Detection of Paralytic Shellfish Toxins in Mussels and Oysters using the Neogen™ Qualitative Lateral Flow Immunoassay: Single laboratory validation and Collaborative Study

The Neogen™ Kit, a qualitative lateral flow immunoassay, modified to improve detection of GTX1,4 and GTX2,3 was shown to be the best commercially available rapid screening test for bivalves affected by Alexandrium tamarense... [ view full abstract ]

The Neogen™ Kit, a qualitative lateral flow immunoassay, modified to improve detection of GTX1,4 and GTX2,3 was shown to be the best commercially available rapid screening test for bivalves affected by Alexandrium tamarense in Tasmania, Australia. A validation study was undertaken following AOAC International guidelines for qualitative binary chemistry methods applied to four naturally contaminated mussel and oyster homogenates containing different PST profiles. Appropriate selectivity to known toxins in bivalves was demonstrated. In the single lab validation the kit consistently detected PST toxins in matrix with a probability of detection (POD) of 1.0 at the regulatory level (0.8 mg STX·2HCl eg/kg). No significant differences were seen between kit production lots. A collaborative study involving 16 laboratories was performed using both the standard kit and modified protocols.  Both methods showed good homogeneity across all laboratories. The mean POD at 0.8 mg STX·2HCl eq/kg in mussels and oysters using the standard protocol was 0.966 and 0.997, and using the modified protocol 0.968 and 0.969, respectively. The LOD in mussels was 0.308 mg STX·2HCl eg/kg with the standard protocol and 0.682 mg STX·2HCl eg/kg with the modified protocol, while for oysters it was 0.701 and 0.724 mg STX·2HCl eg/kg for standard and modified protocols respectively. The results show the method is acceptable for regulatory screening purposes for oysters in accordance with EC directives, with the standard protocol providing a probability of a negative response at the regulatory level of < 0.034 on 95% of occasions.