The Change Of 7 Typical Pesticide Residues In Edible Oil Processing And Dietary Risk Assessment

There is a continuing concern about the pesticide residues in food as a major issue in the food safety field.Edible oil is extensively produced and consumed in China.However,researches on the fate and residues of pesticide during edible oil processing are still limited.The current national MRLs on edible oil are all originated from Codex MRLs,which cannot be accurately reflected the risk of the human dietary intake of pesticides from edible oil in China.Seven pesticides that are widely used on the major oil crops in China were targeted to evaluate their fate in the processes of oilseed processing and frying.The impact of their residual behavior in the oil processing on the risk of dietary intake by Chinese residents was further assessed.By considering the actual processing data,theoretical processing factors and previous studies collectively,the dietary intake of fat-soluble pesticides that are applied on major oilseeds in China has been thoroughly assessed.The results could provide valuable data on pesticide registration of pesticide applied on oilseeds and also be valuable for the establishment of national MRLs in China.The main results of this study were summarized as follows:The analytical methods have been developed for chlorpyrifos,deltamethrin,methoxyfenozide and azoxystrobin in soybeans,chlorpyrifos,deltamethrin,methoxyfenozide,azoxystrobin and propargite in peanuts,and deltamehrin,iprodione and carbendazim in rapeseeds.The linearity of the methods in the range of 0.005-2 mg/L was well fitted;the recoveries of target pesticides in three matrices were between 72.2% and117.6%,the relative standard deviations were in the range of 1.3%-15.4%,and LOQ were0.01 mg/kg.The fate of seven pesticides during the oilseed processing and frying was investigated.The residues of 7 pesticides were decreased during the oilseeds drying process due to their volatilization and degradation.The pesticide residues in vegetable oil were significantly concentrated during the peanuts and soybeans pressing process,while the pesticides residues in the oil meal(solid residues)were generally low.The distribution of pesticides between in vegetable oil and oil meal has a clear correlation with the pesticide log Kow values.The pesticides have greater log Kow values were preferentially accumulated in the vegetable oil.However,this relationship was not observed in the rapeseed pressing process,and this may be due to the content of unsaturated fatty acids in different oils.Most of the pesticides residues were concentrated in the heating process during further edible oil processing(fried).The residues of several pesticides were reduced due to thermal instability.The decomposition of pesticides became obvious and the residue of most pesticides decreased with repeated frying process.As a result,the PF of the 7 pesticides in vegetable oil were all significantly less than 1.Pesticide residues were not significantly enriched in French fries after frying process.With the increasing in the number of frying,the pesticide residue gradually increased on French fries fried with peanut oil,while gradually decreased on French fries fried with soybean oil.This is maybe due to the fact that varied cooking temperature and duration between two oils.The pesticide residue in the French fries insignificantly changed when fried by the rapeseed oil.The assessment of dietary intake of 7 pesticides was studied using two types of dietary consumption data including both China and GEMS/Food.The risk of dietary intake of 7 pesticides increased by 0%-1.8% after consideration of processing factors obtained from processing studies,where the risk of dietary intake of chlorpyrifos and methoxyfenozide increased 1.8% and 1.65%,respectively.The risk of deltamethrin increased to 138.9% on the basis of the original unacceptable risk of 137.8%.The dietary intake risk increased by-0.1%-1.4% and 0.2%-9.1% after consideration of PFs obtained from literatures and theoretical calculation,respectively.The results suggested that the global GEMS / Food diet cluster data was not applicable to the dietary risk assessment of Chinese residents.The dietary intake assessment of all lipid-soluble pesticides registered in oilseeds crops in China was further evaluated based on the processing factors obtained from theoretical calculation,literatures of oil processing studies and extrapolation methods.The risk of dietary intake of pesticides increased by 0.04%-85.3% after consideration of the theoretical oilseeds PFs.Of which,15 pesticides with lower ADI(less than 0.01mg/kg bw)were particularly obvious with a increasing of 3.7%-85.3%,and there were 9 pesticides whose dietary intake risk exceeded 100 after oil processing.The dietary intake risk increased by-4.2%-31.2% after considering the PFs obtained or calculated from literatures studies.The comprehensive study on pesticide fate and residue in the edible oil processing is urgent for food safety and pesticide risk management.In the absence of processing data in China,the theoretical PF can be introduced to conduct the most conservative dietary risk assessment,and supplemented by the assessment based on literature study for reference.Once the above dietary intake risk exceeds one hundred,i.e.the risk is unacceptable,it is necessary to conduct processing study on the pesticide residues based on the actual situation of edible oil processing in China,and then estimate an accurate dietary risk to ensure that the application of pesticides would not bring unacceptable risk to consumers.