Taiwan's food safety watchdog has landed a heavy blow on the cooking oil industry, with prosecutors charging top executives at four major food companies — bad news for the firms and unsettling for consumers.

• Soybean salad oil from Chung Lien tested over the legal limit for benzopyrene, a known cancer-causing chemical.
• Taichung prosecutors charged 15 people plus four companies — Chung Lien, Formosa Oilseed (Fwusow), Fu Mao Oil and Taisun — with breaking food safety law.
• Those charged include the chairmen and general managers of the companies, not just line staff.
• Both Chung Lien and Fwusow declined to comment on the charges.

Outlook: The case now moves to court, and more scrutiny of Taiwan's edible oil supply chain is likely in the coming months.