Speakers - AFHWC2025

Abstract

Tomato is a nutritious vegetable cultivated worldwide, consumed fresh in salads, cooked with meals and processed into various products. The use of pesticides in tomato farming for pest and disease control is common and can lead to the presence of pesticide residues in tomatoes sold in markets. This study aimed to determine the presence of residues on whole and skins of tomatoes sold in Nairobi and to identify whether single or multiple residues were present.   From January to June 2017, a total of 240 tomato samples were collected from open-air markets and supermarkets in Nairobi, Kenya. QuECHERS method followed by analysis using GCMS tandem LCMS/MS to detect pesticide residues from a panel of 98 were employed. About 14 residues were detected during the study; only 9.09% and 1.51% of samples were above EU and Codex MRLs respectively. Residues on skins (59 pesticides) were significantly more (p <0.05) compared to whole tomatoes (49 pesticides). The dry months of January, February and March had more pesticides (n= 6) above EU MRLs compared to wet months of April and May (n=1). Fenamiphos (0.19 mg/kg) and acephate (0.47 mg/kg) levels on the tomato skin were above EU MRLs whereas only dimethomorph (0.03 mg/kg) levels on whole tomatoes were above EU MRL. About 48.5% of all tomato samples had pesticide residues of which 27.27% were single and 21.21% multiple residues. Some single and multiple residues detected were above EU and Codex MRLs in dry months. Analysis of tomato skins revealed a higher concentration of residues compared to whole tomatoes. Some residues not detected in whole tomatoes were found in the skin, with some exceeding EU MRLs. These findings raise the potential health risks of consumers. Further surveillance should be conducted on fresh vegetables sold in urban areas to mitigate pesticide residues in local markets.