Removal of Methamidophos and Carbofuran Residue in Broccoli during Freezing Processing

CHIA-FEN TSAI¹*, SHIN-SHOU CHOU¹ AND YUAN-TAY SHYU²

1. National Laboratories of Foods and Drugs, Department of Health, Executive Yuan, Nankang, Taipei 115, ROC

2. Graduate Institute of Horticulture, National Taiwan University, Taipei, Taiwan , ROC

Broccoli harvested 10 days after being sprayed with 50% methamidophos (0.8 and 1.2 l/ha) and 3% carbofuran (40 and 60 kg/ha) was used to study the extent to which pesticide residues could be removed by freezing processing. Results indicated that a 3-min washing process can remove 44.1 and 32.8% of the high and low doses of sprayed methamidophos, and 33.7 and 34.3% of the high and low doses of sprayed carbofuran, respectively. Blanching in 2% brine at 95℃for 3 min removed 99.3-100% methamidophos and 95.6-96.2% carbofuran and ensured acceptable and satisfactory broccoli quality. During five months of frozen storage, 50% of the methamidophos and almost none of the carbofuran degraded in the thawed samples.