| In recent years,food poisoning incidents caused by bivalve molluscs occurred frequently in Fujian province,the aquatic product consumption has a large proportion in resident'daily diet,therefore the edible security of aquatic product is now deeply concerned.So,detection methods for Diarrhetic shellfish poisons?DSP?and Paralytic shellfish poison?PSP?in bivalve molluscs had been developed by ultra performance liquid chromatography-mass/mass spectrometry?UPLC-MS/MS?,The pollution status of bivalve molluscs in Fujian Province was analyzed by detecting the actual sample,and then,the effects of cooking,low temperature pickling and cooking after low temperature pickling on the elimination of PSP were also investigated to achieve the processing factor.Finally,the dietary exposure assessment of PSP was conducted by the point estimates in bivalve molluscs.The main conculsions are as follows:1.Determination of diarrhea shellfish poisons by ultra performance liquid chromatography-mass/mass spectrometry?UPLC-MS/MS?in bivalve molluscs.The samples were extracted by methanol and separated on a reversed phase ACQUITY UPLC BEH C18?1.7?m,2.1mm×100mm?column with acetonitrile-0.01%ammonium hydroxide as the mobile phase.The free toxins?AZA1,AZA2,AZA3,PTX2-b,OA,DTX1,DTX2,YTX and hYTX?in the sample were detected under positive and negative multiple reactions monitoring?MRM?mode through polarity switching between time segments.When any one or more toxins of OA,DTX1 or DTX2 were positive in the sample,the esterified OA,DTX1 and DTX2 were converted to the free form by alkaline hydrolysis and their hydrolyzed toxins were determined by UPLC-MS/MS method.The average recoveries ranged from 85.1%to 96.7%at three spiked concentrations with the relative standard deviation?RSD?of 2.76%to 4.18%.The detection limit?LOD?ranged from 4.4?g/kg to 9.9?g/kg.The quantification limit?LOQ?ranged from 14.7?g/kg to 33.0?g/kg.This method meets the requirements of analytical methodology and is suitable for the analysis and detection of actual samples.2.Determination of paralytic shellfish poison by ultra performance liquid chromatography-mass/mass spectrometry?UPLC-MS/MS?in bivalve molluscs.The sample were extracted by 80%acetonitrile?containing 0.1%formic acid?,cleaned up using an Oasis?R HLB extraction cartridge?500mg/6mL?and separated on TSK-Gel Amide-80?5?m,2.0mm×150mm?column with acetonitrile-Ammonium formate buffer solution?each containing 0.1%formic acid?as a mobile phase.12 kinds of paralytic shellfish poisoning?STX,NEO,dcSTX,GTX1,GTX2,GTX3,GTX4,GTX5,C1,C2,dcGTX2,dcGTX3?and intermediate metaboliteswere?M1-5?detected by UPLC-MS/MS under positive and negative MRM mode through polarity switching between time segment.The average recoveries ranged from 81.3%to 99.8%at three spiked concentrations with the relative standard devation?RSD?ranged from 2.02%to5.36%.The detection limit?LOD?ranged from 1.03?g/kg to 3.98?g/kg.The quantification limit?LOQ?from 3.43?g/kg to 13.25?g/kg.This method meets the requirements of analytical methodology and is suitable for the analysis and detection of actual samples.3.In this study,the contamination of shellfish in bivalve shellfish in Fujian province was tracked and detected in 2016 and 2017 at the high incidence period of red tide in 6-8 months.The conclusions can be drawn as follows:?1?The detection rate of DSP in 2016 and 2017 in bivalve molluscs were 7.60%and 10.74%,respectively.From the monitoring results,it can be seen that the detection rate of DSP in bivalve molluscs in Fujian Province is relatively low.Most of the detected samples are mussels collected in June,while DSP samples are not detected in July and August or its DSP content below the detection limit.?2?In 2016,Fujian Province did not contain PSP in its bivalves or its content was below the detection limit.In 2017,the detection rate and over-standard rate of PSP in bivalve molluscs were 19.01%and 65.22%respectively.From the monitoring results,It can be seen that,except for the period of red tide,bivalve molluscs in Fujian Province without PSP or its content in the below the detection limit.When the red tide occurs,the content of paralytic shellfish toxins in bivalve molluscs increases sharply,Which can endanger the lives of people.Therefore,it is suggested that the relevant departments should strengthen the supervision of the market in the high incidence period of red tide in 6-8 months each year to ensure people's diet and life safety.4.The effect of cooking,low temperature pickling and cooking after low temperature pickling on the elimination of PSP were also investigated to achieve the processing factor.The results showed that the processing factors of paralytic shellfish poison in three processing methods are 0.234-0.749,0.096-0.767 and 0.026-0.697,the degradation rates are 25.10%-76.62%,23.29%-90.37%and 30.33%-97.45%,respectively.It is concluded that the best cooking process of bivalve shellfish is:with1%dietary alkali?sodium carbonate?low temperature pickled 3h after washing with water,cooking time is at least 8min.5.Without considering the processing factors,the acute dietary exposure risk values of PSP in bivalve molluscs in June,July,August were 0.794-2.310,0.097-0.293and 0.012-0.037 respectively,which in June among women aged 14-17year-olds%ARFD values was 0.764,the other age groups,%ARFD values were greater than 1,indicating that the%ARFD was not acceptable for bivalves molluscs in red tide occurred.In July and August,The%ARFD were less than 1,belonged to the safe level.The%ARFD to PSP in bivalve molluscs was compared between men and women.The results showed that the%ARFD of men was higher than that of women.considering the processing factors,the acute dietary exposure risk values of PSP in bivalve molluscs were 0.002-0.464,as it was less than 1,belonged to the safe level,processing could reduce the dietary intake risk of PSP in bivalve molluscs. |
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