Research In China's Coastal Shellfish Biotoxins

Contamination o f s hellfish p roducts by different b iotoxins i s o ne o f the most important issues leading to the concern of food safty, which directly related to the health of seafood consumers. Therefore, it's important to carry on the reseaches on biotoxins contamination in shellfish, especially in China, where the shellfish mariculture industry has become more and more important. In this thesis, detection methods targeted on different biotoxins have been developed and shellfish contamination status is evaluated based on the analytical results. Shellfish samples collected from Chinese coast for a one-year duration have been analyzied with High Perfomance Liquid Chromatography (HPLC) for paralytic shellfish toxins (PSTs). Based on the analytical results of the toxin content and profile, the PSTs contamination status has been roughly evaluated. After that, the contamination status in Lianyungang area was further studied through the analysis of shellfish samples collected during a three-month period, with intensified sampling frequency and species. Both of the studies found the evidence of PSP contamination in some shellfish samples, but the contaminattion rate is relatively low. The analytical results on dirrahetic shellfish toxins (DSTs) with HPLC suggested a higher contamination rate compared to those on PSTs. Both okadaic acid (OA) and dinophysis toxin (DTX1) were found in shellfish samples, but DTX1 contamination is more popular than OA. The inhibition of protein phosphatase enzyme (PP2a) activity by DSTs has been used to develop the sensitive and specfic assay methods for DSTs. The method was used in this thesis to assay the DSTs contamination in some samples collected from Lianyungang area, however, no positive sample was detected. The samples of Nassarius spp., which caused poisoning incidents in Fujian province and Jiangsu Province in 2002 and 2003, respectively, have been analyzed for the toxins responsible. The toxicity of the samples was evaluated with mouse bioassy protocol for assy of PSTs. However, the analytical results with HPLC expelled the involment of PSTs in the poisoning incidents.