Two Taiwanese businessmen have been charged with using banned industrial dyes to adulterate food products, a case which prompted mass recalls in the island’s latest food safety scandal, prosecutors said Tuesday.

They sought a 20-year jail term for Lu Tien-jung on charges of food safety violations and fraud. His son and business partner Lu Chia-chien may face an 18-year jail term on the same charges, in addition to a fine of Tw$20 million (S$882,600) for each man.

The pair, who run the Chien Hsin company at the centre of the scandal, were charged with manufacturing and selling soybean emulsifiers tainted with dimethyl yellow and diethyl yellow dyes which have been banned from food products since late 2008, said the Changhua district prosecutor’s office.

Meanwhile, the President of Taiwan, Ma Ying-jeou, on Tuesday filed defamation lawsuits against a radio host for alleging that he accepted illicit political donations from a company implicated in food safety scandals.

Ma is seeking compensation of NT$10 million (HK$2.4 million) and printed apologies in four major newspapers from Clara Chou in a civil defamation suit, his lawyer Hung Wen-jun told reporters outside Taipei district court.

He also filed a criminal aggravated defamation suit against Chou since she “continues to make the same remarks concerning the case even though relevant persons have made many clarifications or even filed lawsuits against her”, Hung said.

Chou accused Ma of accepting under-the-table funds totalling NT$200 million to act as the “guardian” of food giant Ting Hsin, which has faced widespread public outrage and an island-wide boycott of its products following several food safety scandals.