The swift trial and the harsh sentences Thursday show Beijing's resolve in tackling the country's stubborn food safety problems and an eagerness by the communist leadership to move past the embarrassing scandal.
With six babies confirmed dead and some 300,000 others nationwide suffering kidney stones and other problems from drinking melamine-laced formula, public shock has turned to simmering anger since the contamination was exposed in September.
That fury has been further stoked by reports of an apparent cover-up by companies involved and safety officials ignoring tips and warnings from parents and doctors. Many Chinese are suspicious that high-level pressures for a successful Beijing Olympics in August made people aware of the crisis afraid to speak out, even as babies were dying.
The dairy boss sentenced Thursday, Tian Wenhua, has admitted she knew of problems with her company's products for months before informing authorities.
In a reflection of the trial's sensitivity, dozens of police officers guarded the Shijiazhuang city courthouse in northern China and cordoned off the surrounding area with plastic barriers. Officers told the victims' families to keep about 100 yards (meters) away.
The Intermediate People's Court in Shijiazhuang gave a life sentence to Tian, 66, the former general manager and chairwoman of Sanlu Group Co., the dairy at the center of the crisis. She was the highest-ranking executive charged in the food safety scandal.
Tian had pleaded guilty to charges of producing and selling fake or substandard products.
Some of the victims' relatives, who stood outside for hours in freezing weather, said Tian got off lightly.
"My granddaughter died. She (Tian) should die too, she should be shot. She has brought such harm to the public, to children," said Zheng Shuzhen, of Henan province, who said her 1-year-old granddaughter died in June after drinking Sanlu milk.
Liu Donglin, a father from Beijing whose 21-month-old son has kidney stones, said he would continue calling for the government to study the long-term health effects of melamine.
He also planned to fight a proposed $160 million compensation plan proposed by Sanlu and 21 other dairy companies involved in the scandal. More than 200 families have filed suit demanding higher compensation and long-term treatment for their babies.
"We'll keep pushing for one year, two years, three years, even 20 years until our children get what they deserve," he said, holding up small signs with other parents that said "Return my child" and "Justice for the people."
Investigations showed that middlemen who sold milk to dairy companies such as Sanlu were watering down raw milk, then mixing in melamine to make it appear to have a higher protein content.
One of those middlemen, Geng Jinping, who supplied hundreds of tons of melamine-tainted milk to Sanlu, was sentenced to death. Also condemned was Zhang Yujun, who ran a workshop that produced melamine-tainted powder branded as protein enriching.
Wang Yuliang, a former deputy general manager at Sanlu, who was in a wheelchair because he lost use of his legs apparently during a suicide attempt, was sentenced to 15 years' jail.
A lawyer advising victims' families said the death sentences and life terms were "cruel and heavy."
"It was a problem of the system, but they were brought to court as scapegoats," said Li Fangping. "No government officials were charged for failing to fulfill their inspection responsibility."
The government promised in 2007 to overhaul inspection procedures after exports pet food ingredients killed and sickened pets in North and South America. The chemical in the dangerous pet food was the same as in the milk scandal — melamine.
But promises of official oversight fell flat in the booming dairy industry. Unlike the United States where dairies run farms with thousands of cows and are better able to control quality, milk in China comes from a patchwork of producers.
During her Dec. 31 trial, Tian admitted she learned of problems with her company's products from consumer complaints around mid-May of last year but didn't inform authorities until months later. The company did not stop producing and selling formula until September.
Tian was also fined 20 million yuan ($2.92 million) while Sanlu, which has been declared bankrupt, was fined 50 million yuan ($7.3 million).
Among the 21 convictions announced Thursday, a third man was given a suspended death sentence which is usually commuted to life imprisonment, two others were handed life terms, while the remaining 14 defendants were given jail terms of five to 15 years.
Normally used to make plastics and fertilizer, melamine can cause kidney stones and kidney failure when ingested in large amounts. The discovery of melamine in dairy exports such as chocolate and yogurt triggered a slew of product recalls overseas.