Formaldehyde in Bombay-duck
Background
In view of the recent public concern over formaldehyde found in Bombay-duck (a kind of marine fish) in the Mainland, the Centre for Food Safety (CFS) has stepped up the surveillance of Bombay-duck in local markets for analysis of formaldehyde and other preservatives. Results show that there is no evidence of the use of formaldehyde in the samples tested.
Action Taken by the CFS
The CFS has sampled and tested six samples of Bombay-duck from the retail markets. According to the test results, preservatives were not detected in all samples. However, all the six samples contained formaldehyde at levels (37 to 130 mg/kg) compatible with natural occurrence. There is no evidence of use of formaldehyde in the samples.
What is Formaldehyde?
Formaldehyde is a chemical primarily for industrial use as a disinfectant and plastic manufacturing. The general population is exposed to formaldehyde via inhalation, ingestion and contact. Formaldehyde can be found naturally in food up to the levels of 300 to 400 mg/kg, including fruits and vegetables (e.g. pear, apple, green onion), meats, fish (e.g. Bombay-duck, cod fish), crustacean and dried mushroom etc (Appendix). Formaldehyde is water soluble and will be removed during cooking.
Ingestion of a small amount of formaldehyde is unlikely to cause any acute effect, but ingestion of large amounts of formaldehyde can cause severe abdominal pain, vomiting, coma, renal injury and possible death. The main health concern of formaldehyde is its cancer causing potential. The International Agency for Research on Cancer (IARC) considered that there was sufficient evidence for carcinogenicity in humans upon occupational exposure via inhalation, but there was no definitive evidence for exposure via ingestion.
Advice to Consumers
Choosing Bombay-duck
1. Buy the fish from reputable and reliable sources.
2. Only buy those fish that are properly refrigerated or displayed on ice.
3. Bombay-duck should smell fresh and mild, not chemical-like; look for those fish with shiny skin.
Preparing Bombay-duck
1. Put the fish in the refrigerator as soon as they are brought home.
2. Wash the fish thoroughly with running tap water.
3. Cook the fish thoroughly to an internal temperature of 750C or above. Consumers can check the flesh to see if it turns opaque and can be separated easily.
Advice to Trade
1. Traders are advised to be cautious about the origins from which they source their food products, and should only do so from credible sources.
2. Traders are reminded not to add formaldehyde into food.
3. Traders should maintain a proper cold chain to ensure that fish and fish products are kept safely throughout processes including storage, transportation and display for sale.
Further information
Further information about formaldehyde in food can be obtained from the following webpages:
Centre for Food Safety
21 December 2006