UK National Reference Laboratory (NRL) for foodborne viruses and bacteriological contamination of bivalve molluscs

Providing information and guidance on public health related monitoring of bivalve shellfish and other foods

Viruses are important causes of foodborne illness with transmission of many different viruses including norovirus, hepatitis A virus and hepatitis E virus linked to consumption of contaminated food. The foodstuffs most commonly implicated in viral illness include bivalve molluscs and fresh produce (fruit and vegetables), but a wide variety of other foods including meat and processed foods have also been implicated in cases. Outbreaks of viral illness due to contamination of the surfaces of foods, or food preparation surfaces by for example infected food handlers are also common.  

In addition to viruses, faecal contamination of bivalve mollusc growing waters also presents a risk of bacteriological contamination. In EU legislation an end product standard for Salmonella spp. in bivalve shellfish protects the consumer. Meanwhile Escherichia coli (E. coli) is used as an indicator of faecal contamination, and included in both end product standards and rules for classification of bivalve mollusc growing waters.

In the EU, responsibility for ensuring the quality and consistency of methods relevant to foodborne viruses and bacteriological contamination of bivalve molluscs is split between four European Union Reference Laboratories (EURLs):

  • EURL for foodborne viruses
  • EURL for Escherichia coli
  • EURL for Salmonella
  • EURL for marine biotoxins and classification and monitoring of bivalve mollusc production areas

Following designation of an EURL, the competent authority in each EU member state is responsible for designating one or more corresponding national reference laboratories (NRLs), which:

  • co-ordinate the activities of other official laboratories in that state
  • represent the views of the state's laboratories at the European level

In the UK, the competent authority responsible for the implementation of the EU food safety Regulations is the Food Standards Agency (FSA). That agency, in turn, has designated Cefas' Weymouth laboratory as the UK NRL for foodborne viruses and bacteriological contamination of bivalve molluscs, responsible for NRL functions within the networks of the four EURLs listed above.

NOTE: The Cefas Weymouth Laboratory is one of multiple UK NRLs appointed within three of the four networks above. The other NRLs appointed by FSA are:

  • The Agri-Food & Biosciences Institute (AFBI) for marine biotoxins
  • Public Health England (PHE) for Salmonella and E.coli

NRL Responsibilities

Articles 100-101 of Regulation (EU) 2017/625 stipulates that NRLs will:

  • collaborate with the European Union reference laboratories, and participate in training courses and in inter-laboratory comparative tests organised by these laboratories; 
  • coordinate the activities of official laboratories with a view of harmonising and improving the methods of laboratory analysis, test or diagnosis and their use; 
  • where appropriate, organise inter-laboratory comparative testing or proficiency tests between official laboratories, ensure an appropriate follow-up of such tests and inform the competent authorities of the results of such tests and follow-up; 
  • ensure the dissemination to the competent authorities and official laboratories of information that the European Union reference laboratory supplies;
  • provide within the scope of their mission scientific and technical assistance to the competent authorities for the implementation of multi-annual national control plans and of coordinated control programmes; 
  • where relevant, validate the reagents and lots of reagents, establish and maintain up-to-date lists of available reference substances and reagents and of manufacturers and suppliers of such substances and reagents; 
  • where necessary, conduct training courses for the staff of official laboratories; 
  • assist actively the Member State in the diagnosis of outbreaks of foodborne diseases and in case of non-compliance of consignments, by carrying out confirmatory diagnoses, characterisation and epizootic or taxonomic studies on pathogen isolates;
  • in the case where more than one national reference laboratory for a European Union reference laboratory is appointed, work closely together with the other national reference laboratories so as to ensure efficient coordination between them, with other national laboratories and with the European Union reference laboratory.