Jul 2, 2007 6:58 PM

The Food and Drug Administration (FDA) has increased import control of all farm-raised catfish, basa, shrimp, dace (related to carp), and eel from China. The agency will detain these products at the border until shipments are shown to be free of residues from drugs not approved by the United States. No reports of illnesses have occurred so far.

In sampling from October 2006 through May 2007, FDA repeatedly found that farm-raised seafood imported from China were contaminated with antimicrobial agents.

These contaminants were the antimicrobials nitrofuran, malachite green, gentian violet, and fluoroquinolone. Nitrofuran, malachite green, and gentian violet have been demonstrated to be carcinogenic with long-term exposure in lab animals. Use of fluoroquinolones in food animals may heighten resistance to antibiotics.

Levels of the drug residues detected are mostly at or near the minimum level. FDA is not going to recall products already in the United States and is not advising consumers to destroy or return imported farm-raised seafood already acquired.