Three leading dairy companies have been removed from China's Famous Brands list after their milk was found to be contaminated with melamine, the General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ) said on Friday.

"In order to preserve the reputation of China's Famous Brands, the AQSIQ decided to revoke the titles given to Yili and Mengniu groups (both based in the Inner Mongolia autonomous region), and Shanghai-based Bright Diary," the agency said.

Tests conducted on milk over the past few days showed 24 - all from the mentioned firms - of 1,202 batches were contaminated, the agency said on Thursday.

The AQSIQ has asked the three companies to recall all their contaminated products.

Eleven of the 121 Mengniu batches that were tested contained melamine, a chemical that makes milk appear rich in protein during quality tests, but can also cause kidney problems.

Melamine is used frequently to make products including plates, bowls and mugs, but is strictly banned in the food industry.

The highest concentration of melamine was found in samples from Bright Diary - six of its 81 batches were contaminated.

Every kilogram of its liquid milk contained 8.6 mg of the chemical.

Seven of the 81 Yili batches tested contained melamine.

The three firms' milk powder products also tested positive for melamine, and they have begun recalling them.

"Yili group had already recalled all of its contaminated milk powder products in the shortest period of time," Yili said in a proclamation.

The other two promised a similar action in their so-called "Earnest Proclamations".

On Friday, the National Development and Reform Commission required price administration bodies nationwide to closely watch local markets to prevent price hikes on milk powder products.

The notice came out two days after the Shanghai Evening Post reported the prices of imported milk powder products might rise.

But four major foreign milk exporters to the Chinese market all promised they would not raise their prices.

"It is not proper to raise the price during this special period of time," US milk powder manufacturer Wyeth was quoted as saying by Jiangsu-based Yangtze Evening Post.

A total of 6,244 infants nationwide who were fed contaminated milk products produced by Sanlu Group have been diagnosed with various urinary tract problems, including kidney stones, according to the latest update published on Thursday. Four babies have died.

(China Daily September 20, 2008)