A Comparative Analysis of Methods (LC-MS/MS, LC-MS and Rapid Test Kits) for the Determination of Diarrhetic Shellfish Toxins in Oysters, Mussels and Pipis

Rapid methods for the detection of biotoxins in shellfish can assist the seafood industry and safeguard public health. Diarrhetic Shellfish Toxins (DSTs) are produced by species of the dinoflagellate genus Dinophysis, yet the comparative efficacy of their detection methods has not been systematically determined. Here, we examined DSTs in spiked and naturally contaminated shellfish–Sydney Rock Oysters (Saccostrea glomerata), Pacific Oysters (Magallana gigas/Crassostrea gigas), Blue Mussels (Mytilus galloprovincialis) and Pipis (Plebidonax deltoides/Donax deltoides), using LC-MS/MS and LC-MS in 4 laboratories, and 5 rapid test kits (quantitative Enzyme-Linked Immunosorbent Assay (ELISA) and Protein Phosphatase Inhibition Assay (PP2A), and qualitative Lateral Flow Assay (LFA)). We found all toxins in all species could be recovered by all laboratories using LC-MS/MS (Liquid Chromatography—tandem Mass Spectrometry) and LC-MS (Liquid Chromatography—Mass Spectrometry); however, DST recovery at low and mid-level concentrations (0.86 mg/kg) was higher (60–262%). While no clear differences were observed between shellfish, all kits delivered an unacceptably high level (25–100%) of falsely compliant results for spiked samples. The LFA and the PP2A kits performed satisfactorily for naturally contaminated pipis (0%, 5% falsely compliant, respectively). There were correlations between spiked DSTs and quantitative methods was highest for LC-MS (r2 = 0.86) and the PP2A kit (r2 = 0.72). Overall, our results do not support the use of any DST rapid test kit as a stand-alone quality assurance measure at this tim

The Hillarys Transect (3): Optical and chlorophyll relationships across the continental shelf off Perth

An interdisciplinary study of the waters across the continental shelf off Perth, Western Australia, has provided the first detailed climatology of the physical, chemical, optical, and biological processes across the shelf. In support of this work, remote-sensing data were utilised to provide a broad view of the spatial and temporal chlorophyll concentration dynamics, to support in situ observations, and to help "fill the gaps" inherent in in situ point sampling. In situ validation of remote-sensing products was carried out monthly off Perth over a 27-month period. Biological and physical measurements were made along a 40 km east-west transect, 20 km north of Perth. Results of the study have shown that in water deeper than 30-35 m, and where viewing conditions were suitable, the in situ measurements of chlorophyll concentration were within the 35% uncertainty of the SeaWiFS product. An increase in the in situ measurements of near-coastal chlorophyll concentration was evident during the 1998 winter period (May-July), but the apparent seasonal increase was not evident in the in situ data for 1997. The SeaWiFS chlorophyll concentration estimates have been used to show the seasonal fluctuation of chlorophyll concentration in Perth coastal waters from November 1997 to the end of 2004. The remotely sensed data show a clear seasonal cycle, with maximum chlorophyll concentration occurring during May, June and July for waters off Perth. Also evident from the remotely sensed data was an increase in water column light attenuation during winter, coincident with the increase in chlorophyll concentration. The potential now exists to further develop remote-sensing techniques and to integrate remotely sensed products into routine water-quality monitoring programmes for WA waters