Human noroviruses (HuNoVs) are a leading cause of foodborne gastroenteritis worldwide and spread easily among humans via the faecal-oral route. A low infective dose, a high viral load in the vomit and faeces of infected persons, a lack of long-term immunity following previous infection, and a high environmental stability of the viruses all enhance the spreading of HuNoV in the population.

The aim of this doctoral thesis is to investigate the prevalence of HuNoVs on environmental surfaces and to observe and measure virus transfer during manual food preparation. A method for the detection of HuNoV is optimized and used in the laboratory and also in field studies, both in a resort and in food preparation premises. Finally, ultraviolet light irradiation (UV) is tested as a means to inactivate the HuNoVs from environmental surfaces.

HuNoV and its surrogate murine norovirus (MuNoV) were detected from environmental surfaces by swabbing, after which the viruses were eluted from the swabs and their genomes were extracted by a commercial kit. HuNoV and MuNoV genomes were detected using reverse transcription quantitative polymerase chain reaction (RT-QPCR) method using specific primers and probes. The effects of UV on the viruses were investigated both by viability assays (MuNoV) and by RT-QPCR (MuNoV and HuNoV). An enzymatic pre-PCR treatment was conducted before RT-QPCR detection to distinguish infective viruses from non-infective viruses.

Out of the four swab materials tested for swabbing HuNoV on surfaces, the recovery rates of the viruses were highest for swabs made of microfiber and polyester. When stored at 4⁰C, HuNoV persisted well in swabs, whereas at 22⁰C, viruses persisted better on swabs moistened by phosphate buffered saline (PBS, pH 7.2) than by glycine buffer pH 9.5.

HuNoV and MuNoV transferred easily from the hands to the gloves when gloving. The viruses were also repeatedly transferred to the first recipient surface (left hand, cucumber, and knife) during the sandwich preparation process. Virus-contaminated gloves were estimated to spread HuNoV to the food servings more efficiently than a single contaminated cucumber can during handling.

In a resort, where a gastroenteritis outbreak had taken place, HuNoV was detected in 10/36 swabs (27.8%) taken from environmental surfaces and further genotyped as a new variant, GII.4 Sydney_2012. In the field study that was conducted in three food-processing companies with no recently reported outbreaks of gastroenteritis, 5/90 swabs (5.6%) in 2010, 4/168 swabs (2.4%) in 2011, and 7/82 swabs (8.5%) in 2012 were found to be HuNoV GII-positive. The positives were detected in a production line and from the food handlers break room and restroom areas.

UV was observed as a potential inactivation method for HuNoV: a loss of infectivity and a 4 log10 reduction of HuNoV surrogate MuNoV were observed when the virus-containing surfaces were exposed to UV dose of 60 mJ/cm2 or higher. Methods based on genome detection seemed to overestimate HuNoV persistence even when samples were pre-treated before the RT-QPCR was conducted.

As seen in the studies included in the thesis, HuNoV is transmitted very easily from hands to food and environmental surfaces. Proper hand hygiene combined with effective measures to inactivate HuNoV from surfaces, such as UV, is needed to manage the transmission of the virus. Adequate monitoring of the environment for virus contamination in potential fountainheads of gastroenteritis outbreaks, such as in hospitals and restaurants serving RTE foods, could prevent or restrict HuNoV outbreaks.

DVM Maria Rönnqvist will defend her doctoral dissertation entitled “Noroviruses on surfaces: Detection, transfer and inactivation” in the Faculty of Veterinary Medicine, University of Helsinki, on Friday 24th October 2014 at 12. The public examination will take place at the Walter Hall, EE Building, Agnes Sjöbergin katu 2, Helsinki.

Docent Veli-Jukka Anttila, will serve as the opponent, and Professor Marja-Liisa Hänninen as the custos.

Textbook Meat Inspection and Control in the Slaughterhouse was published in August 2014. It is a up-to-date reference book, which responds the changing needs of meat inspection and control.

The book is targeted at international use, primarily for veterinary students and vocational post-graduate degree students, but the book is also suitable for other meat inspection and control experts. Food safety, infectious diseases of animals, and animal welfare meet at the slaughterhouses, and that the book dealt with in many ways.

The authors are international experts in the field. The book is edited by DVM Thimjos Ninios, DVM, PhD, Docent  Janne Lundén, Professor Hannu Korkeala and Professor Maria Fredriksson-Ahomaa.

The book presentation can be found in publisher’s page: http://eu.wiley.com/WileyCDA/WileyTitle/productCd-1118525868.html.

The Second International Meeting on Food Control Research” was held in Latvia, Riga on April, 9th-11th, 2014. The meeting discussed widely food control from the surveillance of food-borne diseases to the disclosure of food control inspections.

“Food control research is a central research area in environmental health control, which is gaining increasingly more visibility around the world. “Those who carry out food control appreciate that food control organizations and methods are exposed to research so that food control can be developed” tells Janne Lundén, who examines the efficiency of food control.

The meeting was attended by about 50 food control researchers from eleven different countries, including the United States, Ireland, the UK, Germany, Sweden, and Denmark.

Department of Food Hygiene and Environmental Health was strongly represented at the meeting, the meeting was attended by Professor Hannu Korkeala, University Lecturers Mari Nevas and Janne Lundén, as well as Doctoral Students Karoliina Kettunen, Jenni Luukkanen, Tiina Läikkö- Roto, and Satu Tähkäpää.

Department’s researchers presented the following lectures at the meeting:

• Introduction by Mari Nevas
• Food control methods by Janne Lundén
• Use of enforcement measures in the local food control units in Finland by Karoliina Kettunen
• Distribution of meat inspection tasks in the high-capasity slaughterhouses by Jenni Luukkanen
• Consistency in the inspection processes of food control officials as the disks by Tiina Läikkö-Roto
• Patterns of food frauds by Satu Tähkäpää.

The meeting was arranged by the Institute of Food Safety, Animal Health and Environment (BIOR) in collaboration with the Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Latvia University of Agriculture, Ministry of Agriculture of Latvia, Food and Veterinary Service.

The meeting was the second in order. The first meeting was held in Helsinki in 2008, and it was organized by the Department of Food Hygiene and Environmental Health. The next meeting will be held in Ireland 2017.

The homepage of the meeting: http://www.bior.gov.lv/en/left-menu/news/meeting-2014

DVM Sonja Virtanen will defend the doctoral dissertation entitled “Epidemiology of Yersinia enterocolitica on pig farms” in the Faculty of Veterinary Medicine, University of Helsinki, on 21st February 2014 at 12:00. The public examination will take place at the following address: Biokeskus 2, auditorium 1041, Viikinkaari 5.

Professor Mikael Skurnik, University of Helsinki, will serve as the opponent, and Professor Hannu Korkeala as the custos.

The dissertation is also available in electronic form through the http://urn.fi/URN:ISBN:978-952-10-9745-4.

The article “The CLO3403/CLO3404 Two-Component System of Clostridium botulinum E1 Beluga Is Important for Cold Shock Response and Growth at Low Temperatures” published by Mascher et al. was selected as spotlight in the current issue (January 2014, volume 80, issue 1) of Applied and Environmental Microbiology.

Applied and Environmental Microbiology highlighted the article as shown below:

“A Two-Component System Responsible for Cold Tolerance of Clostridium botulinum Type E

Type E botulism outbreaks are mainly associated with consumption of contaminated, minimally processed, anaerobically packaged fish products, for which thermal control is not sufficient to prevent outgrowth from Clostridium botulinum type E spores. Mascher et al. (p. 399–407) demonstrate a two-component system that is important for the cold-shock response in C. botulinum type E and its growth at low temperatures. Understanding the mechanisms behind the cold tolerance of this life-threatening pathogen may reveal novel insights into the prevention of botulism outbreaks and is thus important for the development of control measures.”
“Copyright © 2014, American Society for Microbiology. All Rights Reserved.”

C. botulinum type E is mainly found in cold regions of the world and highly prevalent in the Baltic Sea and Finnish freshwaters. The authors (Gerald Mascher, Yağmur Derman, David G. Kirk, Eveliina Palonen, Miia Lindström and Hannu Korkeala) were focusing on the cold tolerance of C. botulinum E1 Beluga which allows the organism to grow and produce the life-threatening botulinum neurotoxin at temperatures as low as 3°C. Constructing the first knock-out mutants of C. botulinum type E allowed them to study this organism in more detail and they could show the important role of the CLO3403/CLO3404 TCS in cold tolerance of C. botulinum type E. The group is now investigating the mechanisms regulated by the TCS.

The work was performed in the Finnish Centre of Excellence in Microbial Food Safety Research and supported by the Academy of Finland (grants 141140, 118602), the Finnish Graduate School on Applied Bioscience, the Finnish Foundation of Veterinary Research, the European Community’s Seventh Framework Program FP7/2007-2013 (grant 237942), and the Doctoral Program of the Faculty of Veterinary Medicine of the University of Helsinki.

Link to the article: http://aem.asm.org/content/80/1/1.full

Programme

The course contains lectures, demonstrations, laboratory practice, presentations and writing tasks. The preliminary programme can be seen on NOVA webpage.

Course fee and accommodation

For PhD students registered at any of the NOVA member institutions, NOVA PhD courses are free of charge and includes accommodation and meals. Travel costs are not covered by NOVA.

For PhD or MSc students registered at any of the BOVA member institutions, NOVA PhD courses are free of charge. For the non-PhD/MSc students at BOVA member institution and for other Baltic PhD/MSc students course fee is 200 €. Accommodation and meals are charged by the course organisation. Travel arrangements should be made and travel costs should be covered by the participants.

Read more about course fees.

Registration

Registration for the course by https://elomake.helsinki.fi/lomakkeet/47156/lomake.html. The deadline for the registration is February 17^th, 2014. Course attendance is limited to 25 participants.

Additional information

Course leader, Dr. Leena Maunula, leena.maunula@helsinki.fi.

DVM Elias Dahlsten will defend his doctoral dissertation entitled
“Genetic mechanisms of stress response and sporulation in Clostridium botulinum” in the Faculty of Veterinary Medicine, University of Helsinki, on Friday 20th December 2013 at 12. The public examination will take place at the EE Building, Agnes Sjöbergin katu 2, Helsinki, Lecture room Walter.

Professor Martti Vaara, will serve as the opponent, and Professor Hannu Korkeala as the custos.

MSc Pradeep Kumar Kondadi will defend his doctoral dissertation entitled “Genomics and functional genetics of the zoonotic pathogen Helicobacter bizzozeronii” in the Faculty of Veterinary Medicine, University of Helsinki, on Friday 25th October 2013 at 12. The public examination will take place at the University Main Building, Fabianinkatu 33, Lecture room 5.

Assistant Professor Annmieke Smet, Ghent University, will serve as the opponent, and Professor Marja-Liisa Hänninen as the custos.

Encrine disrupting chemicals, foremost substances eliciting effects similar to estrogen (dubbed xenoestrogens), are common in our environment. However, the extent to which they exist in foodstuffs and industrially processed foods is still poorly known. In this study, professor Raimo Pohjanvirta and his group examined three batches each of 15 popular processed foods, purchased from a local supermarket, for their estrogenic activity. “In addition, we included 3 x 5 ready-to-eat snacks acquired from a hamburger place for comparison. The assay system consisted of yeast cells transfected with a luciferase reporter gene that became activated by estrogen receptor-alpha-mediated signal transduction.” says Pohjanvirta.

Industrially processed chicken and beef burgers exhibited high estrogenic activity

In the majority of the samples analyzed, estrogenic activity was low. An exception to this rule were industrially processed chicken and beef burgers and, in particular, pepper salami, in which they consistently found quite high activities in all three batches. A fact common to these three food items was that they all contained soy protein as an ingredient. In the great majority of other samples, soy had not been used in their manufacture. Because soy has been shown to contain isoflavones with potential for estrogenic activity such as genistein, they further analyzed two soy sauces by their assay system; both proved highly positive.

An intriguing finding was that chicken, beef or cheese burgers bought from a hamburger restaurant were devoid of estrogenic activity, despite the fact that they were also informed to contain soy. The reason for the discrepancy may lie in a quantitative difference or, in the case of supermarket burgers, antioxidants might conceivably have potentiated the activity. Since the health impacts of soy are arguable, from the health risk point of view it would be advisable to avoid frequent exposure to it; this is especially true for children whose endocrine system can be more vulnerable to endocrine disrupters than that of adults. Finally, they also examined the wrapping materials of food products because there is a suspicion that certain estrogenic plasticizers such as phthalates and bisphenol-A might leach from the wrappings into food. However, all these samples were negative in their assay.

Further studies are warranted

Based on their results, they concluded that the majority of Finnish commercial food products do not contain xenoestrogens in concentrations that could be detrimental to health. The researchers remind, however, that their sample composition was fairly confined and therefore further studies are warranted regarding, for example, dietary supplements.

Link to the article

Iyekhoetin Matthew Omoruyi, Grit Kabiersch & Raimo Pohjanvirta , Food Additives & Contaminants: Part A (2013): Commercial processed food may have endocrine-disrupting potential: soy-based ingredients making the difference, Food Additives & Contaminants: Part A, DOI: 10.1080/19440049.2013.817025

Iyekhoetin Matthew Omoruyi  & Raimo Pohjanvirta, Department of Food and Environmental Hygiene (Food and Environmental Toxicology Unit), Faculty of Veterinary Medicine, University of Helsinki, F-00014 Helsinki, Finland
Grit Kabiersch, Division of Microbiology, Department of Food and Environmental Sciences, Faculty of Agriculture and Forestry, University of Helsinki, F-00014 Helsinki, Finland

Professor, Vice-Rector Johanna Björkroth has been nominated as Scientific Editor of the Applied and Environmental Microbiology (AEM) published by the American Society for Microbiology (ASM).

The American Society for Microbiology (ASM) is the world’s oldest and largest life science membership organization. Society has been established in 1899, nowadays there are more than 39.000 members worldwide.

The Society publishes journals, of which Applied and Environmental Microbiology (AEM) is the most cited journal in the fields of microbiology, biotechnology and applied microbiology, with more than 86.000 citations. It has an Impact Factor of 3.678 according to the 2012 Journal Citation Reports®.

The term of the Scientific Editor is for 5 years. AEM emphasized professor Björkroth’s wide expertise not only in the area of food microbiology, but also tangential areas such as microbial physiology or the molecular microbiology. Björkroth’s preceding job as an Editorial Board Member was highly acknowledged, she started as an Editorial Board Member in 2002.

Professor Björkroth is leading a research group focusing on cold-tolerant lactic acid bacteria and enterobacteria causing food spoilage. The research group belongs to the Centre of Excellence in Microbial Food Safety Research (MiFoSa). She has published more than 100 articles in peer-reviewed scientific series and several book chapters, and supervised several postgraduate studies (PhD Thesis). Since 2008, she has served as a Vice-Rector of the University of Helsinki in charge of research, researcher training and innovation affairs.