| Red jujube is the characteristic industry with the most resource advantages and development potential in Xinjiang.At the same time,it is also an important pillar to support the development of agricultural economy in southern Xinjiang.In recent years,"black spot"caused by Alternaria fungi has become the main disease of jujube industry in Xinjiang,causing an annual loss of more than 30%;Its mycotoxin pollution brings safety panic to consumers’consumption of jujube and its products.Therefore,mastering the species,content and pollution distribution of Alternaria toxin in jujube and evaluating its safety are urgent to ensure the sustainable and stable development of jujube industry in southern Xinjiang.In this project,combined with solid phase extraction technology,a method for the detection of Alternaria toxin in jujube by UPLC-MS/MS with QuEChERS as the core was established;The contamination level of Alternaria toxin in Xinjiang jujube and its products was analyzed;Combined with Chinese dietary data and referring to the toxicity threshold of Alternaria toxin,carry out dietary exposure assessment,risk description and risk classification of Alternaria toxin.In order to provide theoretical reference for consumers to eat jujube and its products,and lay a safe foundation for the steady and healthy development of jujube industry in southern Xinjiang.(1)In order to find a rapid and accurate method for the detection of Alternaria toxin in jujube samples,this study took solid and liquid jujube samples as the research object,and explored the UPLC-MS/MS toxin analysis technology based on solid phase extraction and QuEChERS.The results showed that Alternaria toxin in solid jujube samples was extracted with acetonitrile containing 1%acetic acid,4g anhydrous magnesium sulfate for water removal,1g sodium chloride for purification,acetonitrile methanol formic acid solution with a volume ratio of 70:29:1,0.1m M ammonium carbonate aqueous solution as mobile phase A,pure methanol as mobile phase B,gradient elution for 0～4.0min 20%A,4.0～5.6min 100%A,5.6～8.0min 20%A,and multi reaction monitoring mode scanning by electrospray ion source(ESI-),The recovery was in the range of 74.89%～98.04%,the relative standard deviation was less than 10%,and the correlation coefficient R~2of the standard curve was greater than 0.99.It was suitable for the detection of Alternaria toxin in solid jujube samples.In order to meet the detection requirements of Alternaria toxin in liquid jujube samples,when the p H of liquid jujube samples is 2.5,HLB LP extraction solid phase extraction column is used for purification and enrichment,0.1m M ammonium carbonate aqueous solution is used as mobile phase A,pure methanol is used as mobile phase B,gradient elution is carried out for0～4.0min 20%A,4.0～5.6min 100%A,5.6～8.0min 20%A,and scanning is carried out by electric spray ion source(ESI-)multi reaction monitoring mode.The recovery is within the range of 74.11%～99.83%,The relative standard deviation is less than 10%,and the correlation coefficient R~2of the standard curve is greater than 0.99.(2)In order to understand the pollution of Alternaria toxin in red jujube in southern Xinjiang,this study took red jujube products of different production areas,different varieties,different years,different processing methods and different forms in southern Xinjiang as the research objects,and determined the Alternaria toxin by uplc-ms/ms method established in the early stage,and analyzed the types and contents of Alternaria toxin.The results showed that the highest content of Alternaria toxin AOH in Jun jujube produced in Aksu region in 2020 was 53.22μg/kg,the highest content of Alternaria toxin Te A in grey jujube produced in Kashi region in 2021 is 10.76μg/kg.During the three years from 2019 to 2021,Alternaria toxin ame and Te N were not detected in the unprocessed raw materials Jun jujube and grey jujube from the four main jujube producing areas of Kashgar,Hotan,Aksu and Bazhou in southern Xinjiang.The highest detection rate of Te A in dried jujube products was 96.31%,and the content was6.16～9.70μg/kg;The highest ALT content in fried jujube products was 28.43～399.64μg/kg;AOH content in sugar preserved jujube products is 34.76～98.61μg/kg;Only Alternaria toxin Te A was detected in fermented jujube products and extracted jujube products,and the content was 125.31～129.07 respectivelyμg/kg、121.73～132.86μg/kg.(3)In order to clarify the hazard level of Alternaria toxin in red jujube to people,based on the Toxtree toxicity prediction platform and T.E.S.T toxicity assessment software,combined with the previous determination results of the types and contents of Alternaria toxin in red jujube and red jujube products in southern Xinjiang,this paper carries out risk description,risk level division and dietary exposure assessment.Alternaria toxin Te A and AOH have binding effects on protein and DNA.The risk level of Te A is genotoxic careinogens and that of AOH is Cramer class III;The PDE range of Alternaria toxin in adults(60kg body weight)is 19.30～25.65μg/d,equivalent to eating 3.34～3.71kg red jujube products contaminated by Alternaria toxin every day,indicating that the dietary exposure risk of Alternaria toxin in red jujube products is still within the acceptable range of adults. |
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