Aarhus Universitets segl

No. 100: Sanitary survey report 2: Nissum Bredning

Larsen, M.M., Jakobsen, H.H., Göke, C., Hendriksen, N.B., Rømer, J.K., Mohn, C. & Schultz, A.C. 2017. Sanitary survey rapport 2: Nissum Bredning. Aarhus Universitet, DCE – Nationalt Center for Miljø og Energi,112 s. - Teknisk rapport fra DCE - Nationalt Center for Miljø og Energi nr. 100. http://dce2.au.dk/pub/TR100.pdf 

Summary 

According  to regulation (EC) No 854/2004 of the European Parliament and of the Council of 29 April 2004 laying down specific rules for the organisation of official controls on products of animal origin intended for human consumption. classification of production areas for live bivalve mollusks etc.[1]and the associated sampling plan are required to be based on  so-called ‘sanitary surveys’. A sanitary survey is an assessment of the interactions between potential sources of microbial pollution, climate conditions and oceanography in the area. The EU Commission guidance for making a sanitary survey formed the basis for this report. However, in certain cases, the Danish practice for microbiological sampling frequency and classification made previously on the basis of this, as described in ‘muslingebekendtgørelsen’ is summarized in Appendix 13.  

The report covers production areas P1, P2, P3 and P4 within Nissum Broads. These production areas coincide currently with the algae monitoring area A1. For editorial reasons, the production areas are regarded under one term as ‘Nissum Broads’, acknowledging that the four production areas only include a proportion of Nissum Broards. The covered production areas within Nissum Broads are marked as A1 on the maps in this report. 

The report recommends a microbiological sampling plan consisting of re­commended selected sampling points and sampling frequencies for individual production areas. It is further discussed whether merging of production areas into fewer production areas could be considered in the future. This merge would then reduce the number of sampling points, without compromising food safety. 

The report is supported by public available data from monitoring of microbiological contamination in Nissum Broads, where the concentration of E. coli is determined in samples of mussels, etc. taken at different sampling points within each area. The report points to the most precautionary fixed sampling points for future monitoring.

In summary, the sanitary survey of Nissum Broads identifies an area that in general is a microbial homogeneous, stable and microbiologically clean area, and only rare occurrences of critical microbial contamination were found.

Summary of recommended sampling programme 

Based on an assessment of sources and transport routes for microbiological contamination (sanitary survey) verified against historical microbiological data in Nissum Broads, a microbiological monitoring programme is recommended for each of the production areas in Nissum Broads. 

In each of the recommended monitoring programmes, proposals for a sampling location, classification status (preliminary or permanent) and a sampling plan are outlined. 

Based on the results from the sanitary survey of the producing areas, supported by the historical data set of the number, frequency and E. coli concentration in samples, the production areas P1 and P2 are suitable for permanent classification with a future sampling frequency of at least 8 samples per year over a three-year period. In contrast, P3 and P4 do not reach the status of permanent classification, because of the insufficient number of data collected over the past three years, and due to general lack of data from the year 2016. For these areas to go from a status of preliminary to permanent classification, it will be necessary to collect 12 samples over six months or 24 samples over 3 years. 

The report is divided into main chapters, which provide a summary of identified microbiological contaminants. The main chapters take the starting point in appendix 2-10. Appendix 11 is a detailed review of all historical microbiological data from mussel monitoring consisting of the fishery’s own-check and the Danish Veterinary and Food Administration’s[2] verification projects of the industry´s microbial monitoring. It is decided that a so-called ‘shoreline survey’ is unnecessary because all possible sources of sanitary contamination are described in the sewage plans for the cities in the area, the beach water quality monitoring and in the analyses of the Ministry of Environment and Food under the auspices of the Water Framework Directive.


[1] Include live bivalve mollusks, echinoderms, tunicates and gastropods.

[2] Fødevarestyrelsen.