Norovirus (NoV) outbreaks are often linked to the consumption of (raw) oysters. Bivalve molluscs have the ability to filtrate and accumulate NoV particles from faecal contaminated water.
By EU regulation, shellfish are analysed on E. coli levels, as an indicator for faecal contamination of production waters. However, this may not be reliable to determine contaminations of NoV in shellfish. Therefore a European baseline study on the prevalence of norovirus in oysters is organized by EFSA.
The EFSA selected five production areas and three dispatch centres for the Netherlands. The study takes place for a period of two years and samples are collected every two months.
The Netherlands have decided to expand the survey to get more information on national level. All 14 active Dutch production areas are included. Oysters are tested in the selected areas by EFSA. In the additional areas, the shellfish with the highest production volume are selected: oysters, mussels, cockles and razor clams.
In addition to the presence and concentrations of norovirus, hepatitis A and E. coli concentrations will be analysed in the same sample. Therefore, a complete overview of contamination of E. coli in relation to norovirus could be made.
The organization in the Netherlands is carried out by ‘The Dutch Food and Consumer Product Safety Authority’ (NVWA) in cooperation with the ‘National Institute for Public Health and the Environment’ (RIVM). NVWA is responsible for data reporting and sampling in corporation with Wageningen Marine Research.
RIVM is performing the E.coli, norovirus and Hepatitis A analyses.
