The health ministry and the city government of Osaka conducted hearings Saturday at the headquarters of Kobayashi Pharmaceutical over health hazards possibly linked to its supplement products containing beni kо̄ji red fermented rice.

They are believed to have looked into the company's operation structure and its response to the issue. The hearings finished after about two hours.

Of those who took the supplements, five people have died and 196 people have been hospitalized so far.

In a batch of the supplement product called Beni Koji Choleste Help, puberulic acid, a natural compound derived from blue mold, was detected. According to the ministry, puberulic acid is highly toxic and not normally contained in supplements.

Puberulic acid was detected in ingredients made in April to October last year, and those manufactured last September contained the highest amount of the toxic substance.

The National Institute of Health Sciences is rushing to analyze the ingredients in question and other samples provided by the company.

Kobayashi Pharmaceutical announced a voluntary recall of five beni kо̄ji-containing products, including the Beni Koji Choleste Help supplement, on March 22. As the move came about two months after the company learned of the health issue, there is criticism over its slow response.

Over the scandal, the ministry and the city government of Osaka conducted an on-site inspection of a Kobayashi Pharmaceutical plant in Osaka on March 30, based on the food sanitation law. The following day, the ministry and Wakayama Prefecture inspected a Kobayashi Pharmaceutical group plant in that western Japan prefecture.