Test No 506: Stability of Pesticide Residues in Stored Commodities

         The aim of these studies is to demonstrate the time period for which stability has been shown in representative commodities from crops.          Freezer storage stability studies should include sufficient starting material and should have a sufficiently high concentration of residue to allow for any observed decline during storage to be quantified. Samples could either be from crops (or animals) that have been treated with pesticides in the field, or from the spiking of control commodities with known amounts of each component of the residue definitions. Freshly spiked control samples of the stored commodities should be analysed at each of the time points when aged/stored commodities are removed from frozen storage for analysis. The control samples used for procedural recovery determinations will be the same commodity. At least two sampling intervals (time zero and other) should be used the sampling interval depends on the stability of the residues. Duplicate samples of every commodity at each time point for all components of the residue definitions need to be analysed. The report should include the residue results and the statistical treatments. 