First observation of domoic acid and its isomers in shellfish samples from Shandong Province,China

A total of 133 shellfish samples were collected in seven cities of Shandong Province,China,from May to October,2019.The domoic acid(DA)concentrations were determined by liquid chromatographytandem mass spectrometry(LC-MS/MS),and their distribution characteristics were investigated.DA concentration was detected high in over 1/3(36.1%)of the samples of four kinds of shellfish in all three seasons in range from 0 to 102μg/kg.The highest DA concentrations were 102,101,36.7,and 10.2μg/kg in Crassostrea gigas,Chlamys farreri,Mactra veneriformis,and Mytilus edulis,respectively.Geographically,Yantai(22.0μg/kg)and Weihai(16.9μg/kg)showed relatively high concentrations of DA,whereas Rizhao and Dongying presented only 0.85-and 1.76-μg/kg DA,respectively.DA concentrations in the shellfish samples were strongly related to seasonal changes,being significantly higher in autumn and summer than that in spring.The DA risk exposure assessments indicate that dietary seafood consumption did not pose a health threat to general human population.In addition,three isomers(isoA,isoD,isoE)and 5′-epimer DA were detected in 3.00%-15.80%of the shellfish samples.This study is the first to observe DA and its isomers in shellfish samples of Shandong Province.The results demonstrate that DA contamination is very common and should be continuously monitored.

Thermal processing induced release and degradation of paralytic shellfish toxin from mussels Mytilus edulis

Understanding the risk factors associated with shellfish consumption is a relevant public health concern because of the potential adverse ef fects of paralytic shellfish toxins(PSTs).This work aims to study the effects of the five most common heating treatments(steaming,boiling,frying,water-bath heating,and microwaving),for different processing times and temperature/power settings,on the content of PSTs in mussels(Mytilus edulis)collected in Qinhuangdao,China.The toxin concentration,removal percentages,and toxin distribution in the cooking liquor and meat were examined.The five processing modes effectively accelerated toxin release into the cooking liquor.The average percentage removal was 73.53%±16.50%from tissues.Microwaving led to the most significant toxin degradation among the methods tested.These findings should facilitate risk assessment of PSTs in mussels.