Japanese health and other authorities have questioned officials at an Osaka-based pharmaceutical company, which is being investigated after supplements it makes were linked to several deaths and hundreds of hospitalizations.

Six officials from the health ministry and the Osaka municipal government interviewed officials at Kobayashi Pharmaceutical in Osaka on Saturday about their management practices.

Five people have died and 196 others have been hospitalized after taking supplements containing the company's "beni-koji" ingredient, which is produced from rice fermented with red yeast.

Authorities inspected the firm's factories a week earlier following reports that its "beni-koji" ingredient may be causing kidney problems.

The firm received the first report of suspected health damage in January. But it took more than two months before it went public with the news and began a voluntary recall for the products in question.