Japan's health ministry says it will ask about 200 companies to conduct self-inspections in response to growing concerns about health supplements containing "beni-koji." That is rice fermented with red yeast.

The Kobayashi Pharmaceutical products are reportedly linked to four deaths and dozens of hospitalizations.

A panel of experts convened by the ministry met Thursday and recommended the measure.

The government says it will ask companies that received Kobayashi's "beni-koji" material to conduct self-inspections.

Japanese Chief Cabinet Secretary Hayashi Yoshimasa said earlier that the government will work to ensure food safety.

He said: "We've provided information to the World Health Organization and foreign governments. We'll keep doing so in an appropriate and timely manner to maintain public trust in Japanese food products."

Kobayashi Pharmaceutical held a shareholders' meeting behind closed doors on the same day. Its president apologized and said the firm will investigate the cause.

One shareholder said, "It's a problem that the company is causing people so much trouble."

Another shareholder said, " I hope the cause of this will be discovered soon and that the many people taking the company's other products feel safe."

"Beni-koji" is taken in pill form by people wanting to lower their cholesterol, or for other health reasons.

The company says some manufactured between last April through December could contain an "unintended substance." It says that substance could be the cause.

The company says more than 90 people who consumed the products were hospitalized after developing kidney problems.

Nihon University School of Medicine Professor Abe Masanori examined three of those patients from November last year to last month.

He said none of them had chronic disease before they started ingesting Kobayashi Pharmaceutical's "Benikoji CholesteHelp" around last spring.

He added, "In one case, if the patient had not been undergoing regular blood and urine tests, her condition could have advanced to a point where it was detected only when it was terminal.

Abe says he was concerned about the product and contacted Kobayashi Pharmaceutical last month, explaining the patients' symptoms in detail.