The European Food Safety Authority (EFSA) has concluded that a proposed threshold of 4000 micrograms of okadaic acid (OA) equivalents per kilogram in whole queen scallops (Aequipecten opercularis) cannot be endorsed based on a study by the French Agency for Food, Environmental and Occupational Health & Safety (ANSES). In a statement published on 29 June 2026, EFSA identified key limitations in the ANSES study, including a restricted number of samples and uncertainty about whether the relationship between OA levels in muscle versus whole scallops would hold at higher concentrations. The proposed threshold was intended to ensure that after sanitary shucking—removal of the hepatopancreas and other tissues—the edible adductor muscle would comply with the EU regulatory limit of 160 micrograms OA equivalents per kilogram. EFSA also provided recommendations on sampling schemes for shucked scallops, noting that the number of individual scallops needed in a pooled sample to classify batches as compliant or non-compliant depends heavily on the mean contamination level and variability.
The assessment was requested by the European Commission following a 2021 EFSA opinion on shucking of scallops contaminated with lipophilic toxins, which had found it impossible to retrieve a safe shucking level of OA for A. opercularis. In that earlier opinion, EFSA had evaluated the ANSES study but could not endorse a safe threshold. The new statement notes that no new occurrence data were submitted for the current assessment. The ANSES study results indicated that shucking was effective and provided compliant edible parts under the specific conditions studied, but the proposed limit of 4000 micrograms OA eq/kg is substantially higher than the highest whole-scallop level observed in the study (approximately 900 micrograms OA eq/kg). EFSA concluded that it is unknown whether the relationship between OA levels in muscle versus whole scallops would remain unchanged at higher concentration levels, and therefore the threshold cannot be endorsed based on the ANSES study alone. On sampling, EFSA advised that a target threshold of 80 micrograms OA equivalents per kilogram in edible tissue—half the regulatory limit—could be used as a precautionary measure to ensure batch compliance, but the required sample size depends on contamination variability.