Parents whose children were sickened or killed by contaminated milk powder were left furious after police admitted that the sentencing of the culprits behind the scandal was too lenient and may not prevent similar crimes in the future.

Xu Lu, deputy director of the social order bureau at the Ministry of Public Security, said food safety laws should be strengthened.

He spoke during a ceremony to mark the opening of a food safety law research center in Beijing on Sunday.

"Take the nationwide melamine-tainted milk scandal, for example. The culprit who was involved in selling more than 10 tons of the tainted milk powder was sentenced to only three years in prison, with three years probation," he was quoted by the Beijing News as saying. "Lenient sentences like this cannot stop similar crimes from happening again."

In July, police seized 64 tons of milk powder in Qinghai Province that contained excessive levels of melamine. "When we were trying to catch a high-level official at one dairy plant involved in the July scandal in Tianjin, he said to our face and told his families that 'don't worry, only three years in jail at the most,'" Xu said.

Liu Huan, mother of a 3-year-old girl who suffered from kidney stones and kidney damage after drinking tainted milk, said that the government should adopt more serious punishments for perpetrators.

"The sentence for offenders is too light but the pain for victims' families is too heavy," Liu said. "If I were the judge, I would give the death penalty."

China set up its first food safety law research center on Sunday made up of 100 high-level officials from legislative and food safety departments.

Zhang Xingshui, a member of the China Law Society, said the center could help to address legal loopholes.

The new Food Safety Law went into effect on June 1, 2009 following the Sanlu melamine-tainted milk scandal in 2008.

Under the law, offenders can face maximum fines that equal 10 times the value of sold products and face having their food production licenses revoked.