Presence of selected organophosphorus pesticide residues in raw cucumber and tomato samples in Taman Universiti, Johor

Abstract

Consumption of raw vegetables is common among Malaysians due to its nutritional values as well as anecdotal evidence supporting its medicinal properties. Although periodical analyses of pesticide residues on imported vegetables have been performed by the relevant authority, the same has not been amply emphasized on the locally produced vegetables and those that are available at food outlets, rendering the possible threat towards human health. In this research, the possible presence of diazinon, chlorpyrifos and dimethoate residues in two commonly eaten raw vegetables viz. cucumber and tomato conveniently sampled from four food outlets within Taman Universiti was investigated using gas chromatography with electron capture detector (GC-ECD) preceded by the Jabatan Kimia Malaysia-validated liquid-liquid extraction method (JKM F0702). Samples of organic cucumber and tomato were used as controls. Once detected, the confirmation was done using gas chromatography with mass spectrometer (GC-MS). Results of this research revealed that presence of diazinon, chlorpyrifos and dimethoate residues were not detected in all the samples of cucumber and tomato sampled from the selected permanent food outlets. The fact that two unknown compounds were found in both of the organic cucumber and tomato samples eluted at 2.25 minutes and 3.58 minutes, respectively, while an unknown compound eluted at 3.47 minutes was evident in one of the tomato samples included in this research, expanding the spectrum of pesticide residues in these vegetables for future studies deserves consideration. Although the concentrations of diazinon, chlorpyrifos and dimethoate found in those vegetables appear to be within the acceptable levels for human consumption, absence of possible health threats for human may not be construed, considering the limited samples and organophosphorus pesticide residues included in this research.