Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Pathogens in Cheese – Researchers Follow the Traces of Deadly Bacteria

21.03.2014

If food products are not produced in a hygienic environment, consumers can face the threat of dangerous pathogens. This is exactly what happened in 2009 and 2010 when two different strains of Listeria monocytogenes were found in the traditional Austrian curd cheese known as “Quargel”.

34 people were infected, and a total of 8 patients died. Experts from the University of Veterinary Medicine, Vienna analysed the genomes of the outbreak strains and were able to show that the strains displayed distinct properties and entered the food chain independently. The results were published in the journal PLOS ONE and will increase the understanding of outbreaks and their prevention.


Contaminated Quargel cheese caused several deaths in 2009 and 2010.

Photo: Kathrin Rychli/Vetmeduni Vienna

Listeria is a rod-shaped bacterium highly prevalent in the environment and generally not a threat to human health. One species however, Listeria monocytogenes, can cause listeriosis, a very dangerous disease. This pathogen can be present in raw milk and soft cheeses, smoked fish, raw meat and ready-to-eat products.

In Austria, health care providers are required to report all cases of listeriosis, which can be fatal particularly for patients with weakened immune systems. In 2009 and 2010, a dairy in Hartberg (Styria, Austria) produced Quargel cheese contaminated with Listeria monocytogenes leading to a multinational listeriosis outbreak in Austria, Germany and the Czech Republic, ultimately forcing the dairy to shut down. 

Detective work: finding the source

“I’m happy to report that we see relatively few cases of listeriosis here in Austria. When an outbreak occurs though, the disease has among the highest mortality rate of all food-borne illnesses”, explains lead author Kathrin Rychli from the Institute for Milk Hygiene, Milk Technology and Food Science at the University of Veterinary Medicine, Vienna. The Institute was involved in investigating the causes of the outbreaks back in 2009 and 2010. The culprits: two distinct bacterial strains which had not recently evolved from a common ancestor, and therefore entered the food chain independently. 

Genetics reveal the pathway

In their current study, the scientists sequenced and analysed the genomes of both strains, and assessed their virulence, the ability to infect cells. The samples were taken from listeriosis patients from the outbreak.

The first contamination event from June 2009 to January 2010 was attributed to one L. monocytogenes strain very effective at infecting epithelial cells of the intestine and liver cells. It contained additional four virulence genes, making it extremely invasive, and ultimately caused 14 cases resulting in 5 deaths.

A few months later in December 2009, the second L. monocytogenes strain emerged. It was particularly successful at infecting macrophages, important immune system cells. Over time, this highly infectious second strain replaced the first and by February 2010 had infected a total of 20 people, 3 of whom died. The average age of those taken ill was 70. 

Highest level of operational hygiene essential

Listeria expert and co-author Stephan Schmitz-Esser emphasizes the importance of cleanliness in production: “It is absolutely essential that appropriate disinfectants are used properly, lots of salt, and that possible food for the bacteria be limited. Any products listeria is found in must be recalled immediately. Recalls are very expensive for producers, and we need to do everything we can to prevent them.” Austria-wide the Institute for Milk Hygiene, Milk Technology and Food Science at the University of Veterinary Medicine, Vienna offers effective Listeria monitoring and a range of molecular and microbiological examination methods for the food industry. 

What are the symptoms of listeriosis?

Listeriosis generally manifests in healthy people with diarrhoea and stomach cramps, whereas the elderly, newborns and people with weakened immune systems are more susceptible. Listeriosis can result in septicaemia and meningitis. In pregnant women it can lead to miscarriage or stillbirth. Therefore, experts recommend pregnant women to avoid raw milk, raw meat and raw fish products. 

The article „Genome sequencing of Listeria monocytogenes “Quargel” listeriosis outbreak strains reveals two different strains with distinct in vitro virulence potential“, by Kathrin Rychli, Anneliese Müller, Andreas Zaiser, Dagmar Schoder, Franz Allerberger, Martin Wagner and Stephan Schmitz-Esser was published in the Journal PLOS ONE. DOI: 10.1371/journal.pone.0089964
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0089964

About the University of Veterinary Medicine, Vienna

The University of Veterinary Medicine, Vienna is the only academic and research institution in Austria that focuses on the veterinary sciences. About 1,200 employees and 2,300 students work on the campus in the north of Vienna which also houses five university clinics and various research sites. Outside of Vienna the university operates Teaching and Research Farms. http://www.vetmeduni.ac.at

Scientific Contact:
Dr. Stephan Schmitz-Esser
Institute of Milk Hygiene, Milk Technology and Food Science
University of Veterinary Medicine Vienna (Vetmeduni Vienna)
T +43 1 25077-3510
stephan.schmitz-esser@vetmeduni.ac.at

Released by:
Susanna Kautschitsch
Science Communication / Public Relations
University of Veterinary Medicine Vienna (Vetmeduni Vienna)
T +43 1 25077-1153
susanna.kautschitsch@vetmeduni.ac.at

Weitere Informationen:

http://www.vetmeduni.ac.at/en/infoservice/presseinformation/press-releases-2014/...

Dr. Susanna Kautschitsch | idw - Informationsdienst Wissenschaft

Further reports about: Food Hygiene Listeria Medicine Technology Veterinary immune monocytogenes strain strains virulence

More articles from Life Sciences:

nachricht Shark Tagged by NSU’s Guy Harvey Research Institute Is Apparently Enjoying Time in Warm, Tropical Waters
30.03.2015 | Nova Southeastern University

nachricht Misuse of Sustainability Concept May Lead to Even More Toxic Chemical Materials
30.03.2015 | Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Experiment Provides the Best Look Yet at 'Warm Dense Matter' at Cores of Giant Planets

In an experiment at the Department of Energy's SLAC National Accelerator Laboratory, scientists precisely measured the temperature and structure of aluminum as...

Im Focus: Energy-autonomous and wireless monitoring protects marine gearboxes

The IPH presents a solution at HANNOVER MESSE 2015 to make ship traffic more reliable while decreasing the maintenance costs at the same time. In cooperation with project partners, the research institute from Hannover, Germany, has developed a sensor system which continuously monitors the condition of the marine gearbox, thus preventing breakdowns. Special feature: the monitoring system works wirelessly and energy-autonomously. The required electrical power is generated where it is needed – directly at the sensor.

As well as cars need to be certified regularly (in Germany by the TÜV – Technical Inspection Association), ships need to be inspected – if the powertrain stops...

Im Focus: 3-D satellite, GPS earthquake maps isolate impacts in real time

Method produced by UI researcher could improve reaction time to deadly, expensive quakes

When an earthquake hits, the faster first responders can get to an impacted area, the more likely infrastructure--and lives--can be saved.

Im Focus: Atlantic Ocean overturning found to slow down already today

The Atlantic overturning is one of Earth’s most important heat transport systems, pumping warm water northwards and cold water southwards. Also known as the Gulf Stream system, it is responsible for the mild climate in northwestern Europe. 

Scientists now found evidence for a slowdown of the overturning – multiple lines of observation suggest that in recent decades, the current system has been...

Im Focus: Robot inspects concrete garage floors and bridge roadways for damage

Because they are regularly subjected to heavy vehicle traffic, emissions, moisture and salt, above- and underground parking garages, as well as bridges, frequently experience large areas of corrosion. Most inspection systems to date have only been capable of inspecting smaller surface areas.

From April 13 to April 17 at the Hannover Messe (hall 2, exhibit booth C16), engineers from the Fraunhofer Institute for Nondestructive Testing IZFP will be...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

World Conference On Regenerative Medicine 2015: Registration And Abstract Submission Now Open

25.03.2015 | Event News

University presidents from all over the world meet in Hamburg

19.03.2015 | Event News

10. CeBiTec Symposium zum Big Data-Problem

17.03.2015 | Event News

 
Latest News

BLS Cargo orders 15 multisystem locomotives

30.03.2015 | Press release

Shark Tagged by NSU’s Guy Harvey Research Institute Is Apparently Enjoying Time in Warm, Tropical Waters

30.03.2015 | Life Sciences

Antarctic Ice Shelves Rapidly Thinning

30.03.2015 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>