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 Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care

nachricht Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>