Food safety is once again in the limelight following media reports that a "significant portion" of used cooking oil from Taiwan was being recycled and returned to people's dining tables.

Taiwan has ordered the cooking oil supplier at the centre of the food scandal to pull all of its "Chuan Tung" lard oil products from store shelves, even product that passes food safety tests.

Taiwan's Food and Drug Administration released test results showing that one sample of the oil sold under the Chuan Tung brand met requirements.

But samples from two other batches¹ - obtained by prosecutors² investigating the scandal - failed.

The FDA also says there is no record of Chang Guann importing gutter³ oil from the mainland.

Officials say recycled oil has been supplied to more than 900 restaurants and bakeries.

China's top quality watchdog has warned consumers on the mainland to be on the lookout⁴ for products which may have been exported by companies involved.

Kuo Lieh-chen, the owner of an illegal factory at the center of the scandal, has been in custody⁵ since Saturday.

Investigators⁶ found that Chang Guann bought 243 tons of tainted⁷ oil from Kuo and mixed it with lard oil, selling that product to 235 customers across the island.

Buyers include leading food companies Wei Chuan Foods Corp, Taiwan Sugar Corp, and Gourmet⁸ Master Co, which owns the bakery and coffee chain 85°C.