The yolk of eggs from a duck fed with Sudan IV-mixed feed, an illegal substance in China in this TV grab. On Sunday CCTV ran a report that claimed the red yolk duck eggs from Bai Yang Dian on the Beijing market were laid by ducks that had been fed Sudan IV, an industrial dye that may cause cancer in humans if eaten. Some farmers in Bai Yang Dian, Hebei province are using the dye to make red-yolk eggs in an attempt to attract customers. [CCTV photo]

Beijing has banned sales of some salted duck eggs suspected of containing a possibly carcinogenic red dye, the municipal authorities confirmed on Monday.

Officials have begun to seize stocks of red-yolk salted duck eggs for testing after some were suspected of containing the industrial dye, Sudan-IV.

"Sales of all red-yolk salted duck eggs from neighboring Hebei Province have been banned temporarily in markets, shopping malls and stores," said a spokeswoman surnamed Wang with the Beijing Administration of Industry and Commerce.

Test results would be published when the administration had finished collecting samples and conducting the tests, she said.

Red-yolk salted duck eggs are commonly thought to be more nutritious than yellow-yolk eggs and are usually more expensive.

Red-yolk duck eggs mixed with Sudan is still sold at a famers' market on November 13 in capital Beijing. The so-called red-yolk duck eggs from Baiyangdian was adulterated with Sudan which was eaten by ducks.[newsphoto]

The yolk of an egg (L) from a duck fed normally is compared with the yolk of one fed with Sudan IV-mixed feed, an illegal substance in China. On Sunday CCTV ran a report that claimed the red yolk duck eggs from Bai Yang Dian on the Beijing market were laid by ducks that had been fed Sudan IV, an industrial dye that may cause cancer in humans if eaten. Some farmers in Bai Yang Dian, Hebei province are using the dye to make red-yolk eggs in an attempt to attract customers. [CCTV photo]

Editor: Yan