Food Safety Focus (5th Issue, December 2006) – Food Incident Highlight

Nitrofurans Residues Found in Marine Fish

In November 2006, the Centre for Food Safety (CFS) stepped up surveillance on turbot found in local markets with regard to veterinary drug residues. Out of a total of five samples of turbot tested, all samples were found to contain nitrofurans whereas two samples were detected with malachite green.

In view of public concern over live fish as a whole available for sale in Hong Kong , the CFS further collected samples of a variety of marine fishes for analysis of veterinary drug residues in early December 2006. A total of 20 samples were examined; all the samples were free from malachite green. However, nitrofurans were detected in three samples (including pompano, flowery grouper and tiger grouper).

Nitrofurans are a family of chemical compounds which have broad-spectrum antimicrobial activities and can be used in both humans as well as animals including fish. Overseas studies showed that nitrofurans had been used in pigs, poultry, shrimps and fish. The main concern over nitrofurans in food is the carcinogenicity of these compounds and the lack of information regarding the safety of their metabolites. Although there is evidence suggesting that nitrofurans might cause cancer in animals, there is inadequate evidence that it can cause cancer in humans. Nitrofurans have been prohibited for use in food-producing animals in many countries including the members of the European Union, United States , Canada , Australia and Mainland China .

Based on present information regarding the levels of nitrofurans residues found in the affected marine fish samples, risk to health is low upon usual consumption of the fish. There is no cause for undue alarm. The public is advised to maintain a balanced diet.