TOKYO - JAPANESE police on Wednesday raided a wholesaler that redistributed rice tainted by pesticide, in a scandal that has set off nationwide worries over food safety.

Dozens of police officers entered factories and offices across Japan of Osaka-based Mikasa Foods, whose top executives admitted selling industry-use grains as edible rice.

They also searched houses of Mikasa executives in front of journalists and photographers, television footage showed.

Mikasa bought the tainted rice from the government for industrial use, such as making glue, but resold it as edible rice to make a profit.

The tainted rice has found its way into meals at hospitals and nursing homes, as well as into popular liquor and confectionery.

Authorities should carry out a thorough investigation, said chief government spokesman Nobutaka Machimura, who stepped down on Wednesday as a new prime minister took over.

'The government has already sent the case to prosecutors. We must get to the bottom of this by thoroughly investigating it and backing up the case with evidence,' he told his final news conference.

The government must also set up a framework to prevent similar incidents, he added.

The tainted grain was part of rice imported by the Japanese government from China, Vietnam and other countries under its international commitment to open its rice market.

The farm minister quit last week for failing to detect the shipments into the food system, which came to light only after a whistle-blower in the company came forward.

Concern was already high in Japan over food safety after 10 people needed hospital care for eating Chinese-made dumplings laced with pesticide. -- AFP