Navigation Links
Pathogens in cheese

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.


Contact: Dr. Stephan Schmitz-Esser
University of Veterinary Medicine -- Vienna

Related biology news :

1. UTMB collaborates on program targeting potential bioterrorist pathogens Ebola and Marburg
2. Scientists learn how pathogens hack our immune systems to go undetected
3. Harvested rainwater harbors pathogens
4. Ants protect acacia plants against pathogens
5. New technique identifies pathogens in patient samples faster, in great detail
6. Study to identify functions of hypothetical genes in 2 infectious disease pathogens
7. Helper cells aptly named in battle with invading pathogens
8. Recent progress in gene-sensing strategies for rapid detection of foodborne pathogens
9. Sequencing tracks animal-to-human transmission of bacterial pathogens
10. March of the pathogens: Parasite metabolism can foretell disease ranges under climate change
11. New device better traps viruses, airborne pathogens
Post Your Comments:
Related Image:
Pathogens in cheese
(Date:10/29/2015)... , October 29, 2015 ... authentication company focused on the growing mobile commerce ... announces that StackCommerce, a leading marketplace to discover ... the Wocket® smart wallet on StackSocial for this ... ("NXT-ID" or the "Company"), a biometric authentication company ...
(Date:10/27/2015)... 2015 Munich, Germany ... technology (ASGM) automatically maps data from mobile eye tracking ... , so that they can be quantitatively analyzed with ... Munich, Germany , October 28-29, 2015. SMI,s Automated ... mobile eye tracking videos created with SMI,s Eye ...
(Date:10/26/2015)... and LAS VEGAS , Oct. 26, ... , an innovator in modern authentication and a founding ... the launch of its latest version of the Nok ... organizations to use standards-based authentication that supports existing and ... Authentication Suite is ideal for organizations deploying customer-facing applications ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... ... November 25, 2015 , ... A long-standing partnership between ... (OPBAP) has been formalized with the signing of a Memorandum of Understanding. , ... leaders Capt. Karl Minter and Capt. Albert Glenn Tuesday, November 24, 2015, at ...
(Date:11/24/2015)... ... November 24, 2015 , ... The United States Golf Association ... 2016 USGA Green Section Award. Presented annually since 1961, the USGA Green Section Award ... work with turfgrass. , Clarke, of Iselin, N.J., is an extension specialist ...
(Date:11/24/2015)... , ... November 24, 2015 , ... ... of the year and one of the premier annual events for pharmaceutical manufacturing: ... from 8–11 November 2015, where ISPE hosted the largest number of attendees in ...
(Date:11/24/2015)... ... 24, 2015 , ... The Academy of Model Aeronautics (AMA), led by its ... as Multirotor Grand Prix, to represent the First–Person View (FPV) racing community. , FPV ... embraced this type of racing and several new model aviation pilots have joined the ...
Breaking Biology Technology: