Red-yolk salted duck eggs on sale in Beijing have been found to contain Sudan B, a carcinogenic red dye, the municipal health authorities announced on Tuesday.

Tests showed that the amount of Sudan Red B in six of the 22 samples ranged from 0.041 to 7.18 parts per million (ppm), the bureau reported.

Five samples originated from food processing enterprises in Baiyangdian district, Zhuozhou city and Anxin county in north China's Hebei province and the other one came from a Jingzhou-based enterprise in central China's Hubei province.

The producers are believed to have added the red dye to the feed for ducks that lay yellow-yolk eggs in order to pass them off as the more expensive and nutritious red-yolk variety.

Beijng officials have begun investigations into the six manufacturers and have ordered the recall and destruction of the eggs. It has so far seized 1,159 kilograms of the red-yolk eggs.

Three enterprise managers in Hebei province have been arrested by the police for adding Sudan Red IV, an isomer of Sudan B, to the feed, according to the provincial Food and Drug Administration.

Beijing has banned the sale of red-yolk eggs made by the six manufacturers and buyers of these eggs can return the products, said the municipal bureau.

Both Sudan Red series are banned from being used in food in China and many other countries as they increase the risk of cancer.

Source: Xinhua