Taiwan's former health chief Chiu Wen-ta speaks at a press conference over a tainted oil scandal in this Sept 5, 2014 file photo. [Photo/CFP]

TAIPEI - Taiwan's health chief Chiu Wen-ta resigned Friday night over a tainted oil scandal.

Chiu tendered his formal resignation to the island's administrative head Jiang Yi-huah hours after Pingtung prosecutors indicted key suspects.

He decided to step down since the investigation has been completed, Chiu said in a statement, extending his apologies to the public.  Chiu had offered to resign and take responsibility for the scandal before, but finally got Jiang's acceptance late last night, according to Sun Lih-chyun, spokesperson of Taiwan's administrative authority.

Prosecutors in Pingtung county on Friday indicted eight suspects on charges of fraud and breaches of food safety regulations.

Those charged included Kuo Lieh-cheng, owner of the illegal factory which made the oil, and Yeh Wen-hsiang, chairman of Chang Guann Co, which bought Kuo's product and processed it into lard.

Taiwan has been in the grip of fear and anger since Sept 4, when police busted Kuo's ring, selling hundreds of tonnes of cooking oil made from kitchen waste and grease from leather processing plants in Pingtung and neighboring Kaohsiung.

Yeh's Chang Guann, a well-established cooking oil supplier on the island, produced 782 tonnes of lard from the oil and sold it to hundreds of food companies and restaurants.

Over 1,000 businesses, including leading brands such as Wei Chuan, Vedan, Want Want and Master Kong, were identified as having used the oil.

Massive recalls of products ranging from cakes to instant noodles have been taking place over the last month, making this Taiwan's worst food scandal in recent years.

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