| Violation of standard limits of pesticide residue is one of the most important issues for the quality and safety control of agro-product; generally, monitoring and regulation of the quality and safety of agro-products are basically dependent on the dietary exposure assessment and residue limit establishment. There should be different limit standards for pesticides in spinach according to the stage of production. By searching the international standards of pesticide residue limits in spinach, the status of standards for spinach and its product was analyzed. The dynamics of chlorpyrifos and other pesticide residues, transferring in spinach cultivation and processing was studied, and the theoretical maximum dietary intake (TMDI) of pesticides in Chinese spinach was also estimated. With the results of pesticide used in trial experiment and processing factor, some MRLs were proposed for raw spinach and its product. There are also some advices proposed for the pesticide limit establishment and pesticide control. The main conclusions of this study are as the following:The first, the status of pesticide residue limits for spinach was analyzed. There are different standards in different countries, and the quantities and ranges of MRLs are significantly diverse. There are about 321 MRLs for spinach in Japanese standard, however, the number of limit over 0.1 mg·kg-1 is about 163, which accounts for 50% of the total. The results show that there is more space for China to meet the requirement of Japanese positive list system for spinach export. There are about 303 MRLs for spinach and its analogue in European Union, only 163 MRLs especial for spinach, and there are more than 259 MRLs under 0.05mg·kg-1, which accounts for 85% of the total. The European Union standard is the mostly strict standard compared with others. The Codex Alimentarius Commission standard for spinach has about 78 MRLs, which is the less strict standard, and the number of limits under 0.1mg·kg-1 is only 10 which accounts for 12.8% of the total. There are about 55 MRLs in American standards and the number of limits under 0.1mg·kg-1 is 5% of the total, which is the least strict standard. In general, the strict degree of those standards is on the down order of EU, Japan, CAC and US. There is no herbicide limit for spinach in China, and the number is less than EU, Japan and US whose standards include pesticide, bactericide and herbicide, however. There was a long distance between spinach and its product in the variety and quantity of limits, and some advice were proposed to uniform the limits and judgement rule for Chinese spinach.Secondly, the dynamics of residues for chlorpyrifos and other pesticides during spinach cultivation and processing were studied. The residue of chlorpyrifos in soil could be uptaken by spinach, and the results showed that the quantity uptaken by root had a positive relationship with the residue in soil. So, before export enterprise planting spinach, the enterprise should affirm the pesticide residue in soil to avoid effecting spinach export. The results of pesticide residue dynamics in trial experiment showed that malathion had a more rapid degradation rate, the primary residue is only 4.5 mg·kg-1 under the limit of 8 mg·kg-1 for leafy vegetable in China. Chlorpyrifos was not proposed to be applied in spinach cultivation for insect control, because the existing limit is much stricter, not easy to achieve. There are no limits for propamocarb and metalaxyl in spinach, so is the other insecticide mixtures. The degradation and category of pesticide should be thought in the limits and safe intervals establishing. The residues of chlorpyrifos, fenvalerate and cypermethrin could be reduced by washing, blanching and drying so that exposure of residues via dietary intake could be reduced. The loss caused by frozen dry and hot air dry for pesticides in spinach had a relationship with solubility and vapor pressure, respectively. The loss of malathion during hot-air drying is more than 60%, however there is almost no loss during frozen dry for dimethoate in spinach. So different enterprises should use different pesticides based on their agro-product processing method to reduce the risk of pesticide.The third, the theoretical maximum dietary intake (TMDI) of pesticide in spinach was estimated for Chinese consumer. Dietary exposure assessment is the base for limit setting and risk management, and the risk index (%ADI) for 14 pesticides calculated by TMDI method was analyzed. The results showed that the risk index of synthetic pyrethroids was lower than organophosphorus pesticides, which is 12.2%-47.8%. However the index of dimethoate and diazinon is higher more than 243.6% and 121.8%, respectively, need to be further reduced by refined method. The MRL and pre-harvest interval is different, which was set by different methods. The EU method according with producing requirements is stricter compared with others.The MRL of chlorpyrifos, ?-cypermethrin, malathion, metalaxyl and propamocarb in spinach was 1,0.5,0.1,0.1 and 0.5mg·kg-1 respectively, and the safe interval was 7,7,3,14 and 14 days respectively, calculated with the method of EU. The processing factor of pesticide was firstly used in MRL setting for dehydrated spinach, based on the processing factor of chlorpyrifos, cypermethrin, fenvalerate and malathion and their MRLs in raw spinach, the MRLs for those pesticides established in dehydrated spinach was 5,6,3 and 3 mg·kg-1,respectively.Finally, some suggestions were proposed to set and control the pesticide residue limit in spinach and its product. The pesticides residue controlling and limit setting for spinach should be conducted in the whole with coherent, continuous and effective surveillance. The number of limit standards for spinach in different stages should be uniform, and there should be relevant values during the stage of soil, spinach planting and processing. The limit setting and conducting should be on the base of exposure assessment combined with agriculture practice and pesticide registration. All participants (producer, governor and consumer) need to be actively involved in the process of pesticide residue controlling for spinach which also need sound and effective laws and regulations.There are more active theoretical value and practical significance for pesticide residues controlling, limits setting and dietary exposure estimate in China, which are also significant to be used for the pesticide limit setting of other agro-products.
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