The probe also found that samples of some imported distilled spirits contained a minute amount of DEHP, AQSIQ officials said.

But no domestic liquor brand covered by the probe has been found to deliberately add plasticizers to their products, the official confirmed.

The taint mainly came from plastic containers, pipes, sealing materials and packages used during production, storage and transport, as well as the environment, the official said, citing analysis given by industry experts.

As distilled spirits must be clear and transparent, there is no need for producers to add DEHP, which is used for thickening and emulsification, the official said.

MOH has blacklisted DEHP, high doses of which can lead to testicular or kidney damage and fertility problems, as an inedible material that is likely to be illegally added to food last year.

DEHP, though banned from being directly added to food products in China, can be widely detected in the environment due to its common use in plastic products, the MOH official said.

Currently, neither the Codex Alimentarius Commission nor any country has set a limit standard on the amount of DEHP found in spirits, the official said.

But estimates made by the China National Center for Food Safety Risk Assessment show that consuming 0.5 kg of the defective Jiugui Liquor products each day will not have an effect on health, the official said.

The AQSIQ official said the government has ordered local quality authorities to expand checks to spirit makers nationwide.

Producers have also been urged to determine the cause of the problem and take necessary measures, such as improving processing equipment and changing packing materials, to correct it, the official said.

The scandal of plasticizers in food was first exposed in Taiwan. In May 2011, the island's health authorities detected toxic plasticizers in food additives used in the production of soft drinks, tea drinks and dietary supplements. Nearly 1,000 products and 300 companies were involved.

Some experts said the toxicity of plasticizers was much more serious than melamine, a chemical raw material which can lead to reproductive damage or bladder or kidney stones.

A 2008 scandal in which milk was laced with melamine led to the deaths of at least six babies and sickened 300,000 others in the Chinese mainland.