Determination and Safety Assessment of Imidacloprid Residues in the Fruit Bodies of Three Mushroom Species

Residual levels of imidacloprid after application of different concentrations of the insecticide to fruit bodies of Lentinula edodes,Pleurotus ostreatus and Agaricus bisporus were determined by liquid chromatography.Recovery rates ranged between 84%-93% and the limit of detection(LOD) was 0.01 mg/kg.Disappearance of imidacloprid from fruit body tissue followed first-order kinetics and the half-life of the insecticide in L.edodes,P.ostreatus and A.bisporus fruit bodies was 3.6 d,3.5 d and 2.3 d,respectively.Our data indicated that imidacloprid application should be controlled at a rate of 10-30 g active ingredient(a.i)/square hectare,1-2 times during a cultivation cycle,with a pre-harvest interval of not less than 3 d.Based on dietary risk quotient assessments,it is recommended that maximum imidacloprid residue levels(MRLs) in the mushroom fruit bodies should not exceed 1.0 mg/kg.