Acute organophosphorus food poisoning caused by contaminated green leafy vegetables

An outbreak of food poisoning in which 105 persons from various parts of Singapore were affected was traced to one type of green leafy vegetable (Brassica alboglabra) that had been imported. The clinical symptoms were generally mild and the incubation period short (median 2.5 h). The etiology was confirmed when excessive levels of two organophosphorus pesticides--methamidophos (Tamaron/Monitor; 2.4 ppm-31.7 ppm) and profenofos (Selecron/Curacron; 1.1 ppm-5.4 ppm) were detected in the implicated food, and blood cholinesterase levels of the hospitalized patients were depressed by 26.1%-81.4% based on the lower limit of the reference range. All consignments of the implicated vegetables were immediately sealed and destroyed. Monitoring of imported vegetables for excessive pesticide residues has been enhanced.