Shellfish monitoring for lipophilic phycotoxins in France, recommendation for an updated sampling strategy

In France, the sampling strategy for the official monitoring of lipophilic phycotoxins in bivalve shellfish relies on the definition of risk areas and high risk periods, during which a systematic weekly analysis of toxins in shellfish is performed. Since 2010, high risk periods are defined as follows: the occurrence of one result above the European regulatory limit (160 μg equivalent okadaic acid/kg shellfish) over the last 3 years leads to that month being considered a high risk period. This definition was established according to a statistical analysis of the official monitoring results for the period 2003-2008, based on the mouse bioassay (MBA) as the official analytical method. As of the 1st January 2010, the MBA has been replaced by LC-MS/MS. In 2014, a new statistical analysis was performed, based this time on results for the period 2010-2013 for which quantitative LC-MS/MS data are available. We tested the robustness of the definition set in 2010 and identified a new methodology to improve our sampling strategy for lipophilic toxins in bivalve shellfish, based on Bayesian inference