Li Changjiang, head of the General Administration of Quality Supervision, Inspection and Quarantine in China since 2001, has resigned just one year after promising to overhaul the system. Li was forced out in the midst of the tainted baby formula scandal, which has so far killed four babies and sickened nearly 53,000.

According to Beijing authorities, China's biggest producer of powdered milk had known for months that its baby formula was tainted with the industrial chemical melamine. Complaints about the infant formula date back as early as December 2007.

China Central Television said in a report on Monday, "During these eight months, the company did not inform the government and did not take proper measures, therefore making the situation worse."

Melamine has since been found in infant formula and other milk products from 22 of China's dairy companies. In babies, melamine can cause kidney stones and kidney failure.

Baby formula as well as other milk products have been pulled from store shelves around the country. Chinese goods, including liquid milk, instant coffee mix, and milk-based candy have been banned around Asia.

After a string of warnings and recalls abroad over tainted toothpaste, pet food, faulty tires, and other goods, new regulations and procedures were introduced in an attempt to restore consumer confidence and preserve export markets. However this latest crisis only proves that problems were still able to slip through undetected.

Sanlu and several other leading companies that were found to have produced the tainted milk had been given inspection-free status by China's product quality watchdog. However the privilege has since been taken away.

The World Health Organization urged Monday the stricter monitoring of the inudstry, and said that rescinding their inspection-free status was only the first step China needs to take. WHO also said that quality issues can crop up at any point in the supply chain, from the farm to the store, and needs to be carefully monitored at all points.

The number of sick children reported by the government also jumped over the weekend, from 6,200 to 53,000. More than 80% of the 12,892 children hospitalized in the past few weeks were 2 years old or younger, said the Health Ministry, and 104 were in serious condition. An addition 39,965 children received outpatient treatment and were considered "basically recovered." Four deaths have so far been blamed on the tainted milk powder.

According to China's official Xinhua News Agency, Li steppted down with approval from China's Cabinet. Replacing Li as director of the General Administration of Quality Supervision, Inspection, and Quarantine is Wang Yong.