China vows overhaul of 'chaotic' milk industry

Part of the agency's cleanup effort was the deployment in mid-September of more than 5,000 inspectors to check dairy factories. Wang said the inspections covered all dairy producers across the country and would monitor the entire production process around the clock.

Chinese authorities believe suppliers trying to cut costs diluted milk, then added melamine to fool quality control tests and make the product appear rich in protein. Melamine, like protein, is high in nitrogen. However, the chemical can cause kidney stones as the body tries to eliminate it and, in extreme cases, can lead to life-threatening kidney failure.

Wang's watchdog agency said Sunday that tests showed that no melamine has been found in milk powder produced after Sept. 14, three days after a major dairy at the heart of the scandal recalled 700 tons of baby formula.

But the effects of the contamination continue to be felt, with 382 more children receiving treatment in Beijing's hospitals for kidney stones last week, according to the Beijing News, a state-run newspaper.

More than 3,000 children have been treated for kidney stones in Beijing since the scandal broke in early September, the paper said. Calls to the Health Ministry rang unanswered Monday.

The six suspects arrested Monday were being questioned in Hohhot, in northern China's Inner Mongolia region, a city spokeswoman said.

The arrests followed an investigation into two major Chinese milk companies based in Inner Mongolia, Xinhua said.

Recalls of Chinese-made products continued, with Iran's Health Ministry saying Sunday it would ban the import of all Chinese dairy products.

Japan ordered increased inspections of animal feed and pet food imported from China to make sure they don't contain melamine, Agriculture Ministry official Satoshi Motomura said Monday.

The order comes after Beijing said several Chinese feed makers allegedly mixed melamine into their products used for dairy cows.