(AP) -- China declared a new food-safety campaign Wednesday after contaminated milk products from an earlier scandal showed up repackaged in several places around the country, exposing weaknesses in the country's promise to stop such problems from happening again.
Vice Premier Li Keqiang told the first meeting of a newly established food-safety commission that "We should understand the foundation for the country's food safety is still weak and the situation is grave," the state-run Xinhua News Agency reported Wednesday.
Li promised to "thoroughly" investigate the re-emergence of milk products tainted with the industrial chemical melamine, destroy all the products and punish those responsible, Xinhua said.
The vow came two days after state media reported that officials recalled 170 tons of tainted milk powder in the northern region of Ningxia and said almost 100 tons of the powder had not yet been found. Two dairies were closed.
An emergency 10-day crackdown on tainted milk products is set to end Wednesday, and the Health Ministry did not say whether it will be extended.
The original milk scandal in 2008 sickened hundreds of thousands of children, and at least six died.
China ordered tens of thousands of milk products laced with the industrial chemical melamine burned or buried. But the government did not carry out the destruction itself.
Some profit-hungry producers were accused of adding melamine to watered-down milk to make it appear to still be rich in protein in quality tests that measure nitrogen, found in both the melamine and protein. Health problems from the chemical include kidney stones and kidney damage.
Tainted dairy products have recently been found in China's largest city, Shanghai, and in the provinces and regions of Shaanxi, Shandong, Liaoning, Guizhou, Ningxia, Jilin and Hebei.
At least five companies are suspected of reselling tainted products that should have been destroyed, the Health Ministry said last week.
The problem products uncovered have so far been limited to the domestic market.
The Health Ministry has not commented since the new crackdown began, and the China Dairy Association has remained quiet as well.