The Chinese mainland's top quality watchdog put out a warning on Saturday about food products from Taiwan that contained recycled cooking oil.

The authority has closely followed the issue and contacted authorities in Taiwan to get more information about exported oil products and a list of companies in the mainland that could be affected, the General Administration of Quality Supervision, Inspection and Quarantine said in a statement on Saturday.

On Thursday, police in Taiwan arrested six people involved in selling hundreds of tons of recycled cooking oil made from kitchen waste and grease from leather processing plants in Kaohsiung and neighboring Pingtung, Xinhua News Agency reported.