In order to be able to classify a production or reinstallation zone, the competent authority must make an inventory of the sources of contamination that may affect the production area, as well as its quantity, seasonal variations, pluviometry, treatment of sewage water, circulation patterns, watercourse, bathymetry and tidal cycles. With all this information a bivalve mollusk sampling program must be established based on the results obtained in the study, so that the sampling is as representative as possible of the area. The competent authority must define a period for the revision of the analytical data of the bivalve samples in each zone so that the initial classification must be modified based on the results obtained. The group of experts with the European reference laboratory has published the guidelines to follow for this process: EU WGBM (2014, 2018a, 2018b).
The classification of the production zones is based on the results of the analytics of Escherichia coli in meat of bivalve mollusks by means of the method EN ISO 16649-3. The results are reviewed with the frequency indicated for the competent authorities.
Category A
80% of samples ≤ 230 Escherichia coli /100 g of meat and intravalve fluid
The remaining 20% ≤ 700/100 g of meat and intravalve liquid
Category B
90% of samples 4600 Escherichia coli /100 g of meat and intravalve fluid
The remaining 10% ≤ 46,000 Escherichia coli /100 g of meat and intravalve fluid
Bivalve mollusks from these areas can only be marketed for human consumption after being treated at a purification center or after reinstallation.
Category C
≤ 46000 Escherichia coli /100 g of meat and intravalve fluid
Bivalve mollusks from these areas can only be marketed after their reinstatement over a long period, so that they meet the criteria of area A.