title: Food safety in Thailand 2: Pesticide residues found in Chinese kale (Brassica oleracea), a commonly consumed vegetable in Asian countries.
abstract: There is increasing public concern over human health risks associated with extensive use of pesticides in agriculture. Regulation of pesticide maximum residue limits (MRLs) in food commodities is established in many developed countries. For Thailand, this regulation exists in law but is not fully enforced. Therefore, pesticide residues in vegetables and fruits have not been well monitored. This study investigated the pesticide residues in Chinese kale, a commonly eaten vegetable among Asians. The Chinese kale samples (N = 117) were purchased from markets in Nakhon Pathom Province, Thailand, and analyzed for the content of 28 pesticides. Analysis was performed by the multiresidual extraction followed by GC-MS/MS. Of pesticides investigated, 12 pesticides were detected in 85% of the Chinese kale samples. Although carbaryl, deltamethrin, diazinon, fenvalerate and malathion were found in some samples, their levels were lower than their MRLs. However, in 34 samples tested, either carbofuran, chlorpyrifos, chlorothalonil, cypermethrin, dimethoate, metalaxyl or profenofos was detected exceeding their MRLs. This represents a 29% rate of pesticide detection above the MRL; a rate much higher than in developed countries. Washing vegetables under running water significantly reduced (p < 0.05) profenofos residues by 55%. The running water method did not significantly decrease cypermethrin residues in the samples but washing with vinegar did. Our research suggests that routine monitoring of pesticide residues is necessary to reduce the public health risks associated with eating contaminated vegetables. Washing vegetables before consumption is advisable as this helps to reduce the level of pesticide residues in our daily intake.
authors.affiliation: Center for Innovation Development and Technology Transfer, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand. Electronic address: sompon-999@hotmail.com.
authors.forename: Sompon
authors.initials: S
authors.lastname: Wanwimolruk
authors.affiliation: Center for Innovation Development and Technology Transfer, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand.
authors.forename: Onnicha
authors.initials: O
authors.lastname: Kanchanamayoon
authors.affiliation: Center for Innovation Development and Technology Transfer, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand; Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand.
authors.forename: Kamonrat
authors.initials: K
authors.lastname: Phopin
authors.affiliation: Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand.
authors.forename: Virapong
authors.initials: V
authors.lastname: Prachayasittikul
mesh_terms: D001937:Brassica / Q000737:chemistry*; D004781:Environmental Exposure / Q000032:analysis* / Q000706:statistics & numerical data; D005506:Food Contamination / Q000032:analysis* / Q000706:statistics & numerical data; D006801:Humans; D010573:Pesticide Residues / Q000032:analysis*; D010575:Pesticides / Q000032:analysis; D013785:Thailand
chemical_list: D010573:Pesticide Residues; D010575:Pesticides
keywords: Chinese kale; Food safety; Pesticide residues; Pesticides; Vegetable