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.

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