Following health concerns flamed by supplements with red yeast rice, known as "beni-koji," manufactured by Japan's Kobayashi Pharmaceutical, Japan's health ministry and local authorities on Sunday conducted on-site inspections at the company's factory in the western Japanese prefecture of Wakayama.

The inspection, carried out under the Food Sanitation Act, was jointly conducted by the Ministry of Health, Labour and Welfare (MHLW) and Wakayama prefectural government to investigate the root cause behind the reported health issues.

As of Friday, the Osaka-based pharmaceutical's red yeast rice dietary supplement has been associated with five deaths and over 100 hospitalizations, with nearly 700 others seeking medical advice or planning to do so.

The product in question is called Beni-koji Choleste Help, a type of granules advertised with the effect of lowering LDL cholesterol levels, and was manufactured at Kobayashi Pharmaceutical's Osaka factory, which shut down in December 2023.

The Wakayama factory in Kinokawa City, where equipment from the Osaka factory was relocated after its closure in December 2023, was involved in the production of raw materials for the supplements.

This inspection marks the second consecutive day of inspections by the MHLW following their visit to the Osaka factory on Saturday.

An unintended component called "puberulic acid," derived from blue mold, has been detected in the company's product, according to the MHLW and the company.

The substance is a potent antibacterial and antimalarial agent that can be toxic, but the extent to which its ingestion may pose health risks or cause kidney damage remains unclear, according to the ministry.

The company rolled out Choleste Help in February 2021, selling around 1 million packages by the end of February this year.

Widening health problems have intensified criticism of Kobayashi Pharmaceutical's sluggish response, as it took the company about two months from receiving health damage reports to the announcement of voluntary recalls.

The voluntary recall of products containing Kobayashi Pharmaceutical's beni-koji as a food ingredient has now expanded nationwide, affecting various products including sake, confectionery, bread and miso.

Earlier reports showed that the company had supplied the rice fermented with red yeast to 52 manufacturers.