Effects of simulated processing on pesticide residues in spinach and its dietary exposure assessment

The effect of processing of spinach sprayed pesticides in field,processing stimulated in lab and detection by GC on the residues of chlorpyrifos,cypermethrin and fenvalerate and its dietary exposure assessment in spinach were studied.The results showed that washing and blanching step could reduce 22.6%,53.8% and 50.8%,respectively for the pesticides mentioned above with recommended dose used in field(which was 0.0388 g/m2 for chlorpyrifos,0.001 g/m2 for cpermethrin and 0.01 g/m2 for fenvalerate),and with double dose which was 8.5%,61.4% and 40.2%,respectively.The air dry step could eliminate the residue above 50% for chlorpyrifos,however,about 10% for cypermethrin and fenvalerate.The dietary exposure assessment was carried out for the residue in the fresh spinach and the dry spinach,respectively,and the processing factor could reduce the dietary intake with the range from 62.1% to 76.7%.The conclusion is that the loss of pesticide is less affected by washing and blanching,and more affected by dry for chlorpyrifos,however it is on the contrary for cypermethrin and fenvalerate.The dietary intake assessed with processing factor would be greatly reduced,near to the real intake.