The number of Chinese infants sick in hospital after drinking tainted milk formula doubled to nearly 13,000 and Premier Wen Jiabao threatened harsh punishment for culprits in the latest blight on the "made-in-China" brand.
Four deaths have been blamed on the toxic milk powder causing kidney stones and agonising complications, and a string of Asian countries have banned or recalled Chinese milk products.
The Health Ministry said the number of children hospitalised due to milk powder contaminated with the industrial chemical melamine had risen from a previously announced total of 6,244 -- which included many who had left hospital -- to 12,892, including 104 in a serious condition.
More than 1,500 had already left hospital and nearly 40,000 with milder symptoms "received clinical treatment and advice" before going home.
The jump to more than 54,000 affected children was announced late on Sunday, escalating the scandal that has again shaken trust in Chinese products following last year's scares over toxic and shoddy goods ranging from toothpaste and drugs to pet food and toys.
Melamine has also been found in cartons of milk and some dairy exports, but no illnesses from those sources have been reported.
Wen visited hospitals in the national capital in a bid to reassure an anxious public that the government was acting.
"The public is worried, doctors are worried, and we're also worried," he told parents and staff, according to the state-run Xinhua news agency.
"The most crucial point is that after a clean-up there can be no problems at all with newly produced milk products. If there are fresh problems, they must be even more sternly punished under the law."
China's food quality watchdog has said it found melamine in nearly 10 percent of milk and drinking yoghurt samples from three major dairy companies: Mengniu Dairy Co, the Inner Mongolia Yili Industrial Group and the Bright group.
Nitrogen-rich melamine can be added to watered-down milk to fool quality checks, which often use nitrogen levels to measure protein.
China's dairy producers face a "crisis of confidence" that will need strong government steps to cure, said Lao Bing, manager of a Shanghai-based dairy investment company.
"How long the industry takes to revive will depend on how vigorous those steps are," he said. "Consumers will start rebuying in a month or two if they feel sure the government is undertaking a vigorous clean-up ... Exports will take longer. This will have a major impact."