| Nowadays,the food safety problems related to the fresh food have always broken out inChina.The issue of the fresh food safety,especially for organophosphorus pesticide residues,poses threat to the consumers' health.As the end of the food supply chain,the supermarketshave becoming the main channel for fresh food distribution.The food quality and safetymanagement of supermarket is at the primary stage because of the late starting.Therefore,theresearch on the quality and safety system for fresh food of supermarket and the method fordetermination of pesticides do not only have their theoretical significance,but also providessome practical advices on the quality and safety management for fresh food,and offers thequick,simple and economical method for the determination of pesticides.The paper clarified the problems of the fresh food management of supermarket throughthe analysis of Suguo supermarket.Basing on the economic analysis of the quality and safetyfor fresh food and the investigation of the fresh food quality and safety management ofdomestic supermarkets,the construction of fresh food quality and safety system ofsupermarket in China was discussed and the application of HACCP in the leaf vegetablesupply chain of supermarket was also researched in the paper.Beside these,in order toimprove the method for the determination of pesticides,the O,O-dimethylphosphorodithioate,which is the generic structure of methoxy organophosphorus pesticide,was used as the target determinate group to generate broad specificity polycolonal antibodies.Three haptens with different spacer-arm were synthesized and conjugated to BSA to be usedas immunogens to produce the antibodies.The broad specificity immunoassay was developedthrough selecting the combinations of antibody-coating antigen and optimizing the conditionsof experiment.The influence of the antigen heterology for the affinity of antibody and thesensitivity of the method was also studied.Through the research of this article,some beneficial conclusions have been drawn:(1)Basing on the analysis of Suguo supermarket and the investigation of fresh foodquality and safety management of supermarket,the construction of food quality and safetysystem of supermarket in China was discussed.The food safety management organizationshould be set independently.Begin with the cultivating of the production base,the manage measures should be established separately for the three mode of fresh food supply chains,including"Production base-Supermarket","Production base-Merchant-Supermarket"and"Production base,Farmers' corporate organization,individual farmer-Wholesalemarket-Supermarket".The devotion of equipments for cool chain should be increased and thepower of management should be improved.The standard of operation in every tache of thesupply chain should be done to standardize the action.The advanced method should beintroduced to develop the determination platform.The determination system should be set upby combining the supervision from supermarket and the determination from the third party.The system of tracing to the source basing on the development of technic and the databaseshould be developed.The supervision system should be constructed in every tache of thesupply chain supervised by the govemment,trade department,media and consumers.Finally,the fresh food quality and safety system of supermarket which is valuable for popularizationis formed.(2)The application of HACCP in the leaf vegetable supply chain of supermarket wasstudied according to the implement process of HACCP.Basing on the results of hazardanalysis,the critical control points were the tache of determination before carrying away fromproduction base and the tache of acceptance by supermarket.The critical limites of pesticides,heavy metals and sense inspection,the inspection procedure and the correction measure werealso established.Some correlative policy measures were recommended.(3)The O,O-dimethyl phosphorodithioate which is the generic structure of methoxyorganophosphorus pesticide was used as the target determinate group.Three haptens withdifferent spacer-arms were synthesized.1HNMR,13CNMR and MS spectra data supported allstructures of target molecules.The haptens were conjugated to carrier proteins forimmunogens and coating antigens by two coupling methods.UV-vis and IR spectral dataconfirmed the structures of the final conjugates.(4)The effect of antigen heterology on antibody affinity and immunoassay sensitivitywas also studied.The results showed as follows:The titer difference between homologousand heterologous was great.The heterology in spacer arm may be not available for theantigen recognition by antibodies generated from immunogen with simple spacer arm.Thetiter difference may be due to the different coupling methods resulting in different haptenloads and different influence in the space structure of protein.Antigen heterology is moreimportant for the antiserum immunized by the hapten with complicated spacer arm than thesimple spacer arm to improve the sensitivity of immunoassay.The hapten with simple spacerarm may be more conformable to produce the antibody with high sensitivity.(5)A general and broad class-specific enzyme-linked immunosorbent assay was developed for the O,O-dimethyl organophosphorus pesticides.The optimized conditions ofassay used antibody 3055 at a dilution of 1:6400,coating antigenⅡ-OVAa at 2μg/mL,andanalyte in 5% methanol-0.01 mol/L PBS buffer,pH is between 6.0～7.4.The IC50 values ofthe assay,under optimized conditions,were estimated to be 30.1 ng/mL for malathion,28.9ng/mL for dimethoate,88.3 ng/mL for phenthoate,159.7 ng/mL for phosmet,191.7 ng/mL formethidathion,324.0 ng/mL for fenitrothion,483.9 ng/mL for methyl parathion,and 788.9ng/mL for fenthion.Recoveries of malathion,dimethoate,phenthoate,phosmet andmethidathion from fortified Chinese cabbage samples ranged between 77.1% and 104.7%,theCVs were lower than 13.81%.This assay can be used in monitoring studies for themulti-residue determination of O,O-dimethyl organophosphorus pesticides.
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