DEVELOPMENT OF MULTI-RESIDUE METHODS FOR PESTICIDE SCREENING IN ORGANIC FOOD SAMPLES

Summary

There is an ever-increasing demand for foods of local origin or cultivated using organic practices. However, the sector is becoming dominated by corporate players that might not strictly fulfill all the requirements of organic farming, with or without fraud intentions. This places an increased burden on certification bodies and traceability systems on which the authenticity of the organic products depends. Thus, to ensure the authenticity of foods marketed and labelled as organic, there is a need for robust, accurate and validated control methods. The objective of the AuthenticFood project is to combine novel analytical techniques to improve the reliability of organic authentication. In this framework, the present work describes the development of analytical methods for the determination of pesticides in food products.
The main challenge of this study was to reach the highest sensitivity allowing the detection of very low contaminations, especially for organic products, while keeping a wide range of target molecules. Hence, a priority list of pesticides has been established, based on scientific literature and reports from food agencies, with a special focus on organic foodstuff. On the basis of this list of target pesticides, three complementary analytical methods were developed using Triple-Quadrupole LC-MS/MS (positive and negative modes) and GC-MS/MS. In addition, an extraction protocol, based on the QuEChERS method, has been optimized considering the matrices and pesticides of interest. The final methods allow the detection of ca 150 pesticides at the ppt level and have been applied on a series of organic and conventional food samples.