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National Reference Laboratory for Monitoring Bacteriological and Viral Contamination of Bivalve Molluscs

Shellfish (clams, oysters) may be contaminated with human pathogenic bacteria and viruses. Bacterial contaminants are mainly belonging to the genus Vibrio, whereas noroviruses and hepatitis viruses dominate as viral contaminants. Vibrios can cause diarrhea in humans, but they can also lead to extraintestinal infections and blood poisoning. Noroviruses can cause gastroenteritis and infections with hepatitis A and E viruses can lead to inflammation of the liver. For reasons of precautionary consumer protection shellfish harvesting areas are, therefore, subject to hygiene control. The germ count of shellfish is measured and they are examined for pathogens. Depending on the outcome of these controls, shellfish are either released for consumption or protective measures have to be carried out. Furthermore, random samples are also taken of shellfish intended for human consumption within the framework of import procedures and the retail trade.

The main area of research of the BfR "National Reference Laboratory for monitoring bacteriological and viral contaminantion of bivalve molluscs" is the development, evaluation and validation of methods for the detection of bacteria and viruses in shellfish.

Research areas:

  • For the fast, sensitive and specific detection of humanpathogenic vibrios found in shellfish real-time polymerase chain reaction (PCR) techniques are being adapted for routine testing. Furthermore, for epidemiological studies PCR typing methods are required which permit the discrimination of single isolates of the same species.
  • Vibrios often produce toxins of which haemolysins play a prominent role in gastrointestinal disorders. Cell biology techniques are developed to allow a risk assessment of foodborne Vibrio isolates as potential human pathogens.
  • There are no tissue culture methods for routine virus detection at the present time as the corresponding viruses cannot yet be cultivated at all or only with great difficulty. Research on the improvement of cell culture systems for propagation of hepatitis viruses shall facilitate the standardized production of reference material and enable the determination of their infectivity.
  • For the reliable and sensitive virus detection in food molecular biological methods are to be established and updated in line with the latest scientific findings. This mainly concerns the use of real-time RT-PCR methods, which also allow the quantification of virus particles.
  • The preparation of samples for the corresponding molecular biological tests is of particular interest because of the frequently low virus concentration and the presence of inhibitors in shellfish that can impede virus nucleic acid detection using PCR analysis. Various existing methods for nucleic acid extraction are compared and the corresponding methods validated..
  • Comparative tests of the various national laboratories are conducted at regular intervals.


Das Bundesinstitut für Risikobewertung

Tasks of the NRL Monitoring Bacteriological and Viral Contamination of Bivalve Molluscs

The tasks of the National Reference Laboratory for Monitoring Bacteriological and Viral in Bivalve Molluscs include Co-ordination of the activities of the laboratories which are responsible in...

External Links

European Community reference laboratory (CRL) for monitoring bacteriological and viral contamination of bivalve molluscs



Contact person Virology
Prof. Dr. Reimar Johne (Leiter)



Contact person Virology
Dr. Eva Trojnar (stellvertr. Leiterin)



Contact person Bakteriology
Dr. Eckhard Strauch (Leiter)




Contact person Bakteriology
Dr. Stefan Hertwig (stellvertr. Leiter)




Federal Institute for Risk Assessment (BfR)
NRL for Monitoring Bacteriological and Viral Contamination of Bivalve Molluscs
Diedersdorfer Weg 1
12277 Berlin




Our Mission Statement

"Science to serve humanity" is the guiding principle of BfR.