TOKYO — Two top executives at Japanese drugmaker Kobayashi Pharmaceutical are stepping down as an investigation continues into 80 deaths that could be linked to some of its products.

The company says president Akihiro Kobayashi and chairman Kazumasa Kobayashi, both members of the firm's founding family, have resigned.

The decision was made "to clarify executive responsibility" over the issue involving its beni kōji fermented rice products, Kobayashi Pharmaceutical said.

In March, the company recalled five of its products, saying it had received reports of kidney problems from customers.

The company began an investigation after a doctor alerted them to reported health problems in January. It also opened a hotline for customers seeking advice.

Affected customers reported symptoms such as changes in the color of their urine, swelling in their limbs and fatigue.

Kobayashi Pharmaceutical later said it had found a potentially toxic acid produced by the mold at one of its factories.

Separately, the company's board of directors said it would "pray for those who died and offer condolences to the bereaved families."

"We would also like to once again deeply apologize to our customers and business partners," the statement added.

The company's head of sustainability policy Satoshi Yamane will be its new president.

Akihiro Kobayashi, who has said he wants to take responsibility for any harm done to customers, will remain at the company to deal with any compensation arrangements.

Beni kōji is rice fermented with monascus purpureus, a species of reddish-purple mold. While advertised as a health supplement for high cholesterol and blood pressure, it is also widely used as a traditional dye for food products. — BBC