Industrial bleach was discovered in Deshengda Glass Noodles, made in  Yantai, Shandong Province. [File Photo: Sohu]

Some Shanghai markets are still selling glass noodles banned in Beijing because they may be carcinogenic.

All glass noodles produced by a Shandong Province company were seized by Beijing authorities on Wednesday after they were found to contain an industrial bleach, which is an illegal food additive in China.

The Shanghai Food and Drug Administration is on the case and will carry out random checks on noodle retailers.

"We haven't found any problem with glass noodles in local markets in regular inspections," said Jin Huichun, a SFDA official.

The Beijing Food Safety Office ordered all markets on Wednesday to suspend the sales of the glass noodles produced by Deshengda Glass Noodles Co in Yantai, Shandong Province.

Sodium formaldehyde sulfoxylate was found in the noodles. The bleach has been found to damage the liver and kidneys, and may even cause cancer, said a report released by the office.

The bleach makes the glass noodles more springy and transparent.

Shanghai Daily found the glass noodles banned in the capital on the shelves of the French-owned Auchan Hypermarket Changyang branch in Yangpu District. The hypermarket was not available for comment.

Glass noodles made in Longkou, an area of Yantai, are famous for their springy quality, which makes them popular with Chinese families.

The noodles can be cooked with vegetables to make soups or mixed with seasonings to create salads.

Two years ago, six glass noodle manufacturers in Longkou were found using corn starch instead of bean starch in their noodles in a cost-cutting ploy. After that, Yantai authorities suspended all production of glass noodles for two weeks.