Hannu Korkeala

Summary

Affiliation: University of Helsinki
Country: Finland

Publications

  1. doi request reprint Introducing scientific training into the veterinary curriculum of the University of Helsinki
    Hannu Korkeala
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, P O Box 66, 00014 University of Helsinki, Finland
    J Vet Med Educ 36:83-8. 2009
  2. ncbi request reprint Listeria monocytogenes contamination in pork can originate from farms
    Sanna Hellström
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland
    J Food Prot 73:641-8. 2010
  3. ncbi request reprint Reduction of enteropathogenic Yersinia in the pig slaughterhouse by using bagging of the rectum
    Riikka Laukkanen
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, P O Box 66, 00014 Helsinki University, Finland
    J Food Prot 73:2161-8. 2010
  4. doi request reprint Yersinia pekkanenii sp. nov
    Anna Murros-Kontiainen
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Finland
    Int J Syst Evol Microbiol 61:2363-7. 2011
  5. ncbi request reprint Pilot-scale continuous ultrasonic cleaning equipment reduces Listeria monocytogenes levels on conveyor belts
    Riina Tolvanen
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
    J Food Prot 72:408-11. 2009
  6. doi request reprint Variation in the prevalence of enteropathogenic Yersinia in slaughter pigs from Belgium, Italy, and Spain
    Pilar Ortiz Martínez
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
    Foodborne Pathog Dis 8:445-50. 2011
  7. ncbi request reprint Prevalence and diversity of Clostridium botulinum types A, B, E and F in honey produced in the Nordic countries
    Mari Nevas
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, P O Box 66, 00014 Helsinki, Finland
    Int J Food Microbiol 105:145-51. 2005
  8. doi request reprint Contamination of carcasses with human pathogenic Yersinia enterocolitica 4/O:3 originates from pigs infected on farms
    Riikka Laukkanen
    Department of Food and Environmental Hygiene, Helsinki University, Finland
    Foodborne Pathog Dis 6:681-8. 2009
  9. ncbi request reprint Prevalence and genetic diversity of Listeria monocytogenes in vacuum-packaged ready-to-eat meat products at retail markets in Latvia
    Aivars Berzins
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, P O Box 66, FI 00014 Helsinki, Finland
    J Food Prot 72:1283-7. 2009
  10. doi request reprint Prevalence of enteropathogenic Yersinia in Estonian, Latvian, and Russian (Leningrad region) pigs
    Pilar Ortiz Martínez
    Department of Food and Environmental Hygiene, University of Helsinki, Finland
    Foodborne Pathog Dis 6:719-24. 2009

Detail Information

Publications85

  1. doi request reprint Introducing scientific training into the veterinary curriculum of the University of Helsinki
    Hannu Korkeala
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, P O Box 66, 00014 University of Helsinki, Finland
    J Vet Med Educ 36:83-8. 2009
    ..It appears that organizing supervised research training within the veterinary curriculum increases veterinary students' interest in scientific work...
  2. ncbi request reprint Listeria monocytogenes contamination in pork can originate from farms
    Sanna Hellström
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland
    J Food Prot 73:641-8. 2010
    ..monocytogenes was present in the production chain, and transmission of the pathogen was possible throughout the chain, from the farm to pork. Good farm-level practices can therefore be utilized to reduce the prevalence of this pathogen...
  3. ncbi request reprint Reduction of enteropathogenic Yersinia in the pig slaughterhouse by using bagging of the rectum
    Riikka Laukkanen
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, P O Box 66, 00014 Helsinki University, Finland
    J Food Prot 73:2161-8. 2010
    ..Slaughterhouse environments can contaminate carcasses with enteropathogenic Yersinia, but the plausible main contamination source is the pig carrying the pathogen...
  4. doi request reprint Yersinia pekkanenii sp. nov
    Anna Murros-Kontiainen
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Finland
    Int J Syst Evol Microbiol 61:2363-7. 2011
    ..Based on the results of the phylogenetic and DNA-DNA hybridization analyses, a novel species, Yersinia pekkanenii sp. nov., is proposed. The type strain is ÅYV7.1KOH2(T) ( = DSM 22769(T)  = LMG 25369(T))...
  5. ncbi request reprint Pilot-scale continuous ultrasonic cleaning equipment reduces Listeria monocytogenes levels on conveyor belts
    Riina Tolvanen
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
    J Food Prot 72:408-11. 2009
    ..01). Ultrasonic cleaning for 10 s at 50 degrees C reduced L. monocytogenes counts by more than 5 log units. These results indicate that ultrasonic cleaning of a conveyor belt is effective even with short treatment times...
  6. doi request reprint Variation in the prevalence of enteropathogenic Yersinia in slaughter pigs from Belgium, Italy, and Spain
    Pilar Ortiz Martínez
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
    Foodborne Pathog Dis 8:445-50. 2011
    ..enterocolitica in Belgium, Italy, and Spain. Bioserotype 4/O:3 of Y. enterocolitica and bioserotypes 2/O:3 and 1/O:1 of Y. pseudotuberculosis have been shown to predominate...
  7. ncbi request reprint Prevalence and diversity of Clostridium botulinum types A, B, E and F in honey produced in the Nordic countries
    Mari Nevas
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, P O Box 66, 00014 Helsinki, Finland
    Int J Food Microbiol 105:145-51. 2005
    ..At a similarity level of 95%, four clusters were produced, three of which contained 20 of the 24 analysed strains. One of the clusters included isolates from both Denmark and Norway...
  8. doi request reprint Contamination of carcasses with human pathogenic Yersinia enterocolitica 4/O:3 originates from pigs infected on farms
    Riikka Laukkanen
    Department of Food and Environmental Hygiene, Helsinki University, Finland
    Foodborne Pathog Dis 6:681-8. 2009
    ..Specific farm factors, i.e. drinking from a nipple, absence of coarse feed or bedding for slaughter pigs, and no access of pest animals to pig house, were associated with a high prevalence of pathogenic Y. enterocolitica 4/O:3...
  9. ncbi request reprint Prevalence and genetic diversity of Listeria monocytogenes in vacuum-packaged ready-to-eat meat products at retail markets in Latvia
    Aivars Berzins
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, P O Box 66, FI 00014 Helsinki, Finland
    J Food Prot 72:1283-7. 2009
    ..monocytogenes contamination as a recurrent problem within one meat processing plant...
  10. doi request reprint Prevalence of enteropathogenic Yersinia in Estonian, Latvian, and Russian (Leningrad region) pigs
    Pilar Ortiz Martínez
    Department of Food and Environmental Hygiene, University of Helsinki, Finland
    Foodborne Pathog Dis 6:719-24. 2009
    ..Pigs seem to be an important reservoir of human enteropathogenic Y. enterocolitica 4/O:3 and Y. pseudotuberculosis 2/O:3 in these countries...
  11. ncbi request reprint PFGE genotyping and antimicrobial susceptibility of Campylobacter in retail poultry meat in Estonia
    Kristi Praakle-Amin
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, P O Box 66, FI 00014 University of Helsinki, Finland
    Int J Food Microbiol 114:105-12. 2007
    ..None of the chicken isolates were resistant to gentamicin, and no turkey isolates to erythromycin or gentamicin...
  12. pmc Comparative genomic hybridization analysis of two predominant Nordic group I (proteolytic) Clostridium botulinum type B clusters
    Miia Lindstrom
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, P O Box 66, 00014 Helsinki University, Finland
    Appl Environ Microbiol 75:2643-51. 2009
    ..botulinum type B clusters present a public health hazard in Nordic countries. Knowing the genetic and physiological markers of these clusters will assist in targeting control measures against these pathogens...
  13. ncbi request reprint Developing microbial spoilage population in vacuum-packaged charcoal-broiled European river lamprey (Lampetra fluviatilis)
    Lauri O Merivirta
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, P O Box 57, University of Helsinki, Helsinki FIN 00014, Finland
    Int J Food Microbiol 101:145-52. 2005
    ..halotolerans, have commonly been associated with spoilage of fishery products, but in these vacuum-packaged lampreys, they were not the dominant organisms within the developing spoilage population...
  14. ncbi request reprint Factors associated with Listeria monocytogenes contamination of cold-smoked pork products produced in Latvia and Lithuania
    Aivars Berzins
    Department of Food and Environmental Hygiene, University of Helsinki, P O Box 66, FIN 00014 Helsinki, Finland
    Int J Food Microbiol 115:173-9. 2007
    ..monocytogenes contamination existed over periods of time in several meat processing plants. In two meat processing plants, persistent L. monocytogenes strains belonging to serotypes 1/2a and 1/2c were found...
  15. doi request reprint Pathogenic Yersinia enterocolitica 2/O:9 and Yersinia pseudotuberculosis 1/O:1 strains isolated from human and non-human sources in the Plateau State of Nigeria
    Ameh E J Okwori
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland
    Food Microbiol 26:872-5. 2009
    ..The dominating genotype of Y. enterocolitica 2/O:9 strains among humans was also found among strains isolated from pig, fermented cow milk and traditional intestine pepper soap samples...
  16. pmc Alternative sigma factor σE has an important role in stress tolerance of Yersinia pseudotuberculosis IP32953
    Eveliina Palonen
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
    Appl Environ Microbiol 79:5970-7. 2013
    ..The results were confirmed with complementation of the mutant. Thus, σ(E) plays a significant role in the stress tolerance of Y. pseudotuberculosis IP32953 and probably contributes to the survival of this pathogen in the food chain. ..
  17. pmc Comparative genomic hybridization analysis shows different epidemiology of chromosomal and plasmid-borne cpe-carrying Clostridium perfringens type A
    Päivi Lahti
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
    PLoS ONE 7:e46162. 2012
    ..Thus the epidemiology of the food poisonings caused by two populations appears different, the plasmid-borne cpe-positive strains probably contaminating foods via humans and the chromosomal strains being connected to plant material...
  18. ncbi request reprint Hazard and control of group II (non-proteolytic) Clostridium botulinum in modern food processing
    Miia Lindstrom
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, P O Box 66, 00014 University of Helsinki, Finland
    Int J Food Microbiol 108:92-104. 2006
    ..This sets great challenges on the production of chilled packaged foods. To ensure the safety of these foods, more than one factor should safeguard against botulinal growth and toxin production...
  19. ncbi request reprint Proteolytic Clostridium botulinum type B in the gastric content of a patient with type E botulism due to whitefish eggs
    Miia Lindstrom
    Department of Food and Environmental Hygiene, University of Helsinki, Finland
    Foodborne Pathog Dis 1:53-7. 2004
    ..This is the first domestic case of foodborne botulism in Finland...
  20. ncbi request reprint Ultrasonic cleaning of conveyor belt materials using Listeria monocytogenes as a model organism
    Riina Tolvanen
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland
    J Food Prot 70:758-61. 2007
    ..The logarithmic reduction was significantly higher (P = 0.013) in cleaning treatments with potassium hydroxide detergent. In this study, ultrasonic cleaning was efficient for cleaning conveyor belt materials...
  21. doi request reprint Novel insights into the epidemiology of Clostridium perfringens type A food poisoning
    Miia Lindstrom
    Department of Food Hygiene and Environmental Health, Centre of Excellence in Microbial Food Safety Research, Faculty of Veterinary Medicine, P O Box 66, 00014 University of Helsinki, Finland
    Food Microbiol 28:192-8. 2011
    ..perfringens food poisoning fail to detect and isolate many C. perfringens strains, distorting the epidemiological understanding of C. perfringens food poisoning...
  22. ncbi request reprint The detection and prevalence of Clostridium botulinum in pig intestinal samples
    Jan Myllykoski
    Department of Food and Environmental Hygiene, P O Box 66, 00014 University of Helsinki, Finland
    Int J Food Microbiol 110:172-7. 2006
    ..C. botulinum was isolated from two PCR-positive samples and confirmed to be type B by PCR. Both isolates were shown to be proteolytic and thus to represent C. botulinum group I...
  23. doi request reprint Clostridium botulinum in cattle and dairy products
    Miia Lindstrom
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland
    Crit Rev Food Sci Nutr 50:281-304. 2010
    ....
  24. ncbi request reprint Group I Clostridium botulinum strains show significant variation in growth at low and high temperatures
    Katja Hinderink
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, P O Box 66, 00014 Helsinki, Finland
    J Food Prot 72:375-83. 2009
    ..The significant variation between strains of group I C. botulinum may have an impact on inoculation studies and predictive modeling when assessing the safety of foods...
  25. ncbi request reprint Survival of Listeria monocytogenes strains in a dry sausage model
    Riina Tolvanen
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, P O Box 66, FIN 00014 University of Helsinki, Finland
    J Food Prot 71:1550-5. 2008
    ..Protective cultures such as L. plantarum may be used as part of a hurdle strategy in dry sausage processing, but variations in susceptibility of different L. monocytogenes strains can create problems if other hurdles are not included...
  26. ncbi request reprint Low prevalence of yadA-positive Yersinia enterocolitica in sows
    Tiina Korte
    Department of Food and Environmental Hygiene, University of Helsinki, Finland
    Foodborne Pathog Dis 1:45-52. 2004
    ..enterocolitica 4/O:3 strains persisting among slaughter swine were demonstrated to be very stable genetically. This study shows that fattening pigs are an important reservoir of different genotypes of Y. enterocolitica 4/O:3 strains...
  27. pmc Expression of signal transduction system encoding genes of Yersinia pseudotuberculosis IP32953 at 28°C and 3°C
    Eveliina Palonen
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
    PLoS ONE 6:e25063. 2011
    ..05) lower at 3°C than at 28°C. The results suggest that several signal transduction systems might be used during growth at low temperature, and at least, CheA/CheY two-component system is important for low-temperature growth...
  28. doi request reprint Clostridium tyrobutyricum strains show wide variation in growth at different NaCl, pH, and temperature conditions
    Marjo Ruusunen
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, P O Box 66, 00014 University of Helsinki, Finland
    J Food Prot 75:1791-5. 2012
    ..Understanding the physiological diversity among the strains is important when designing food control measures and predictive models for the growth of spoilage organisms in cheese...
  29. doi request reprint Yersinia nurmii sp. nov
    Anna Murros-Kontiainen
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Finland
    Int J Syst Evol Microbiol 61:2368-72. 2011
    ..Based on phylogenetic, phenotypic and DNA-DNA reassociation data, a novel species, Yersinia nurmii sp. nov., is proposed for the isolated strains. The type strain is APN3a-c(T) ( = DSM 22296(T)  = LMG 25213(T))...
  30. pmc Transmission of Yersinia pseudotuberculosis in the pork production chain from farm to slaughterhouse
    Riikka Laukkanen
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, P O Box 66, Fi 00014 Helsinki University, Finland
    Appl Environ Microbiol 74:5444-50. 2008
    ..On farms, contact with pest animals and the outside environment and a rise in the number of pigs on the farm appear to increase the prevalence of Y. pseudotuberculosis...
  31. ncbi request reprint An 8-year surveillance of the diversity and persistence of Listeria monocytogenes in a chilled food processing plant analyzed by amplified fragment length polymorphism
    Riikka Keto-Timonen
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, P O Box 66, FI 00014 University of Helsinki, Finland
    J Food Prot 70:1866-73. 2007
    ..In compartment II, reconstruction of the production line resulted in reduced prevalence rates of L. monocytogenes and elimination of two persistent AFLP types...
  32. ncbi request reprint Meat inspection education in Finnish veterinary curriculum
    Janne Lunden
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland
    J Vet Med Educ 34:205-11. 2007
    ..This article outlines the subjects to be included in the modern, high-quality meat-inspection curriculum recommended by the expert panel...
  33. ncbi request reprint Contamination routes of Clostridium botulinum in the honey production environment
    Mari Nevas
    Department of Food and Environmental Hygiene, PO Box 66, 00014 University of Helsinki, Helsinki, Finland
    Environ Microbiol 8:1085-94. 2006
    ..botulinum spores in honey could possibly be diminished by increasing hygienic level in honey production...
  34. pmc Diversity of proteolytic Clostridium botulinum strains, determined by a pulsed-field gel electrophoresis approach
    Mari Nevas
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, PO Box 66, 00014 Helsinki University, Finland
    Appl Environ Microbiol 71:1311-7. 2005
    ..botulinum types A and B. However, epidemiological conclusions based on PFGE data only should be made with discretion, since highly similar PFGE patterns were noticed, especially within the type B strains...
  35. doi request reprint Growth of group II Clostridium botulinum strains at extreme temperatures
    Yağmur Derman
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, P O Box 66 Agnes Sjöbergin katu 2, 00014 University of Helsinki, Helsinki, Finland
    J Food Prot 74:1797-804. 2011
    ..The growth characteristics of group II C. botulinum and some type E strains with mesophilic growth properties may have an impact on inoculation studies and predictive modeling for assessing the safety of foods...
  36. pmc Laboratory diagnostics of botulism
    Miia Lindstrom
    Department of Food and Environmental Hygiene, University of Helsinki, P O Box 66, 00014 University of Helsinki, Finland
    Clin Microbiol Rev 19:298-314. 2006
    ..Therefore, the toxin-producing organisms should be routinely isolated from the patient and the vehicle. The physiological group and genetic traits of the isolates should be determined...
  37. ncbi request reprint Prevalence and genetic characterization of Listeria monocytogenes in retail broiler meat in Estonia
    Kristi Praakle-Amin
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland
    J Food Prot 69:436-40. 2006
    ..Seventy-one L. monocytogenes isolates, including all PFGE types, were serotyped, and three serotypes (1/2a, 1/2b, and 4b) were obtained. Serotype 1/2a accounted for 96% of the isolates...
  38. ncbi request reprint Raw and processed fish show identical Listeria monocytogenes genotypes with pulsed-field gel electrophoresis
    Annukka Markkula
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, P O Box 66, FI 00014, University of Helsinki, Helsinki, Finland
    J Food Prot 68:1228-31. 2005
    ..Some L. monocytogenes strains entering a plant may thus contaminate and persist in the processing environment, causing recurrent contamination of the final products via processing machines...
  39. pmc Piglets are a source of pathogenic Yersinia enterocolitica on fattening-pig farms
    Sonja Virtanen
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
    Appl Environ Microbiol 78:3000-3. 2012
    ..A few piglets were found to be already infected on breeding farms. After the piglets were mixed, the infection spread through the whole unit. Eventually, all the pigs excreted the pathogen...
  40. doi request reprint Wide variety of bioserotypes of enteropathogenic Yersinia in tonsils of English pigs at slaughter
    Pilar Ortiz Martínez
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, P O Box 66, Fi 00014 Helsinki University, Finland
    Int J Food Microbiol 139:64-9. 2010
    ..The high prevalence of Y. enterocolitica bioserotypes 2/O:9 and 2/O:5 found in this study suggests that English pigs are an important reservoir of these bioserotypes whereas in other European countries bioserotype 4/O:3 predominates...
  41. doi request reprint PCR assay for differentiating between Group I (proteolytic) and Group II (nonproteolytic) strains of Clostridium botulinum
    Elias Dahlsten
    Department of Food and Environmental Hygiene, University of Helsinki, Helsinki, Finland
    Int J Food Microbiol 124:108-11. 2008
    ..botulinum is an essential step in investigation of human botulism outbreaks, and should be considered as a diagnostic corner-stone in order to improve our epidemiological understanding of human botulism...
  42. ncbi request reprint Characterisation of persistent and sporadic Listeria monocytogenes strains by pulsed-field gel electrophoresis (PFGE) and amplified fragment length polymorphism (AFLP)
    Tiina Autio
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland
    Syst Appl Microbiol 26:539-45. 2003
    ..These results indicate that even though persistent strains differ from sporadic strains there seems not to be any specific evolutional lineage of persistent strains...
  43. ncbi request reprint Efficacy of disinfectants to reduce Listeria monocytogenes on precut iceberg lettuce
    Sanna Hellström
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland
    J Food Prot 69:1565-70. 2006
    ..Thus, strain-specific differences exist in the ability of L. monocytogenes to survive the washing treatments of the lettuce...
  44. doi request reprint Listeria monocytogenes serotypes 1/2c and 3c possess inlH
    Annukka Markkula
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
    Foodborne Pathog Dis 8:1125-9. 2011
    ..These results suggest that inlH is specifically present in serotype 1/2c, 3c, and a small fraction of 1/2a L. monocytogenes strains and exists as a single allele...
  45. pmc Plasmid-borne type E neurotoxin gene clusters in Clostridium botulinum strains
    Zhen Zhang
    Department of Food Hygiene and Environmental Health, Centre of Excellence in Microbial Food Safety Research, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
    Appl Environ Microbiol 79:3856-9. 2013
    ..Three strains were found to contain neurotoxin subtype E1 gene clusters in large plasmids of about 146 kb in size...
  46. doi request reprint Inhibition of toxigenesis of group II (nonproteolytic) Clostridium botulinum type B in meat products by using a reduced level of nitrite
    Riikka Keto-Timonen
    Department of Food Hygiene and Environmental Health, P O Box 66, FI 00014 University of Helsinki, Helsinki, Finland
    J Food Prot 75:1346-9. 2012
    ..The results suggest that the safety of processed meat products with respect to group II C. botulinum type B can be maintained even with a reduced concentration (75 mg/kg) of sodium nitrite...
  47. pmc Requirement for RNA helicase CsdA for growth of Yersinia pseudotuberculosis IP32953 at low temperatures
    Eveliina Palonen
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
    Appl Environ Microbiol 78:1298-301. 2012
    ..The role of CsdA in Y. pseudotuberculosis under cold conditions was confirmed by impaired growth of insertional csdA mutants at 3°C. The results suggest that CsdA is crucial for Y. pseudotuberculosis survival in the chilled food chain...
  48. pmc Identification of Clostridium species and DNA fingerprinting of Clostridium perfringens by amplified fragment length polymorphism analysis
    Riikka Keto-Timonen
    Department of Food and Environmental Hygiene, P O Box 66, FI 00014 University of Helsinki, Finland
    J Clin Microbiol 44:4057-65. 2006
    ..These results indicate that the AFLP method provides a promising tool for the identification and characterization of Clostridium species...
  49. pmc Infant botulism acquired from household dust presenting as sudden infant death syndrome
    Mari Nevas
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, P O Box 66, 00014 Helsinki University, Finland
    J Clin Microbiol 43:511-3. 2005
    ....
  50. pmc Two-component signal transduction system CBO0787/CBO0786 represses transcription from botulinum neurotoxin promoters in Clostridium botulinum ATCC 3502
    Zhen Zhang
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
    PLoS Pathog 9:e1003252. 2013
    ..This is the first evidence of a negative regulator controlling botulinum neurotoxin production. Understanding the neurotoxin regulatory mechanisms is a major target of the food and pharmaceutical industries alike...
  51. pmc Roles of four putative DEAD-box RNA helicase genes in growth of Listeria monocytogenes EGD-e under heat, pH, osmotic, ethanol, and oxidative stress conditions
    Annukka Markkula
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
    Appl Environ Microbiol 78:6875-82. 2012
    ..This study shows that the putative DEAD-box RNA helicase genes lmo0866 and lmo1450 play important roles in tolerance of L. monocytogenes EGD-e to ethanol, heat, alkali, and oxidative stresses...
  52. doi request reprint Genes encoding putative DEAD-box RNA helicases in Listeria monocytogenes EGD-e are needed for growth and motility at 3°C
    Annukka Markkula
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, PO Box 66, FI 00014 University of Helsinki, Finland
    Environ Microbiol 14:2223-32. 2012
    ..This study shows that the putative DEAD-box RNA helicase genes lmo0866, lmo1450 and lmo1722 are necessary for cold tolerance and motility of L. monocytogenes EGD-e...
  53. pmc Quantitative real-time reverse transcription-PCR analysis reveals stable and prolonged neurotoxin cluster gene activity in a Clostridium botulinum type E strain at refrigeration temperature
    Ying Chen
    Centre of Excellence in Microbial Food Safety Research, Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland
    Appl Environ Microbiol 74:6132-7. 2008
    ..In light of group II C. botulinum type E being a dangerous food-borne pathogen, these findings may be important in terms of the safety of refrigerated packaged foods of extended durability...
  54. pmc Elimination of botulinum neurotoxin (BoNT) type B from drinking water by small-scale (personal-use) water purification devices and detection of BoNT in water samples
    Ari Hörman
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland
    Appl Environ Microbiol 71:1941-5. 2005
    ..3 log10 units). The rapid EIAs intended for the detection of BoNT from various types of samples failed to detect BoNT from aqueous samples containing an estimated concentration of BoNT of 396,000 ng/liter...
  55. pmc The cold-induced two-component system CBO0366/CBO0365 regulates metabolic pathways with novel roles in group I Clostridium botulinum ATCC 3502 cold tolerance
    Elias Dahlsten
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
    Appl Environ Microbiol 80:306-19. 2014
    ..The results provide insight to the mechanisms group I C. botulinum utilizes in coping with cold. ..
  56. doi request reprint Role of flhA and motA in growth of Listeria monocytogenes at low temperatures
    Mirjami Mattila
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
    Int J Food Microbiol 148:177-83. 2011
    ..The results suggest that flhA and motA play a role in the cold tolerance of L. monocytogenes strain EGD-e, and that motile flagella may be needed for optimal cold stress response of L. monocytogenes...
  57. pmc Sequencing the botulinum neurotoxin gene and related genes in Clostridium botulinum type E strains reveals orfx3 and a novel type E neurotoxin subtype
    Ying Chen
    Department of Food and Environmental Hygiene, P O Box 66, FIN 00014, University of Helsinki, Finland
    J Bacteriol 189:8643-50. 2007
    ..The amino acid sequence of the subtype E6 neurotoxin differed 3 to 6% from the other subtypes, suggesting that these subtype E6 neurotoxins may possess specific antigenic or functional properties...
  58. pmc Clostridium perfringens type A strains carrying a plasmid-borne enterotoxin gene (genotype IS1151-cpe or IS1470-like-cpe) as a common cause of food poisoning
    Päivi Lahti
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, P O Box 66, FI 00014 University of Helsinki, Helsinki, Finland
    J Clin Microbiol 46:371-3. 2008
    ..These results show that C. perfringens type A carrying the plasmid-borne cpe is a common cause of food poisoning...
  59. pmc Low occurrence of pathogenic Yersinia enterocolitica in clinical, food, and environmental samples: a methodological problem
    Maria Fredriksson-Ahomaa
    Department of Food and Environmental Hygiene, University of Helsinki, Helsinki, Finland
    Clin Microbiol Rev 16:220-9. 2003
    ..enterocolitica in natural samples is clearly higher with PCR than with culture methods. The methods available for detection of pathogenic Y. enterocolitica in natural samples are reviewed in this article...
  60. ncbi request reprint Occurrence of Yersinia pseudotuberculosis in iceberg lettuce and environment
    Taina Niskanen
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland
    Adv Exp Med Biol 529:383-5. 2003
  61. ncbi request reprint Prevalence and characterisation of yadA-positive Yersinia enterocolitica in pig tonsils in 1995 and 1999
    Tiina Korte
    Department of Food and Environmental Hygiene, University of Helsinki, Finland
    Adv Exp Med Biol 529:367-9. 2003
  62. pmc The CLO3403/CLO3404 two-component system of Clostridium botulinum E1 Beluga is important for cold shock response and growth at low temperatures
    Gerald Mascher
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
    Appl Environ Microbiol 80:399-407. 2014
    ..The results suggest that the CLO3403/CLO3404 TCS is important for the cold tolerance of C. botulinum E1 Beluga. ..
  63. doi request reprint Sequencing of virulence genes shows limited genetic variability in Yersinia pseudotuberculosis
    Eveliina Palonen
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
    Foodborne Pathog Dis 10:21-7. 2013
    ..Sequencing of inv, virF, and yadA of 18 Y. pseudotuberculosis strains showed limited variability of inv and virF, whereas the sequences of yadA varied considerably...
  64. pmc Involvement of Clostridium botulinum ATCC 3502 sigma factor K in early-stage sporulation
    David G Kirk
    Department of Food Hygiene and Environmental Health, Centre of Excellence in Microbial Food Safety Research, Faculty of Veterinary Medicine, University of Helsinki, Finland
    Appl Environ Microbiol 78:4590-6. 2012
    ..subtilis. Understanding the sporulation mechanism of C. botulinum provides keys to control the public health risks that the spores of this dangerous pathogen cause through foods...
  65. ncbi request reprint Enterococcus species dominating in fresh modified-atmosphere-packaged, marinated broiler legs are overgrown by Carnobacterium and Lactobacillus species during storage at 6 degrees C
    Johanna Björkroth
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, P O Box 57, FIN 00014 Helsinki, Finland
    Int J Food Microbiol 97:267-76. 2005
    ..In general, when the initial LAB population is compared to the spoilage LAB, a shift from homofermentative cocci towards carnobacteria, Lactobacillus sakei/curvatus and heterofermentative rods is seen in this marinated product...
  66. pmc Efficient DNA fingerprinting of Clostridium botulinum types A, B, E, and F by amplified fragment length polymorphism analysis
    Riikka Keto-Timonen
    Department of Food and Environmental Hygiene, PO Box 66, FI 00014 University of Helsinki, Helsinki, Finland
    Appl Environ Microbiol 71:1148-54. 2005
    ..botulinum group identification...
  67. doi request reprint Adaptation of enteropathogenic Yersinia to low growth temperature
    Eveliina Palonen
    Department of Food and Environmental Hygiene, University of Helsinki, Finland
    Crit Rev Microbiol 36:54-67. 2010
    ..Understanding low temperature adaptation of psychrotrophs would help to control these pathogens. This review demonstrates that more studies on cold tolerance mechanisms of psychrotrophs are needed...
  68. pmc Type C botulism due to toxic feed affecting 52,000 farmed foxes and minks in Finland
    Miia Lindstrom
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland
    J Clin Microbiol 42:4718-25. 2004
    ..6 or below according to the manufacturer, it seems unlikely that spore germination and toxin formation occurred during overnight storage. Hence, the events leading to toxin formation were not determined...
  69. ncbi request reprint Adaptive and cross-adaptive responses of persistent and non-persistent Listeria monocytogenes strains to disinfectants
    Janne Lunden
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, P O Box 57, FIN 00014, Helsinki, Finland
    Int J Food Microbiol 82:265-72. 2003
    ..These findings suggest that sustaining high disinfectant effectiveness may be unsuccessful by rotation, even when using agents with different mechanisms of action...
  70. pmc virF-positive Yersinia pseudotuberculosis and Yersinia enterocolitica found in migratory birds in Sweden
    Taina Niskanen
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, FIN 00014 University of Helsinki, Finland
    Appl Environ Microbiol 69:4670-5. 2003
    ....
  71. ncbi request reprint Identification of lactic acid bacteria from spoiled, vacuum-packaged 'gravad' rainbow trout using ribotyping
    Ulrike Lyhs
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland
    Int J Food Microbiol 72:147-53. 2002
    ..Only one isolate was identified as C. divergens. Most of the carnobacteria were found in the samples stored at 3 degrees C. The relative proportion of L. sakei was higher in the samples stored at 8 degrees C...
  72. ncbi request reprint Leuconostoc gasicomitatum is the dominating lactic acid bacterium in retail modified-atmosphere-packaged marinated broiler meat strips on sell-by-day
    Tuija Susiluoto
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland
    Int J Food Microbiol 80:89-97. 2003
    ..curvatus subsp. curvatus (20 isolates) species. SLA proved not to be completely selective for lactobacilli because the growth of Leuconostoc spp. was not inhibited, Carnobacterium spp. were the only species not detected on SLA...
  73. ncbi request reprint Similar Listeria monocytogenes pulsotypes detected in several foods originating from different sources
    Tiina Autio
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland
    Int J Food Microbiol 77:83-90. 2002
    ..The existence of similar L. monocytogenes strains in various food products of several producers should be considered if food strain fingerprint results are used to help trace the vehicles for infections...
  74. pmc Important role of class I heat shock genes hrcA and dnaK in the heat shock response and the response to pH and NaCl stress of group I Clostridium botulinum strain ATCC 3502
    Katja Selby
    Department of Food Hygiene and Environmental Health, Agnes Sjöberginkatu 2, 00014 Helsinki University, Finland
    Appl Environ Microbiol 77:2823-30. 2011
    ..botulinum under the stressful environmental conditions that may be encountered during food processing or growth in food products, in the mammalian intestine, or in wounds...
  75. ncbi request reprint Yersinia pseudotuberculosis with limited genetic diversity is a common finding in tonsils of fattening pigs
    Taina Niskanen
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland
    J Food Prot 65:540-5. 2002
    ..Three pigs were found to carry more than one genotype. Overall, variations between PFGE patterns were small, indicating genetic homogeneity among pig strains of bioserotype 2/0:3...
  76. ncbi request reprint High prevalence of Clostridium botulinum types A and B in honey samples detected by polymerase chain reaction
    Mari Nevas
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland
    Int J Food Microbiol 72:45-52. 2002
    ..Strains of C. botulinum type A were isolated from 14 and type B from 2 of the 20 PCR-positive samples. This is the first report of type A spores of C. botulinum being detected and isolated in Fennoscandia...
  77. pmc Humans as reservoir for enterotoxin gene--carrying Clostridium perfringens type A
    Annamari Heikinheimo
    University of Helsinki, Helsinki, Finland
    Emerg Infect Dis 12:1724-9. 2006
    ..The results also indicate that humans should be considered a risk factor for spread of C. perfringens type A food poisoning and that they are a possible source of contamination for C. perfringens type A food poisoning...
  78. ncbi request reprint Yersinia pseudotuberculosis in pigs and pig houses in Finland
    Riikka Laukkanen
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
    Adv Exp Med Biol 529:371-3. 2003
  79. ncbi request reprint Contamination patterns of Listeria monocytogenes in cold-smoked pork processing
    Aivars Berzins
    Department of Food Hygiene and Environmental Health, University of Helsinki, PHelsinki, Finland
    J Food Prot 73:2103-9. 2010
    ..monocytogenes strains in the plant. Due to poor hygiene design, removal of the brining machine from the production of cold-smoked meat products should be considered to reduce L. monocytogenes contamination in the finished products...
  80. pmc Enumeration and isolation of cpe-positive Clostridium perfringens spores from feces
    Annamari Heikinheimo
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, P O Box 66, FIN 00014 Helsinki University, Finland
    J Clin Microbiol 42:3992-7. 2004
    ..perfringens. The method also offers a new approach in the investigation of the epidemiology of cpe-positive C. perfringens strains...
  81. ncbi request reprint Antibacterial efficiency of Finnish spice essential oils against pathogenic and spoilage bacteria
    Mari Nevas
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, 00014 University of Helsinki, Finland
    J Food Prot 67:199-202. 2004
    ..By gas chromatography-mass spectrometry analysis, differences were noted in the composition of oregano and thyme oils in comparison to previous reports...
  82. doi request reprint Phenotypic and transcriptomic analyses of Sigma L-dependent characteristics in Listeria monocytogenes EGD-e
    Mirjami Mattila
    Department of Food Hygiene and Environmental Health, University of Helsinki, Finland
    Food Microbiol 32:152-64. 2012
    ..monocytogenes EGD-e. These promote execution of various cellular processes and stress adaptation responses thereby enabling this bacterium to overcome various food preservation measures as well as antibiotics and other toxic chemicals...
  83. ncbi request reprint Prevalence and genetic diversity of Listeria monocytogenes in the tonsils of pigs
    Tiina Autio
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, P O Box 57, FIN 00014 Helsinki University, Finland
    J Food Prot 67:805-8. 2004
    ..The high prevalence of L. monocytogenes showing various PFGE types in the tonsils of pigs could indicate a potential source of contamination of pluck sets, carcasses, and the slaughterhouse environment and of subsequent processing steps...
  84. pmc Population structure of the Yersinia pseudotuberculosis complex according to multilocus sequence typing
    Riikka Laukkanen-Ninios
    Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, P O Box 66, FI 00014, University of Helsinki, Finland
    Environ Microbiol 13:3114-27. 2011
    ..pseudotuberculosis s.s. In contrast, Y. pseudotuberculosis s.s., the Korean group and Y. pestis can all cause disease in humans...
  85. pmc Thermal inactivation of nonproteolytic Clostridium botulinum type E spores in model fish media and in vacuum-packaged hot-smoked fish products
    Miia Lindstrom
    Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, PO Box 57, FIN 00014 Helsinki, Finland
    Appl Environ Microbiol 69:4029-36. 2003
    ..The sensory qualities of safely processed and more lightly processed whitefish were similar, while differences between the sensory qualities of safely processed and lightly processed rainbow trout were observed...