A survey of 85 vegetable samples from 12 hotpot/shabu restaurants and five Bangkok markets produced several positive screening-test signals for organophosphates, carbamates or pyrethroids. Confirmatory LC-MS/MS detected no residues above the detection limit in positive samples. The sampled set therefore showed low confirmed risk, but this does not prove that all Bangkok vegetables are residue-free.
Key findings
- GT screening flagged organophosphate/carbamate signals at levels classified as safe in four restaurant samples (6.67%) and two market samples (8.00%). PY screening flagged eight restaurant samples (13.33%) as safe-level and four (6.67%) as unsafe-level, with one positive in a type-1 market. Chinese cabbage and carrot were most frequently flagged. Confirmatory LC-MS/MS found no target residues above the LOD, and post-boiling screens were negative.
Why this matters globally
The study is relevant to urban food surveillance in a rapidly growing restaurant sector. Rapid kits can triage samples but should not determine final safety. Confirmatory analytics help avoid both false alarms and unjustified reassurance.
Thai researcher contribution
Mahidol University researchers designed a Bangkok-specific consumption study and linked field screening with confirmatory laboratory analysis, directly addressing a Thai urban food-safety question.
Limitations to consider
Eighty-five samples from limited sites and one period cannot represent all Bangkok supply chains or seasons. LC-MS/MS covered specified compounds and limits; below-LOD does not mean absence of every pesticide. Attributing low confirmed residues to sanitation policy is interpretive because no before-after or control-area design was used.