The Monitoring Of Organophosphorus Pesticide Residues In Citrus And Evaluation Of The Impact Of Handling And Processing

China is the largest producer and consumer of fresh citrus in the world.In recent years,with the wide use of pesticides,the quality and safety of citrus is not optimistic,which shows high detection rate and over standard rate of agricultural residues,while organophosphorus pesticides are often used to control diseases and insect pests in the process of citrus growth and storage.Therefore,it is necessary to make statistics on the use of organophosphorus pesticides in citrus and analyze the change trend of pesticide residues under storage and various treatment conditions.The paper is divided into two parts.One is to take the monitoring results of organophosphorus pesticides in Citrus of the author's unit from 2016 to 2019 as samples,totaling 2047,to analyze the detection and exceeding of organophosphorus pesticides,and to discuss the classification of orange,lemon,orange and grapefruit,at the same time to screen out the high-frequency detection of pesticides for further research;the other is to select the three kinds of oranges,orange and grapefruit that are commonly eaten by the public as samples Matrix,through the addition of recovery method,the addition amount is 0.4 mg / kg,to study the matrix effect of high-frequency detection of organophosphorus pesticides in three types of matrix,and analyze the effect of seven different treatment methods,such as heating,refrigeration,freezing,acid-base treatment,pasteurization(simulation),enzyme treatment and milk addition,on the high detection of organophosphorus pesticide residues in three types of citrus.The main results are as follows:(1)The results of screening and statistical monitoring are as follows: the total physical examination rate of organophosphorus pesticides is 10.01%,and the total over standard rate is 2.25%.Among them,the detection rate from high to low is chlorpyrifos > hydrothion > propionofos > Triazophos > Omethoate > acephate,and the over standard rate from high to low is hydrothion > propionofos > Omethoate;the detection rate and over standard rate of organophosphorus pesticides of different citrus species are from high to low The lower order was orange > lemon > Orange >grapefruit.(2)Matrix effect analysis: chlorpyrifos,amifos,probromophos and Triazophos were significantly different in the same matrix of different pesticides,while amifos and probromophos were significantly different in orange and grapefruit matrix;for the same pesticide,only probromophos was significantly different in orange matrix and the other two matrices.(3)The residue and stability of chlorpyrifos were higher than those of amifos,albromophos and Triazophos in all three kinds of Citrus substrates.(4)Alkali treatment has obvious degradation effect on hydrothione and probromophos,especially when pH = 12,the hydrothione is completely degraded in three kinds of substrates,and the residual amount is 0%.Probromophos is only a little residual in two kinds of substrates,orange and orange,and the residual amount is less than 10%.(5)For different pesticides in the same substrate,cold storage and freezing treatment showed matrix weakening effect,but not significant;compared with heating and cold storage,heating treatment led to matrix strengthening effect of four pesticides in three types of substrates,and heating treatment at 70 ? had significant matrix strengthening effect on four pesticide residues in grapefruit substrate.Cellulase had obvious degradation effect on four organophosphorus pesticides in orange matrix,but had no effect on orange matrix and grapefruit matrix.