The public has been on its guard about buying food, especially types containing edible gelatin, ever since media outlets reported this month that drug capsules contaminated with chromium had been discovered.

The State Food and Drug Administration said on its website on Friday that 15 companies in Zhejiang, Henan, Sichuan and Chongqing were found to be producing the capsules.

The administration plans to order local drug authorities to supervise the recall and destruction of the tainted products.

The production licenses of companies engaged in illegal activities will be revoked, and people who are suspected of committing criminal offenses may be subject to legal charges, it said.

The administration has asked makers of drug capsules and pharmaceutical companies that produce capsule medicines to inform the public of the ingredients used in their products.

In a statement issued on Sunday, the Ministry of Public Security said inspections conducted over a week in Zhejiang, Hebei and Jiangxi provinces had led to 80 illegal production lines being shut down.

By Sunday, police had detained 45 people, arrested nine and seized more than 77 million capsules tainted with chromium.

Nine pharmaceutical companies have been accused of manufacturing drug capsules that contain inedible industrial gelatin. Moreover, 13 commonly prescribed drugs were found to be made at times with industrial gelatin, which contains a much greater amount of chromium than edible gelatin.

With stricter food standards in force, tainted capsules have been discarded in Xinzheng, Henan province, and Xi'an, Shaanxi province, media reported.

The State Food and Drug Administration said on its website on April 23 that local drug authorities should take strict measures to stop pharmaceutical companies from improperly discarding toxic capsules and to ensure that all such products are destroyed once they are detected.

Sun Zhongshi, an expert with the Ministry of Health's national rational drug use monitoring system, said the scandal is a sign that the drug watchdog should strengthen its supervision of the substances found both inside and outside capsules.

A group of lawyers have formed a team to take legal action against pharmaceutical companies that have misused industrial gelatin.

On April 23, they released a statement online saying they can help the victims in the scandal protect their rights.