Title: DETERMINATION OF PROPOSED MAXIMUM RESIDUE LIMIT OF DELTAMETHRIN IN BLACK PEPPER (PIPER NIGRUM L.)
Abstract: Residue trials of deltamethrin in black pepper (Piper nigrum) were conducted to estimate the maximum residue limit (MRL). Five residue trials were conducted at three commercial growers’ plots in Johor, Perak and Sarawak (Malaysia). The study plots contained 120 mature pepper vines which were selected and treated with deltamethrin using the manufacturer’s recommended rate (0.01 kg a.i./ha). The insecticide was applied with a motorized sprayer on monthly intervals. Green pepper berries samples (500g) were randomly collected from the plots at 1, 3, 5 and/or 7 days after the last spray. Analytical procedure of deltamethrin extraction was validated prior to actual analysis. Satisfactory recoveries ranging from 86.2% to 110.2% were obtained for the fortified pepper berries samples. The limits of detection and limits of quantification for deltamethrin were 0.521 μg kg−1 and 1.63 μg kg−1, respectively. Results showed that deltamethrin residues were at the low level with the residue value ranging between <0.08 mg/kg to 0.032 mg/kg. Dissipation of deltamethrin in black pepper berries followed first-order kinetics, and the mean half-lives was 3.2 days after the last treatment. The results also indicated that pepper berries could be safely consumed after 5 days of application. The determined value of proposed MRL for deltamethrin was 0.5 mg/kg. The Dietary Intake Assessment based on Malaysian Food Consumption Pattern confirmed that the proposed MRL concentration will not cause health risks to consumers. Results obtained also showed that all the pesticide residue were stable at -20oC and did not show any significant decrease or increase in the pesticide levels with the degradation percentage of 2.6% indicated that this was the recommended temperature for long term storage.