of CPA-7 populations (by 2 log10 more after 7d of incubation than on inoculation day) as well as in the decrease of its adhesiveness (by 0.8 log10) and invasiveness (to undetectable levels).

      PubDate: 2017-09-30T19:37:08Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.003
      Issue No: Vol. 262 (2017)
       
  • Yeast community in traditional Portuguese Serpa cheese by
           culture-dependent and -independent DNA approaches
    • Authors: Maria Teresa P. Gonçalves Dos Santos; María José Benito; María de Guía Córdoba; Nuno Alvarenga; Santiago Ruiz-Moyano Seco de Herrera
      Pages: 63 - 70
      Abstract: Publication date: 4 December 2017
      Source:International Journal of Food Microbiology, Volume 262
      Author(s): Maria Teresa P. Gonçalves Dos Santos, María José Benito, María de Guía Córdoba, Nuno Alvarenga, Santiago Ruiz-Moyano Seco de Herrera
      This study investigated the yeast community present in the traditional Portuguese cheese, Serpa, by culture-dependent and -independent methods. Sixteen batches of Serpa cheeses from various regional industries registered with the Protected Designation of Origin (PDO) versus non-PDO registered, during spring and winter, were used. Irrespective of the producer, the yeast counts were around 5log CFU/g in winter and, overall, were lower in spring. The yeast species identified at the end of ripening (30days), using PCR-RFLP analysis and sequencing of the 26S rRNA, mainly corresponded to Debaryomyces hansenii and Kluyveromyces marxianus, with Candida spp. and Pichia spp. present to a lesser extent. The culture-independent results, obtained using high-throughput sequencing analysis, confirmed the prevalence of Debaryomyces spp. and Kluyveromyces spp. but, also, that Galactomyces spp. was relevant for three of the five producers, which indicates its importance during the early stages of the cheese ripening process, considering it was not found among the dominant viable yeast species. In addition, differences between the identified yeast isolated from cheeses obtained from PDO and non-PDO registered industries, showed that the lack of regulation of the cheese-making practice, may unfavourably influence the final yeast microbiota. The new knowledge provided by this study of the yeast diversity in Serpa cheese, could be used to modify the cheese ripening conditions, to favour desirable yeast species. Additionally, the prevalent yeast isolates identified, Debaryomyces hansenii and Kluyveromyces spp., may have an important role during cheese ripening and in the final sensorial characteristics. Thus, the study of their technological and functional properties could be relevant, in the development of an autochthonous starter culture, to ensure final quality and safety of the cheese.

      PubDate: 2017-09-30T19:37:08Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.013
      Issue No: Vol. 262 (2017)
       
  • Using the agricultural environment to select better surrogates for
           foodborne pathogens associated with fresh produce
    • Authors: Kimberly L. Cook; Ethan C. Givan; Holly M. Mayton; Rohan R. Parekh; Ritchie Taylor; Sharon L. Walker
      Pages: 80 - 88
      Abstract: Publication date: 4 December 2017
      Source:International Journal of Food Microbiology, Volume 262
      Author(s): Kimberly L. Cook, Ethan C. Givan, Holly M. Mayton, Rohan R. Parekh, Ritchie Taylor, Sharon L. Walker
      Despite continuing efforts to reduce foodborne pathogen contamination of fresh produce, significant outbreaks continue to occur. Identification of appropriate surrogates for foodborne pathogens facilitates relevant research to identify reservoirs and amplifiers of these contaminants in production and processing environments. Therefore, the objective of this study was to identify environmental Escherichia coli isolates from manures (poultry, swine and dairy) and surface water sources with properties similar to those of the produce associated foodborne pathogens E. coli O157:H7 and Salmonella enterica serotype Typhimurium. The most similar environmental E. coli isolates were from poultry (n =3) and surface water (n =1) sources. The best environmental E. coli surrogates had cell surface characteristics (zeta potential, hydrophobicity and exopolysaccharide composition) that were similar (i.e., within 15%) to those of S. Typhimurium and/or formed biofilms more often when grown in low nutrient media prepared from lettuce lysates (24%) than when grown on high nutrient broth (7%). The rate of attachment of environmental isolates to lettuce leaves was also similar to that of S. Typhimurium. In contrast, E. coli O157:H7, a commonly used E. coli quality control strain and swine isolates behaved similarly; all were in the lowest 10% of isolates for biofilm formation and leaf attachment. These data suggest that the environment may provide a valuable resource for selection of surrogates for foodborne pathogens.

      PubDate: 2017-09-30T19:37:08Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.017
      Issue No: Vol. 262 (2017)
       
  • Propensity for biofilm formation by aerobic mesophilic and thermophilic
           spore forming bacteria isolated from Chinese milk powders
    • Authors: Faizan A. Sadiq; Steve Flint; Lei Yuan; Yun Li; TongJie Liu; GuoQing He
      Pages: 89 - 98
      Abstract: Publication date: 4 December 2017
      Source:International Journal of Food Microbiology, Volume 262
      Author(s): Faizan A. Sadiq, Steve Flint, Lei Yuan, Yun Li, TongJie Liu, GuoQing He
      Biofilms on the surface of dairy manufacturing plants are potential reservoirs of microbial contamination. These microbial aggregates may harbour pathogenic and spoilage organisms which contaminate dairy products. The biofilm forming capacity of many spore forming isolates of dairy origin has not been given much attention. The present study explored the biofilm forming potential of 148 isolates, comprising mesophilic and thermophilic bacteria, with particular emphasis on Bacillus licheniformis on polystyrene and stainless steel (SS) surfaces. We concluded that only four species are of significance for biofilm development on the surface of SS in the presence of skimmed milk, namely, B. licheniformis, Geobacillus stearothermophilus, Geobacillus thermoleovorans group and Anoxybacillus flavithermus. The maximum number of cells recovered from the biofilms developed on SS coupons in the presence of skimmed milk for these four species was as follows: 4.8, 5.2, 4.5 and 5.3logCFU/cm2, respectively. Number of cells recovered from biofilms on 1cm2 SS coupons increased in the presence of tryptic soy broth (TSB) for all mesophiles including B. licheniformis, while decreased for G. stearothermophilus, G. thermoleovorans group and A. flavithermus. The crystal violet staining assay on polystyrene proved to be inadequate to predict cell counts on SS for the bacteria tested in our trial in the presence of either TSB or skimmed milk. The results support the idea that biofilm formation is an important part of bacterial survival strategy as only the most prevalent isolates from milk powders formed good biofilms on SS in the presence of skimmed milk. Biofilm formation also proved to be a strain-dependent characteristic and interestingly significant variation in biofilm formation was observed within the same RAPD groups of B. licheniformis which supports the previously reported genetic and phenotypic heterogeneity within the same RAPD based groups. The work reported in this manuscript will broaden our knowledge on biofilm formation of a large number of dairy isolates and emphasize strain and substrate dependence.

      PubDate: 2017-09-30T19:37:08Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.015
      Issue No: Vol. 262 (2017)
       
  • Assessment of Salmonella survival in dry-cured Italian salami
    • Authors: S. Bonardi; I. Bruini; L. Bolzoni; P. Cozzolino; M. Pierantoni; F. Brindani; P. Bellotti; M. Renzi; S. Pongolini
      Pages: 99 - 106
      Abstract: Publication date: 4 December 2017
      Source:International Journal of Food Microbiology, Volume 262
      Author(s): S. Bonardi, I. Bruini, L. Bolzoni, P. Cozzolino, M. Pierantoni, F. Brindani, P. Bellotti, M. Renzi, S. Pongolini
      The inactivation of Salmonella during curing of Italian traditional pork salami was investigated. A total of 150 batches of ground raw meat (GRM) used for salami manufacturing by four producers were tested for Salmonella by real-time PCR followed by ISO 6579 cultural confirmation and MPN enumeration. Salami produced with Salmonella positive GRMs were re-tested at the end of their curing period. Aw, pH and NaCl content were also measured. Detection of Salmonella was performed testing both 25 and 50g of the samples. By Real-Time PCR 37% of the GRMs resulted positive, but cultural detection of Salmonella was obtained in 14% of the samples only. Salmonella enumeration ranged from 31 MPN/g to <1.3 MPN/g. The difference between testing 50g and 25g of the samples was statistically significant (p value≤0.01). In particular, ISO-50g detected Salmonella in 100% of all positive samples, vs. 62% of ISO-25g. Salami made of the contaminated GRMs were 29% Salmonella-positive, as most batches of salami produced with Salmonella-positive GRMs resulted negative after regular curing (20–48days). Overall, 13% of salami produced with Salmonella-contaminated GRMs were positive. They belonged to six batches, which turned out negative after prolonged curing ranging between 49 and 86days. Salmonella enumeration in salami ranged from 8.7 MPN/g to <1.3 MPN/g. Unlike GRMs, no significant difference was observed between the ISO-50g and the ISO-25g in detecting Salmonella in cured salami (p value: >0.05). The most common Salmonella serovars in GRMs were Derby (52%), Typhimurium monophasic variant 4, (Barbuti et al., 1993), 12:i:- (19%) and Stanley (10%). Salmonella Derby (56%), London, Branderup, Panama (13%, respectively) and Goldcoast (6%) were most frequent in cured salami. The study showed negative correlation between real-time CT values and cultural confirmation of Salmonella, as well as the importance of sample size for Salmonella detection. Among considered factors with possible effect on the occurrence of Salmonella in salami, statistical analysis revealed a role for aw in salami and for Salmonella load in GRMs, while pH and NaCl content did not significantly affect the probability of finding Salmonella in dry-cured salami in the context of this study. In particular the lower aw values due to longer curing were associated with lower Salmonella presence in traditional dry-cured salami.

      PubDate: 2017-10-08T06:18:06Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.016
      Issue No: Vol. 262 (2017)
       
  • Molecular characterization of diarrheagenic Escherichia coli isolated from
           vegetables in Argentina
    • Authors: Juliana González; Jimena S. Cadona; Marcelo Sanz; Ana V. Bustamante; A. Mariel Sanso
      Abstract: Publication date: 16 November 2017
      Source:International Journal of Food Microbiology, Volume 261
      Author(s): Juliana González, Jimena S. Cadona, Marcelo Sanz, Ana V. Bustamante, A. Mariel Sanso
      The aim of this study was to investigate the prevalence of diarrheagenic E. coli strains in vegetables from the humid Pampa region, Argentina, and to determine the occurrence of serotypes and virulence genes in the isolates. A total of 373 fresh vegetable samples obtained from 41 different geographical points were examined. E. coli was detected in 38.6% of the samples. Ten isolates could be obtained from 14 samples presumptively positive for diarrheagenic E. coli: 8 were identified as atypical Enteropathogenic E. coli (aEPEC) and 2 as Verocytotoxigenic E. coli (VTEC). Lettuce and beet were the vegetables most frequently contaminated with pathogenic E. coli. The isolates belonged to serotypes O1:H7, O28:H19, O39:H40, O86:H31, O132:H8, O139:H20, O178:H7 and O178:H19, some of which reportedly have caused human illness, and one isolate resulted non typeable. Taking into account the distribution of 16 nle genes, 7 profiles were detected. On the other hand, all tested isolates harbored the gene encoding for the adhesin HcpA. Other adhesion related genes were also identified: ecpA and elfA were detected in 90%, lpfA 0113 in 60%, and ehaA in 50% of the isolates meanwhile ihaA was only observed in O178:H19 isolate. This VTEC isolate harbored, also, Cdt-V toxin and megaplasmid encoding genes such as espP, subA and epeA and exhibited a strong cytotoxic effect. These data is the first molecular E. coli report that confirms the presence of E. coli pathotypes circulating among vegetables in Argentina. Genetic characterization showed that in addition to eae or vtx genes, isolates obtained from vegetables harbored genes encoding other toxins, adhesins, and components related to the type III secretion system that could contribute to their virulence. In conclusion, this research shows that vegetables in Argentina may be the source of VTEC and EPEC infections in the community and therefore, they should be considered as vehicles for transmission of these potentially pathogenic bacteria.

      PubDate: 2017-10-08T06:18:06Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.021
      Issue No: Vol. 261 (2017)
       
  • Occurrence and growth of Listeria monocytogenes in packaged raw milk
    • Authors: Hanna Castro; Marjo Ruusunen; Miia Lindström
      Pages: 1 - 10
      Abstract: Publication date: 16 November 2017
      Source:International Journal of Food Microbiology, Volume 261
      Author(s): Hanna Castro, Marjo Ruusunen, Miia Lindström
      The increased availability of packaged raw drinking milk necessitates the investigation of the occurrence and growth of Listeria monocytogenes in raw milk during distribution and storage. The occurrence of L. monocytogenes in 105 retailed raw milk bottles, 115 bulk tank milk samples, 23 in-line milk filter socks and in 50 environmental samples collected from an on-farm dairy establishment were investigated. Growth of inoculated low-level L. monocytogenes contamination was also investigated in two types of raw milk packaging, namely in 1-litre plastic bottles and 3-litre bag-in-boxes, both stored at three different storage temperatures of 6, 8 and 10°C. The occurrence of L. monocytogenes was higher (4.8%) in bottled raw milk stored until the use-by-date of the package compared to fresh bulk tank milk (1.7%). L. monocytogenes counts were ≤13CFU/ml in bottled raw milk and ≤1CFU/ml in bulk tank milk. L. monocytogenes was not detected in the packaging facility, but occurred very frequently (39%) in the milk filter socks. Subtyping of L. monocytogenes isolates using pulsed-field gel-electrophoresis revealed seven pulsotypes, of which two occurred in multiple samples. Targeted inoculum levels of 1–2CFU/ml yielded L. monocytogenes counts≥100CFU/ml within seven days of storage in 22% of the raw milk packages stored at 6°C, and in all of the raw milk packages stored at 8°C. The frequent occurrence of L. monocytogenes in raw milk and the ability of a low-level L. monocytogenes contamination to grow at refrigeration temperatures highlight the importance of consumer education regarding the appropriate raw milk storage and handling.

      PubDate: 2017-09-06T13:23:23Z
      DOI: 10.1016/j.ijfoodmicro.2017.08.017
      Issue No: Vol. 261 (2017)
       
  • Metagenetic analysis of the bacterial communities of edible insects from
           diverse production cycles at industrial rearing companies
    • Authors: D. Vandeweyer; S. Crauwels; B. Lievens; L. Van Campenhout
      Pages: 11 - 18
      Abstract: Publication date: 16 November 2017
      Source:International Journal of Food Microbiology, Volume 261
      Author(s): D. Vandeweyer, S. Crauwels, B. Lievens, L. Van Campenhout
      Despite the continuing development of new insect-derived food products, microbial research on edible insects and insect-based foods is still very limited. The goal of this study was to increase the knowledge on the microbial quality of edible insects by comparing the bacterial community composition of mealworms (Tenebrio molitor) and crickets (Acheta domesticus and Gryllodes sigillatus) from several production cycles and rearing companies. Remarkable differences in the bacterial community composition were found between different mealworm rearing companies and mealworm production cycles from the same company. In comparison with mealworms, the bacterial community composition of the investigated crickets was more similar among different companies, and was highly similar between both cricket species investigated. Mealworm communities were dominated by Spiroplasma and Erwinia species, while crickets were abundantly colonised by (Para)bacteroides species. With respect to food safety, only a few operational taxonomic units could be associated with potential human pathogens such as Cronobacter or spoilage bacteria such as Pseudomonas. In summary, our results implicate that at least for cricket rearing, production cycles of constant and good quality in terms of bacterial composition can be obtained by different rearing companies. For mealworms however, more variation in terms of microbial quality occurs between companies.

      PubDate: 2017-09-06T13:23:23Z
      DOI: 10.1016/j.ijfoodmicro.2017.08.018
      Issue No: Vol. 261 (2017)
       
  • Evaluation of chemical immersion treatments to reduce microbial
           populations in fresh beef
    • Authors: Ahmed Kassem; Joseph Meade; James Gibbons; Kevina McGill; Ciara Walsh; James Lyng; Paul Whyte
      Pages: 19 - 24
      Abstract: Publication date: 16 November 2017
      Source:International Journal of Food Microbiology, Volume 261
      Author(s): Ahmed Kassem, Joseph Meade, James Gibbons, Kevina McGill, Ciara Walsh, James Lyng, Paul Whyte
      The aim of the current study was to assess the ability of a number of chemicals (acetic Acid (AA), citric acid (CA) lactic acid (LA), sodium decanoate (SD) and trisodium phosphate (TSP)) to reduce microbial populations (total viable count, Campylobacter jejuni, Escherichia coli, Salmonella typhimurium and Listeria monocytogenes) on raw beef using an immersion system. The following concentrations of each chemical were used: 3 & 5% for AA, CA, LA, SD and 10 &12% for TSP. Possible synergistic effects of using combinations of two chemicals sequentially (LA+CA and LA+AA) were also investigated. L*, a* and b* values were measured before and after treatments and ΔE* values were calculated in order to determine any changes in the color of meat due to the use of these chemicals. In general, all chemical treatments resulted in significantly (p <0.05) reduced bacterial counts when compared to untreated controls. The greatest reductions were obtained by using LA3%, SD5%, AA5%, LA5% and SD3% for TVC, C. jejuni, E. coli, S. typhimurium and L. monocytogenes, respectively. However, no significant difference in microbial load was observed between the different concentrations of each chemical used (p >0.05). The application of combinations of chemical immersion treatments (LA3%+AA3% and LA3%+CA3%) did not result in further significant reductions in microbial populations when compared to single chemical treatments (P <0.05). Assessment of color changes in meat following the application of chemical immersion treatments indicated that using AA or CA at either concentration and LA at 5% led to an increase in the ΔE* value of >3 immediately after treatment and after 24h storage. The remaining treatments did not result in significant changes to the color of raw beef.

      PubDate: 2017-09-11T13:31:00Z
      DOI: 10.1016/j.ijfoodmicro.2017.08.005
      Issue No: Vol. 261 (2017)
       
  • Cells-qPCR as a direct quantitative PCR method to avoid microbial DNA
           extractions in grape musts and wines
    • Authors: Verónica Soares-Santos; Isabel Pardo; Sergi Ferrer
      Pages: 25 - 34
      Abstract: Publication date: 16 November 2017
      Source:International Journal of Food Microbiology, Volume 261
      Author(s): Verónica Soares-Santos, Isabel Pardo, Sergi Ferrer
      A novel quantitative PCR assay called Cells-qPCR has been developed for the rapid detection and quantification of yeasts, lactic acid bacteria (LAB) and acetic acid bacteria (AAB) directly from grape must and wine that does not require DNA extraction. The assay was tested on Brettanomyces bruxellensis, Saccharomyces cerevisiae, Lactobacillus plantarum, Oenococcus oeni, Acetobacter aceti and Gluconobacter oxydans in culture media, and in white and red grape musts and wines. Standard curves were constructed from DNA and cells for the six target species in all the matrices. Good efficiencies were obtained for both when comparing DNA and cells standard curves. No reaction inhibition was observed between matrices for each species. Cells quantification was linear over a range of cell concentrations (7, 5 or 4 orders of magnitude) and detected as few as one cell per reaction in all the matrices. The developed Cells-qPCR assay is a robust, reliable, fast and specific method to detect and quantify different yeasts, LAB and AAB species in grape must and wine that avoids DNA extraction and overcomes the presence of inhibitors like polyphenols and ethanol.

      PubDate: 2017-09-11T13:31:00Z
      DOI: 10.1016/j.ijfoodmicro.2017.08.019
      Issue No: Vol. 261 (2017)
       
  • Passion fruit by-product and fructooligosaccharides stimulate the growth
           and folate production by starter and probiotic cultures in fermented
           soymilk
    • Authors: Marcela Albuquerque Cavalcanti Albuquerque; Raquel Bedani; Jean Guy LeBlanc; Susana Marta Isay Saad
      Pages: 35 - 41
      Abstract: Publication date: 16 November 2017
      Source:International Journal of Food Microbiology, Volume 261
      Author(s): Marcela Albuquerque Cavalcanti Albuquerque, Raquel Bedani, Jean Guy LeBlanc, Susana Marta Isay Saad
      Two starter cultures (Streptococcus (St.) thermophilus ST-M6 and TA-40) and five probiotic strains (St. thermophilus TH-4, Lactobacillus (Lb.) acidophilus LA-5, Lb. rhamnosus LGG, Lb. fermentum PCC, and Lb. reuteri RC-14) were used to ferment different soymilk formulations supplemented with passion fruit by-product and/or fructo-oligosaccharides (FOS) with the aim of increasing folate concentrations. Growth and folate production of individual strains were evaluated and the results used to select co-cultures. Both St. thermophilus ST-M6 and TH-4 were the best folate producers and were able to increase the folate content of all soymilk formulations when used alone or in co-culture with lactobacilli strains, especially in the presence of both passion fruit by-product and FOS. Thus, passion fruit by-product and FOS could be used as dietary ingredients to stimulate the folate production by selected bacterial strains during the fermentation of soymilk. It was also shown that vitamin production by microorganisms is strain-dependent and may also be influenced by nutritional and environmental conditions.

      PubDate: 2017-09-11T13:31:00Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.001
      Issue No: Vol. 261 (2017)
       
  • Colorimetric aptasensor for the detection of Salmonella enterica serovar
           typhimurium using ZnFe2O4-reduced graphene oxide nanostructures as an
           effective peroxidase mimetics
    • Authors: Shijia Wu; Nuo Duan; Yueting Qiu; Jinghong Li; Zhouping Wang
      Pages: 42 - 48
      Abstract: Publication date: 16 November 2017
      Source:International Journal of Food Microbiology, Volume 261
      Author(s): Shijia Wu, Nuo Duan, Yueting Qiu, Jinghong Li, Zhouping Wang
      A new colorimetric aptasensor platform was fabricated to detect Salmonella enterica serovar typhimurium based on the peroxidase-like activity of ZnFe2O4-reduced graphene oxide (ZnFe2O4/rGO) nanostructures. The synthesized ZnFe2O4/rGO can catalytically oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) by H2O2 and generate a typical blue product, which was detected by micro-reader at 652nm. Therefore, ZnFe2O4/rGO was conjugated with aptamer to act as the signal probe. Biotin modified aptamer was immobilized onto the micro-plate to act as the capture probe. In the presence of target, a “sandwich-type” complex of aptamer (on micro-plate)-target-aptamer-ZnFe2O4/rGO complexes was formed through specific recognition of aptamers and corresponding target. The limit of detection was 11cfu/mL and the detection range was 11 to 1.10×105 cfu/mL of S. typhimurium in buffer solution. Actual samples analysis indicated that this colorimetric aptasensor produced results consistent with plate-counting analysis. The developed method was simple and sensitive, which may pave the way for the detection of other pathogenic bacteria with suitable aptamers.

      PubDate: 2017-09-18T02:28:15Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.002
      Issue No: Vol. 261 (2017)
       
  • Production of the Sicilian distillate “Spiritu re fascitrari” from
           honey by-products: An interesting source of yeast diversity
    • Authors: Raimondo Gaglio; Antonio Alfonzo; Nicola Francesca; Onofrio Corona; Rosalia Di Gerlando; Pietro Columba; Giancarlo Moschetti
      Pages: 62 - 72
      Abstract: Publication date: 16 November 2017
      Source:International Journal of Food Microbiology, Volume 261
      Author(s): Raimondo Gaglio, Antonio Alfonzo, Nicola Francesca, Onofrio Corona, Rosalia Di Gerlando, Pietro Columba, Giancarlo Moschetti
      The “Spiritu re fascitrari” (SRF) is a typical Sicilian distillate obtained from the by-products of traditional process of honey production. Although some alcoholic fermentation of honey based products have been described, the present research represents the first investigation on the yeast ecology and the physico-chemical characteristics of honey by-products subjected to an alcoholic fermentation followed by distillation. All samples collected during manufacturing process were analysed for the count of total, osmophilic and osmotolerant yeasts. The honeycombs and equipment surfaces showed the presence of yeasts that was 1.7 and 1.1 Log (CFU/mL), respectively. After enrichment, yeast populations increased and a significant increase of yeasts was registered during the alcoholic fermentation (AF), reaching loads higher than 7LogCFU/mL after day 6. A total of 2816 colonies of yeasts were isolated from the count plates and the following species were genetically identified: Lachancea fermentati, Pichia anomala, Pichia kudriavzevii, Saccharomyces cerevisiae, Wickerhamomyces anomalus, Zygosaccharomyces bailii and Zygosaccharomyces rouxii. During the spontaneous AF process, the species S. cerevisiae, Z. bailii and Z. rouxii were mainly isolated and the feed conversion ratio of sugars into ethanol was about 53%; high contents of acetic acid and glycerol were also found. The highest concentrations of volatile organic compounds (VOCs) were registered for esters, alcohols and aldehydes (346.55, 331.041 and 13.65μg/L, respectively). Many VOCs identified as “specific floral markers” such as nonanal and 1-hexanol, 1-octanal and linalool oxide were found. Although more studies are needed, our results suggested that the S. cerevisiae strains isolated in this study must be evaluated in situ for their potential to act as starters for the continuous production of SRF. This because these strains are expected to drive the fermentation process reducing the risk of off-odour and off-flavour formation.

      PubDate: 2017-10-14T06:24:12Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.004
      Issue No: Vol. 261 (2017)
       
  • Application of next generation sequencing toward sensitive detection of
           enteric viruses isolated from celery samples as an example of produce
    • Authors: Zhihui Yang; Mark Mammel; Efstathia Papafragkou; Kaoru Hida; Christopher A. Elkins; Michael Kulka
      Pages: 73 - 81
      Abstract: Publication date: 16 November 2017
      Source:International Journal of Food Microbiology, Volume 261
      Author(s): Zhihui Yang, Mark Mammel, Efstathia Papafragkou, Kaoru Hida, Christopher A. Elkins, Michael Kulka
      Next generation sequencing (NGS) holds promise as a single application for both detection and sequence identification of foodborne viruses; however, technical challenges remain due to anticipated low quantities of virus in contaminated food. In this study, with a focus on data analysis using several bioinformatics tools, we applied NGS toward amplification-independent detection and identification of norovirus at low copy (<103 copies) or within multiple strains from produce. Celery samples were inoculated with human norovirus (stool suspension) either as a single norovirus strain, a mixture of strains (GII.4 and GII.6), or a mixture of different species (hepatitis A virus and norovirus). Viral RNA isolation and recovery was confirmed by RT-qPCR, and optimized for library generation and sequencing without amplification using the Illumina MiSeq platform. Extracts containing either a single virus or a two-virus mixture were analyzed using two different analytic approaches to achieve virus detection and identification. First an overall assessment of viral genome coverage for samples varying in copy numbers (1.1×103 to 1.7×107) and genomic content (single or multiple strains in various ratios) was completed by reference-guided mapping. Not unexpectedly, this targeted approach to identification was successful in correctly mapping reads, thus identifying each virus contained in the inoculums even at low copy (estimated at 12 copies). For the second (metagenomic) approach, samples were treated as “unknowns” for data analyses using (i) a sequence-based alignment with a local database, (ii) an “in-house” k-mer tool, (iii) a commercially available metagenomics bioinformatic analysis platform cosmosID, and (iv) an open-source program Kraken. Of the four metagenomics tools applied in this study, only the local database alignment and in-house k-mer tool were successful in detecting norovirus (as well as HAV) at low copy (down to <103 copies) and within a mixture of virus strains or species. The results of this investigation provide support for continued investigation into the development and integration of these analytical tools for identification and detection of foodborne viruses.

      PubDate: 2017-10-14T06:24:12Z
      DOI: 10.1016/j.ijfoodmicro.2017.07.021
      Issue No: Vol. 261 (2017)
       
  • Persistence and reduction of Shiga toxin-producing Escherichia coli
           serotype O26:H11 in different types of raw fermented sausages
    • Authors: Christina Böhnlein; Jan Kabisch; Stefanie Müller-Herbst; Gregor Fiedler; Charles M.A.P. Franz; Rohtraud Pichner
      Pages: 82 - 88
      Abstract: Publication date: 16 November 2017
      Source:International Journal of Food Microbiology, Volume 261
      Author(s): Christina Böhnlein, Jan Kabisch, Stefanie Müller-Herbst, Gregor Fiedler, Charles M.A.P. Franz, Rohtraud Pichner
      Fermented sausages have been identified as source of several outbreaks of Shiga toxin-producing Escherichia coli (STEC). Illnesses linked to non-O157 STEC serotypes appear to be on the rise worldwide, and serogroup O26 is the second most reported in Europe after O157. However, data on the behavior of serogroup O26 in food are rare, so that the aim of this study was to investigate the survival of STEC O26:H11 in different types of fermented sausages (“Teewurst”, fast-ripened and long-fermented salami). Challenge studies were performed with an inoculation cocktail which consisted of three STEC O26:H11 strains isolated from human, cattle and food sources. In the short-ripened spreadable sausage type “Teewurst” STEC counts decreased by only 0.5 log10 within 28days. In contrast, STEC reductions from 2.2 to 2.6 log10 units were observed in the different salami products, while the most pronounced decrease of 1.0 log10 unit within one day was detected in fast-ripened sausages with glucono delta-lactone (GdL). Moreover, numbers of the food-associated E. coli O26:H11 strain were significantly higher (p <0.001) than those of the human and cattle STEC O26:H11 strains in all types of fermented sausages. Approximately 60% of all STEC isolates from GdL salami shared the genotypic virulence profile of the food-associated E. coli O26:H11 strain. In summary, hurdles of acidification and drying during salami ripening resulted in reductions of STEC O26:H11 counts. However, our results also indicate that STEC O26:H11 can persist in the environment of “Teewurst” and might therefore pose a risk to public health.

      PubDate: 2017-10-14T06:24:12Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.019
      Issue No: Vol. 261 (2017)
       
  • Antimicrobial evaluation of novel poly-lactic acid based nanocomposites
           incorporated with bioactive compounds in-vitro and in refrigerated
           vacuum-packed cooked sausages
    • Authors: Mohammadreza Rezaeigolestani; Ali Misaghi; Ali Khanjari; Afshin Akhondzadeh Basti; Ali Abdulkhani; Samira Fayazfar
      Pages: 1 - 10
      Abstract: Publication date: 2 November 2017
      Source:International Journal of Food Microbiology, Volume 260
      Author(s): Mohammadreza Rezaeigolestani, Ali Misaghi, Ali Khanjari, Afshin Akhondzadeh Basti, Ali Abdulkhani, Samira Fayazfar
      Biodegradability and antimicrobial activity of food packaging materials are among the most attractive parameters in modern food industries. In order to develop biodegradable poly-lactic acid (PLA) film to antibacterial nanocomposites, different concentration of Zataria multiflora Bioss. essential oil (ZME), propolis ethanolic extract (PEE) and cellulose nanofiber (CNF) were incorporated to the polymer by solvent casting method. The resulting films were characterized by mechanical and physical tests and their antimicrobial application was evaluated in-vitro against four common foodborne pathogens and in vacuum-packed cooked sausages during refrigerated storage. Mechanical examination revealed that addition of ZME and PEE made films more flexible and incorporation of CNF improved almost all mechanical parameters tested. Moreover, according to physical analysis, incorporation of 0.5% v/v ZME to the composite primary solutions improved water vapor permeability of the resulting films. Almost all of the active films were effective against the tested bacteria except for PLA/PEE films, and maximum antibacterial effects recorded for the films containing both ZME and PEE. Based on the microbiological and sensory evaluation of the sausages, all of the PLA/1%ZME/PEE composites increased the shelf life to >40days. The results indicate that incorporation of natural antimicrobial substances such as ZME and PEE to packaging material could be an interesting approach in development of active packaging material without significant negative effect on polymer technical properties.

      PubDate: 2017-09-06T13:23:23Z
      DOI: 10.1016/j.ijfoodmicro.2017.08.006
      Issue No: Vol. 260 (2017)
       
  • Biofilm of Escherichia coli O157:H7 on cantaloupe surface is resistant to
           lauroyl arginate ethyl and sodium hypochlorite
    • Authors: Yezhi Fu; Amanda J. Deering; Arun K. Bhunia; Yuan Yao
      Pages: 11 - 16
      Abstract: Publication date: 2 November 2017
      Source:International Journal of Food Microbiology, Volume 260
      Author(s): Yezhi Fu, Amanda J. Deering, Arun K. Bhunia, Yuan Yao
      Biofilms formed by Escherichia coli O157:H7 on cantaloupe rind were characterized in this study. Cantaloupe rind pieces inoculated with E. coli O157:H7 B6-914 was sampled after 2, 12, and 24h incubation for imaging with cryo-scanning electron microscopy (Cryo-SEM) or treating with lauroyl arginate ethyl (LAE) or sodium hypochlorite (SHC). Cryo-SEM images showed that E. coli O157:H7 formed a biofilm within 12h on the rind surface. For rind samples treated with LAE or SHC, the residual cell counts were significantly different (p <0.05) between 2 and 12h incubation, and between 2 and 24h of incubation. For the 2h incubation samples, E. coli O157:H7 was undetectable (>5-log reduction) after treatment with 2000μg/mL of LAE or SHC. In contrast, for 12h incubation samples, 2000μg/mL of LAE or SHC could only achieve 1.74 or 1.86-log reduction, respectively. The study showed the low efficacy of LAE and SHC on cantaloupe rind surface to reduce the E. coli biofilm, suggesting the needs for cantaloupe cleaning methods beyond washing with conventional antimicrobial agents.

      PubDate: 2017-09-06T13:23:23Z
      DOI: 10.1016/j.ijfoodmicro.2017.08.008
      Issue No: Vol. 260 (2017)
       
  • Evaluation of pulsed light treatments on inactivation of Salmonella on
           blueberries and its impact on shelf-life and quality attributes
    • Authors: Xinang Cao; Runze Huang; Haiqiang Chen
      Pages: 17 - 26
      Abstract: Publication date: 2 November 2017
      Source:International Journal of Food Microbiology, Volume 260
      Author(s): Xinang Cao, Runze Huang, Haiqiang Chen
      Blueberry have a short shelf life when fully ripe and susceptible to contamination of various pathogens. Our study investigated the effect of pulsed light (PL) on inactivation of Salmonella on blueberries and its impact on shelf-life, quality attributes and health-benefit compounds of blueberries. Dry PL (6J/cm2) and water-assisted PL (samples were agitated in water during PL treatment; 9J/cm2) along with two controls, dry control (untreated) and water-assisted control (water washing without PL), were applied to blueberries with subsequent storages at room temperature (3days) or 5°C (7days). For Salmonella inactivation, dry PL treatment achieved 0.9 and 0.6 log reduction of Salmonella for spot and dip inoculation, respectively; while the water-assisted PL treatment reduced Salmonella by 4.4 log and 0.8 log for spot and dip inoculation, respectively. The water-assisted PL treatment resulted in Salmonella populations significantly lower than the dry control after storage regardless of the storage temperature and inoculation method. Neither dry nor water-assisted PL treatments improved the shelf life of blueberries even though direct inactivation of natural yeasts and molds were achieved. Surface lightness was instantly reduced after both dry and water-assisted PL treatments. Compared with the dry control, the two PL treatments did not reduce the firmness of blueberries. Weight loss was increased for the dry PL treated samples, but not for the water-assisted PL treatment for both storage conditions. Delayed anthocyanins accumulation and reduced total antioxidant activity were induced by both PL treatments at the end of storage at room temperature, while slight enhancement in total phenolics content was achieved by water-assisted PL treatment. In conclusion, the water-assisted PL treatment could effectively decontaminate Salmonella on blueberries while showed minimal or no impact on the shelf-life, quality attributes and health-benefit compounds of blueberries. PL processing parameters need to be further evaluated and optimized before possible application in the blueberry industry.

      PubDate: 2017-09-06T13:23:23Z
      DOI: 10.1016/j.ijfoodmicro.2017.08.012
      Issue No: Vol. 260 (2017)
       
  • Exploring the microbial origins of p-cresol and its co-occurrence pattern
           in the Chinese liquor-making process
    • Authors: Hai Du; Bo Liu; Xueshan Wang; Yan Xu
      Pages: 27 - 35
      Abstract: Publication date: 2 November 2017
      Source:International Journal of Food Microbiology, Volume 260
      Author(s): Hai Du, Bo Liu, Xueshan Wang, Yan Xu
      The compound p-cresol is the major off-odor and toxic component of strong aroma-type Chinese liquor. To trace its origin, the p-cresol contents in the liquor-making process were detected by gas chromatography-mass spectrometry. The prokaryotic communities involved in the process were revealed by 16S rRNA gene MiSeq sequencing. The results showed that the microbial diversity and concentration of p-cresol in pit mud significantly increased with increased pit depth. Canonical correspondence analysis further revealed that p-cresol was positively correlated with the genera Aminobacterium, Clostridium, Sedimentibacter and Syntrophomonas. On investigating potential p-cresol producers, we obtained 11 species from pit mud samples using selective culture media. Clostridium butyricum, Clostridium tyrobutyricum, Clostridium aminovalericum and Eubacterium contortum were confirmed to possess the capacity for p-cresol production. Moreover, based on volatile compounds data, these strains were assigned to the same clusters characterized by the high abundance of butanoic acid and p-cresol. Furthermore, 24 pairs of significant correlations were identified from 14 genera using co-occurrence network analysis. Clostridium was the hub in pit mud and could be inhibited by increasing levels of Lactobacillus. These findings represented a step forward for controlling p-cresol in a complex microbial community of Chinese liquor.

      PubDate: 2017-09-06T13:23:23Z
      DOI: 10.1016/j.ijfoodmicro.2017.08.016
      Issue No: Vol. 260 (2017)
       
  • Lactobionic acid enhances the synergistic effect of nisin and thymol
           against Listeria monocytogenes Scott A in tryptic soy broth and milk
    • Authors: Huaiqiong Chen; Qixin Zhong
      Pages: 36 - 41
      Abstract: Publication date: 2 November 2017
      Source:International Journal of Food Microbiology, Volume 260
      Author(s): Huaiqiong Chen, Qixin Zhong
      Listeria monocytogenes is a Gram-positive opportunistic human pathogen and it remains a significant cause of foodborne illnesses. A variety of natural and synthetic compounds have been studied to inhibit the growth of L. monocytogenes in foods. Antimicrobial combinations with synergistic antilisterial properties can reduce the dose of each antimicrobial, which can be further enhanced by chelating compounds. Therefore, the objective of this study was to determine antilisterial properties of binary or ternary combinations of lactobionic acid (LBA), nisin, and thymol in tryptic soy broth (TSB), 2% reduced-fat milk, and whole milk. The results showed that the minimum inhibitory concentration (MIC) of nisin, thymol and LBA was 125IU/mL, 0.25mg/mL, and 10mg/mL, respectively. The ternary combination was the most effective in reducing MICs of antimicrobials, with the MIC of nisin, thymol, and LBA being 31.25IU/mL, 0.0625mg/mL, and 1.25mg/mL, respectively. In TSB with 0.6% yeast extract, L. monocytogenes grew in individual or binary antimicrobial treatments of 31.25IU/mL nisin, 0.0625mg/mL thymol, and 1.25mg/mL LBA within 24h at 32°C, while it was completely inhibited by the ternary combination. In 2% reduced-fat milk at 21°C, the ternary combination of nisin, thymol, and LBA at respective concentrations of 250IU/mL, 2mg/mL, and 10mg/mL completely inhibited the bacterium to below the detection limit in 72h while >2log (CFU/mL) bacteria was still detected in all the binary combinations after 120h. In whole milk, the combination of 500IU/mL nisin, 2mg/mL thymol, and 10mg/mL LBA reduced bacteria to around 2log (CFU/mL) in 4h at 21°C, and no bacterial recovery was observed after 5 d. This study suggested the potential of the ternary combination of nisin, thymol and LBA for food preservation.

      PubDate: 2017-09-06T13:23:23Z
      DOI: 10.1016/j.ijfoodmicro.2017.08.013
      Issue No: Vol. 260 (2017)
       
  • Antimicrobial efficacy of Cinnamomum javanicum plant extract against
           Listeria monocytogenes and its application potential with smoked salmon
    • Authors: Wenqian Yuan; Hui Wen Lee; Hyun-Gyun Yuk
      Pages: 42 - 50
      Abstract: Publication date: 2 November 2017
      Source:International Journal of Food Microbiology, Volume 260
      Author(s): Wenqian Yuan, Hui Wen Lee, Hyun-Gyun Yuk
      Extracts from medicinal plants have been reported to possess good antimicrobial properties, but a majority of them remain unexplored. This study aimed at identifying a novel plant extract with antimicrobial activity, to validate its efficacy in food model, and to elucidate its composition and antimicrobial mechanism. A total of 125 plant extracts were screened, and Cinnamomum javanicum leaf and stem extract showed potential antimicrobial activity against Listeria monocytogenes (MIC=0.13mg/mL). Total phenolic content of the extract was 78.3mg GAE/g extract and its antioxidant activity was 57.2–326.5mg TE/g extract. When applied on cold smoked salmon, strong strain-dependent antimicrobial effectiveness was observed, with L. monocytogenes LM2 (serotype 4b) and LM8 (serotype 3a) being more resistant compared to SSA81 (serotype 1/2a). High extract concentration (16mg/mL) was needed to inhibit or reduce the growth of L. monocytogenes on smoked salmon, which resulted in surface color change. GC-MS revealed that eucalyptol (25.54 area%) was the most abundant compound in the crude extract. Both crude extract and eucalyptol induced significant membrane damages in treated L. monocytogenes. These results suggest anti-L. monocytogenes activity of C. javanicum plant extract, identified its major volatile components, and elucidated its membrane-damaging antimicrobial mechanisms.

      PubDate: 2017-09-06T13:23:23Z
      DOI: 10.1016/j.ijfoodmicro.2017.08.015
      Issue No: Vol. 260 (2017)
       
  • Impact of the reusing of food manufacturing wastewater for irrigation in a
           closed system on the microbiological quality of the food crops
    • Authors: Luciano Beneduce; Giuseppe Gatta; Antonio Bevilacqua; Angela Libutti; Emanuele Tarantino; Micol Bellucci; Eleonora Troiano; Giuseppe Spano
      Pages: 51 - 58
      Abstract: Publication date: 2 November 2017
      Source:International Journal of Food Microbiology, Volume 260
      Author(s): Luciano Beneduce, Giuseppe Gatta, Antonio Bevilacqua, Angela Libutti, Emanuele Tarantino, Micol Bellucci, Eleonora Troiano, Giuseppe Spano
      In order to evaluate if the reuse of food industry treated wastewater is compatible for irrigation of food crops, without increased health risk, in the present study a cropping system, in which ground water and treated wastewater were used for irrigation of tomato and broccoli, during consecutive crop seasons was monitored. Water, crop environment and final products were monitored for microbial indicators and pathogenic bacteria, by conventional and molecular methods. The microbial quality of the irrigation waters influenced sporadically the presence of microbial indicators in soil. No water sample was found positive for pathogenic bacteria, independently from the source. Salmonella spp. and Listeria monocytogenes were detected in soil samples, independently from the irrigation water source. No pathogen was found to contaminate tomato plants, while Listeria monocytogenes and E. coli O157:H7 were detected on broccoli plant, but when final produce were harvested, no pathogen was detected on edible part. The level of microbial indicators and detection of pathogenic bacteria in field and plant was not dependent upon wastewater used. Our results, suggest that reuse of food industry wastewater for irrigation of agricultural crop can be applied without significant increase of potential health risk related to microbial quality.

      PubDate: 2017-09-06T13:23:23Z
      DOI: 10.1016/j.ijfoodmicro.2017.08.009
      Issue No: Vol. 260 (2017)
       
  • Combination of essential oil compounds and phenolic acids against
           
    • Authors: Natan V.B. Meira; Richard A. Holley; Keliani Bordin; Renata E.F. de Macedo; Fernando B. Luciano
      Pages: 59 - 64
      Abstract: Publication date: 2 November 2017
      Source:International Journal of Food Microbiology, Volume 260
      Author(s): Natan V.B. Meira, Richard A. Holley, Keliani Bordin, Renata E.F. de Macedo, Fernando B. Luciano
      Escherichia coli O157:H7 is a foodborne pathogen that causes hemorrhagic colitis and hemolytic uremic syndrome. The low dose of infection and severity of the disease represent a concern to public health. Natural compounds have been widely applied as food additives to replace synthetic preservatives. The aim of this study was to determine the efficiency of essential oil compounds (EOCs) in combination with phenolic acids (PA) in vitro and in dry-fermented sausage production. Minimum Inhibitory Concentration (MIC) and Fractional Inhibitory Concentration index (FICindex) were determined for a 5-strain mixture of E. coli O157:H7. Batches of sausage tainted with E. coli O157:H7 were produced using Pediococcus pentosaceus UM 116P and Staphylococcus carnosus UM 123M as starter cultures. The best combination of EOCs and PAs found in vitro was used as an additive. Chemical–physical and microbiological analyses were evaluated weekly from day 0 to 35 after production. Sensory evaluation (texture, odor, flavor, appearance and overall evaluation) of E. coli-free sausages was conducted using a 9-point hedonic scale with 56 untrained volunteers. The MIC values of allyl isothiocyanate (AITC), carvacrol (CAR), ferulic acid (FA), o-coumaric acid (CA) and p-hydroxybenzoic acid (AHB) were, respectively, 0.25; 1.3; 5.12; 18.27; and 37mM. AITC combined with CA had a synergistic effect (FICindex =0.25) and together they were applied in the production of dry fermented sausage at concentrations of 10× FIC and 20× FIC. Aw had no significant difference among treatments, whereas the pH of 10× FIC and 20× FIC were higher than the control. E. coli O157:H7 was reduced by >5logCFU/g with 20× FIC after 21d, and by 2.8logCFU/g with 10× FIC after 35d. Sensory analysis showed that the combination of AITC and ο-coumaric acid in both treatments presented lower scores in the 5 categories when compared to the control, but none of the parameters received a negative score. This study demonstrated that the combination of AITC and ο-coumaric acid at 20× FIC reduced E. coli O157:H7 in compliance with the North American legislation, but adjustments in the dose are necessary to improve the sensory characteristics of the final product.

      PubDate: 2017-09-06T13:23:23Z
      DOI: 10.1016/j.ijfoodmicro.2017.08.010
      Issue No: Vol. 260 (2017)
       
  • Effects of ultraviolet light emitting diodes (LEDs) on microbial and
           enzyme inactivation of apple juice
    • Authors: Merve Pelvan Akgün; Sevcan Ünlütürk
      Pages: 65 - 74
      Abstract: Publication date: 2 November 2017
      Source:International Journal of Food Microbiology, Volume 260
      Author(s): Merve Pelvan Akgün, Sevcan Ünlütürk
      In this study, the effects of Ultraviolet light-emitting diodes (UV-LEDs) on the inactivation of E. coli K12 (ATCC 25253), an indicator organism of E. coli O157:H7, and polyphneoloxidase (PPO) in cloudy apple juice (CAJ) were investigated. The clear (AJ) and cloudy apple juice were exposed to UV rays for 40min by using a UV device composed of four UV-LEDs with peak emissions at 254 and 280nm and coupled emissions as follows: 254/365, 254/405, 280/365, 280/405 and 254/280/365/405nm. UV-LEDs at 254nm achieved 1.6±0.1 log10 CFU/mL inactivation of E. coli K12 at UV dose of 707.2mJ/cm2. The highest inactivation of E. coli K12 (2.0±0.1log10 CFU/mL and 2.0±0.4log10 CFU/mL) was achieved when the cloudy apple juice was treated with both 280nm and 280/365nm UV-LEDs. For clear apple juice the highest inactivation 4.4log10 CFU/mL obtained for E. coli K12 was achieved using 4 lamps emitting light at 280nm for 40min exposure time. For the same treatment time, the experiments using a combination of lamps emitting light at 280 and 365nm (2lamp/2lamp) were resulted in 3.9±0.2log10 CFU/mL reductions. UV-A and UV-C rays in combination showed a better inactivation effect on PPO than UV-C rays used separately. Residual activity of PPO in CAJ was reduced to 32.58% when treated with UV-LED in combination of UV-C (280nm) and UV-A (365nm) rays. Additionally, the total color change (ΔE) of CAJ subjected to combined UV-LED irradiation at 280/365nm was the lowest compared to other studied processing conditions. This study provides key implications for the future application of UV-LEDs to fruit juice pasteurization.

      PubDate: 2017-09-11T13:31:00Z
      DOI: 10.1016/j.ijfoodmicro.2017.08.007
      Issue No: Vol. 260 (2017)
       
  • Decontamination of fresh-cut cucumber slices by a combination of a
           modified chitosan coating containing carvacrol nanoemulsions and pulsed
           light
    • Authors: Özge Taştan; Gianpiero Pataro; Francesco Donsì; Giovanna Ferrari; Taner Baysal
      Pages: 75 - 80
      Abstract: Publication date: 2 November 2017
      Source:International Journal of Food Microbiology, Volume 260
      Author(s): Özge Taştan, Gianpiero Pataro, Francesco Donsì, Giovanna Ferrari, Taner Baysal
      In this study, the impact of the combination of pulsed light (PL) treatments with antimicrobial coatings, consisting of modified chitosan suspensions incorporating carvacrol nanoemulsions, was investigated on the decontamination of fresh-cut cucumber slices. The upper surface of the cucumber slices, with or without the coating deposition, was inoculated with Escherichia coli ATCC 26 to reach a final concentration of 107 CFU/g of the vegetable. PL treatments were conducted at different fluence (4, 8, and 12J/cm2) on the inoculated surface of cucumber slices. Results showed that the microbial reduction was only marginally affected by the coating formulation. A slight increase was observed when the carvacrol nanoemulsions were embedded in the chitosan matrix, but microbial reduction levels remained always below 1log cycle. In contrast, the different PL treatments resulted in a statistically significant increase in inactivation with increasing the treatment fluence, reaching 2.6log cycles at the maximum fluence. Remarkably, the combination of the antimicrobial coating with the most intense PL treatments resulted in a strong synergistic effect. For example, by combining a PL treatment at 12J/cm2 with one of the antimicrobial coatings a microbial reduction >5log cycles was reached. Therefore, it can be concluded that the combination of antimicrobial coatings and PL treatment is a promising method for surface decontamination of fresh-cut vegetables, which could be exploited in view of ensuring their microbiological safety.

      PubDate: 2017-09-11T13:31:00Z
      DOI: 10.1016/j.ijfoodmicro.2017.08.011
      Issue No: Vol. 260 (2017)
       
  • Plant-mediated restriction of Salmonella enterica on tomato and spinach
           leaves colonized with Pseudomonas plant growth-promoting rhizobacteria
    • Authors: Chiun-Kang Hsu; Shirley A. Micallef
      Pages: 1 - 6
      Abstract: Publication date: 16 October 2017
      Source:International Journal of Food Microbiology, Volume 259
      Author(s): Chiun-Kang Hsu, Shirley A. Micallef
      Reducing Salmonella enterica association with plants during crop production could reduce risks of fresh produce-borne salmonellosis. Plant growth-promoting rhizobacteria (PGPR) colonizing plant roots are capable of promoting plant growth and boosting resistance to disease, but the effects of PGPR on human pathogen-plant associations are not known. Two root-colonizing Pseudomonas strains S2 and S4 were investigated in spinach, lettuce and tomato for their plant growth-promoting properties and their influence on leaf populations of S. enterica serovar Newport. Plant roots were inoculated with Pseudomonas in the seedling stage. At four (tomato) and six (spinach and lettuce) weeks post-germination, plant growth promotion was assessed by shoot dry weight (SDW) and leaf chlorophyll content measurements. Leaf populations of S. Newport were measured after 24h of leaf inoculation with this pathogen by direct plate counts on Tryptic Soy Agar. Root inoculation of spinach cv. ‘Tyee’, with Pseudomonas strain S2 or S4 resulted in a 69% and 63% increase in SDW compared to non-inoculated controls (p <0.005 and p <0.01, respectively). Similarly, Romaine lettuce cv. ‘Parris Island Cos’ responded positively to S2 and S4 inoculation (53% and 48% SDW increase, respectively; p <0.05), and an increase in leaf chlorophyll content (p <0.001), compared to controls. Tomato cv. ‘Nyagous’ yielded significantly greater SDW (74%, p <0.01 and 54%, p <0.05 for S2 and S4, respectively), and also higher leaf chlorophyll content (19% and 29%, p <0.001, respectively) relative to controls. Leaf chlorophyll content only increased in S4-inoculated tomato cv. ‘Moneymaker’ plants (27%, p <0.001), although both S2 and S4 promoted plant growth by over 40% compared to controls (p <0.01 and p <0.05, respectively). No significant growth promotion was detected in tomato cv. ‘BHN602’, but S2-inoculated plants had elevated leaf chlorophyll content (13%, p <0.01). Root inoculation with Pseudomonas S4 restricted S. Newport populations inoculated on leaves of spinach (p <0.001) and all three tomato cultivars (p <0.05), compared to controls, 24h post Salmonella inoculation. Impairment of S. Newport leaf populations was also observed on spinach when plant roots were inoculated with S2 (p <0.01). With an initial leaf inoculum of approximately 6.0logCFU of S. Newport/plant, the significantly greater reduction of S. Newport populations on Pseudomonas-treated plants than those on non-inoculated control plants after 24h was modest with differences of one log or less. By contrast, the survival of S. Newport on the leaves of Romaine lettuce was not influenced by Pseudomonas root colonization. These findings provide evidence that root inoculation of certain specialty crops with beneficial Pseudomonas strains exhibiting PGPR properties may not only promote plant growth, but also reduce the fitness of epiphytic S. enterica in the phyllosphere. Plant-mediated effects induced by PGPR may be an effective strategy to minimize contamination of crops with S. enterica during cultivation.

      PubDate: 2017-08-07T08:35:02Z
      DOI: 10.1016/j.ijfoodmicro.2017.07.012
      Issue No: Vol. 259 (2017)
       
  • Inside Front Cover - Editorial Board
    • Abstract: Publication date: 4 December 2017
      Source:International Journal of Food Microbiology, Volume 262


      PubDate: 2017-10-14T06:24:12Z
       
  • ICFMH Announcment
    • Abstract: Publication date: 4 December 2017
      Source:International Journal of Food Microbiology, Volume 262


      PubDate: 2017-10-14T06:24:12Z
       
  • Bacteria, mould and yeast spore inactivation studies by scanning electron
           microscope observations
    • Authors: Siti N.M. Rozali; Elham A. Milani; Rebecca C. Deed; Filipa V.M. Silva
      Abstract: Publication date: Available online 4 October 2017
      Source:International Journal of Food Microbiology
      Author(s): Siti N.M. Rozali, Elham A. Milani, Rebecca C. Deed, Filipa V.M. Silva
      Spores are the most resistant form of microbial cells, thus difficult to inactivate. The pathogenic or food spoilage effects of certain spore-forming microorganisms have been the primary basis of sterilization and pasteurization processes. Thermal sterilization is the most common method to inactivate spores present on medical equipment and foods. High pressure processing (HPP) is an emerging and commercial non-thermal food pasteurization technique. Although previous studies demonstrated the effectiveness of thermal and non-thermal spore inactivation, the in-depth mechanisms of spore inactivation are as yet unclear. Live and dead forms of two food spoilage bacteria, a mould and a yeast were examined using scanning electron microscopy before and after the inactivation treatment. Alicyclobacillus acidoterrestris and Geobacillus stearothermophilus bacteria are indicators of acidic foods pasteurization and sterilization processes, respectively. Neosartorya fischeri is a phyto-pathogenic mould attacking fruits. Saccharomyces cerevisiae is a yeast with various applications for winemaking, brewing, baking and the production of biofuel from crops (e.g. sugar cane). Spores of the four microbial species were thermally inactivated. Spores of S. cerevisiae were observed in the ascus and free form after thermal and HPP treatments. Different forms of damage and cell destruction were observed for each microbial spore. Thermal treatment inactivated bacterial spores of A. acidoterrestris and G. stearothermophilus by attacking the inner core of the spore. The heat first altered the membrane permeability allowing the release of intracellular components. Subsequently, hydration of spores, physicochemical modifications of proteins, flattening and formation of indentations occurred, with subsequent spore death. Regarding N. fischeri, thermal inactivation caused cell destruction and leakage of intracellular components. Both thermal and HPP treatments of S. cerevisiae free spores attacked the inner membrane, altering its permeability, and allowing in final stages the transfer of intracellular components to the outside. The spore destruction caused by thermal treatment was more severe than HPP, as HPP had less effect on the spore core. All injured spores have undergone irreversible volume and shape changes. While some of the leakage of spore contents is visible around the deformed but fully shaped spore, other spores exhibited large indentations and were completely deformed, apparently without any contents inside. This current study contributed to the understanding of spore inactivation by thermal and non-thermal processes.

      PubDate: 2017-10-08T06:18:06Z
      DOI: 10.1016/j.ijfoodmicro.2017.10.008
       
  • New insights into resistance to colistin and third-generation
           cephalosporins of Escherichia coli in poultry, Portugal: Novel
           blaCTX-M-166 and blaESAC genes
    • Authors: Vera Manageiro; Lurdes Clemente Rafael Ivone Correia Teresa Albuquerque Ferreira
      Abstract: Publication date: Available online 4 October 2017
      Source:International Journal of Food Microbiology
      Author(s): Vera Manageiro, Lurdes Clemente, Rafael Graça, Ivone Correia, Teresa Albuquerque, Eugénia Ferreira, Manuela Caniça
      The increasing incidence of intestinal colonization with extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae and Gram negative organisms that has been observed in food animals such as poultry, cattle and pigs, are suggestive that animals, food and environment are potential sources of ESBL-producing bacteria. Hence, the aim of this study was to characterized commensal E. coli obtained from healthy broiler and turkey flocks at slaughter for the presence of penicillinases-, ESBL-, extended-spectrum AmpC (ESAC)-, plasmid-mediated quinolone resistance- and MCR-encoding genes. Study of clonal relatedness showed genetic diversity among CTX-M-type, SHV-12 and TEM-52 producing isolates with human isolates of the same type, was also assessed. We detected that eleven (5.4%, 11/202) and forty-five (2.2%, 45/185) E. coli isolates from broilers and turkeys, respectively, carried bla ESBL or bla ESAC genes and two isolates from turkeys carried mcr-1 gene. A new variant bla CTX-M-166 was reported in a multidrug resistant isolate from a broiler flock. Overall, we detected a diversity of resistance mechanisms among E. coli from food-producing animals, all of them with high importance at a public health level.

      PubDate: 2017-10-08T06:18:06Z
       
  • IPMP Global Fit – A one-step direct data analysis tool for
           predictive microbiology
    • Authors: Lihan Huang
      Abstract: Publication date: Available online 20 September 2017
      Source:International Journal of Food Microbiology
      Author(s): Lihan Huang
      The objective of this work is to develop and validate a unified optimization algorithm for performing one-step global regression analysis of isothermal growth and survival curves for determination of kinetic parameters in predictive microbiology. The algorithm is incorporated with user-friendly graphical interfaces (GUIs) to develop a data analysis tool, the USDA IPMP-Global Fit. The GUIs are designed to guide the users to easily navigate through the data analysis process and properly select the initial parameters for different combinations of mathematical models. The software is developed for one-step kinetic analysis to directly construct tertiary models by minimizing the global error between the experimental observations and mathematical models. The current version of the software is specifically designed for constructing tertiary models with time and temperature as the independent model parameters in the current package. The software is tested with a total of 9 different combinations of primary and secondary models for growth and survival of various microorganisms. The results of data analysis show that this software provides accurate estimates of kinetic parameters. In addition, it can be used to improve the experimental design and data collection for more accurate estimation of kinetic parameters. IPMP-Global Fit can be used in combination with the regular USDA-IPMP for solving the inverse problems and developing tertiary models in predictive microbiology.

      PubDate: 2017-09-24T02:18:52Z
      DOI: 10.1016/j.ijfoodmicro.2017.09.010
       
  • Inside Front Cover - Editorial Board
    • Abstract: Publication date: 2 November 2017
      Source:International Journal of Food Microbiology, Volume 260


      PubDate: 2017-09-11T13:31:00Z
       
  • ICFMH Announcment
    • Abstract: Publication date: 2 November 2017
      Source:International Journal of Food Microbiology, Volume 260


      PubDate: 2017-09-11T13:31:00Z
       
  • Inside Front Cover - Editorial Board
    • Abstract: Publication date: 16 October 2017
      Source:International Journal of Food Microbiology, Volume 259


      PubDate: 2017-09-06T13:23:23Z
       
 
 
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