More red-yolk duck eggs containing the carcinogenic red dye Sudan Red IV have been found in some provinces and cities including Beijing, according to local food security office Monday.

The eggs were found to have been produced by Sanhu Eggs Co. Ltd, based in East China's Jiangsu Province, sparking fears that the cancer-causing dye is in wider use than first thought.

Last week, 1,159 kilograms of red-yolk eggs, all produced in neighboring Hebei Province, were seized in the capital and the sale of the eggs from the province was banned.

The news comes on the heels of reports that the dye has also been detected in over 6,000 chicken eggs on sale in two Metro and Carrefour supermarkets in Southeast China's Fujian Province. The provincial administration of quality supervision said the harmful substance was as high as 0.3 milligrams per kilogram.

The eggs, which have been taken off shelves, were produced by the Shendan Health Food Co. Ltd. in the central province of Hubei. The dye has also been found in red-yolk salted duck eggs in Zhejiang.

Last year, the Ministry of Agriculture reiterated the ban on production, sale and use of Sudan dyes in food, after it was found in some brands of pepper sauce, chilli oil and KFC's New Orleans roast chicken wings.

However, some food producers have continued to feed hens and ducks with the dyes to turn egg yolks into the more expensive red variety.

The General Administration of Quality Supervision, Inspection and Quarantine has called on local offices and authorities to step up routine inspection and ordered relevant firms to stop production and sales.

The case is the latest in a series of food safety problems. Recent cases include parasite-infested snails in Beijing, steroid-tainted pork and turbots that contain excessive amounts of carcinogens in east China.

(Xinhua News Agency November 20, 2006)