China's top quality watchdog said they hadn't found any Taiwan food products containing tainted oil on the mainland market, but some insiders warn that tainted food might still be purchased online, according to the National Business Daily.

On Taobao, China's largest online shopping platform, imported food products of some of the affected companies are still on sale.

Taiwan police last Thursday busted a ring of six people selling recycled cooking oil made from kitchen waste and grease from leather processing plants. They found Chang Guann Co., a well-established cooking oil supplier, had purchased recycled oil to produce lard, most of which was sold to nearly a thousand food companies and restaurants, including a number of leading brands.

The news not only angered Taiwan's consumers, but has also raised concern on the mainland. China's General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ) ordered local authorities to suspend inspection applications filed by the affected companies and restaurants, and to carefully examine their past export records.

Several of the food companies involved said the recycled lard could not be in their products produced on the mainland.

The Beijing News reported that Taiwan-based food companies including Wei Chuan, 85℃, Maxim, Sheng Hsiang Jen, and Haw Di-I have announced that their branches on the mainland didn't buy any oil products from Chang Guann.

The scandal has also affected neighboring Hong Kong and Macao.

Chang Chuann may be fined up to 88 million NT dollars ($2.9 million dollars ) for the oil scandal.