By Michael Bristow
BBC News, Beijing
China's growing scandal involving milk powder suggests the country is still not able to protect its citizens from tainted food products.
Parents are queuing at hospitals for check-ups for their children
Despite many other recent cases involving sub-standard food, inspectors failed to prevent toxic milk powder being fed to children.
Strict laws but poor enforcement appears to be part of the problem. China also seems to have a number of unscrupulous suppliers.
Chinese consumers are only too aware of the problems, as they have shown by buying more trusted foreign brands of milk powder.
At the centre of this current scandal is the Sanlu Group, a company based in the city of Shijiazhuang in Hebei province.
It has been selling milk powder tainted with the toxic chemical melamine, used in industry to make such things as plastics.
This chemical makes the milk powder appear to contain more protein than is actually the case.
So far, three children have died and more than 6,000 have been taken ill after drinking the powdered milk. Nearly 160 have experienced acute kidney failure.
All the children who became seriously ill drank milk made with powder produced by Sanlu, according to Chinese health minister Chen Zhu.
But the scandal is not limited to just one company.
In a development that will surely worry the government, inspectors have found melamine in milk powder produced by 22 companies - one out of every five suppliers.
China's laws do not seem to be the main problem, according to a senior employee at a foreign firm that produces baby products in China.
"There are laws and the laws are very strict. When we want to launch a product, there are so many things we have to do," said the employee, who did not want to be identified.
Chinese central government officials often complain that these good laws are not heeded, a claim backed up by the industry insider.
"There is a lot of corruption, and Chinese companies can often find ways to carry on producing," she said.
In order to avoid the problems now facing Sanlu, this foreign firm sends its own inspectors to check products bought from Chinese suppliers.
As well as being prepared to bend the rules, some Chinese suppliers also seem willing to knowingly supply tainted food products.
In this current case, melamine appears to have been added to fresh milk at milk collection stations, before being passed on to Sanlu.
According to the state-run China Daily, one man arrested over the scandal confessed that he had added melamine to milk, despite knowing it was a health risk.
He added that his family never drank the contaminated milk.
As a senior official put it at a press conference on Wednesday, China does not test for melamine because it does not expect anyone to add it to milk powder.
Tian Guangcai only feeds his grandchild imported formula milk
"There are no special requirements on the inspection of toxic chemicals
because these kinds of chemicals are not allowed to be added to food," said Li Changjiang, head of the country's quality watchdog.
Perhaps the most damning indictment of the system comes from Chinese consumers, who have to eat and drink the products bought in markets, shops and supermarkets.
"It's outrageous, nobody can eat anything any more," said Tian Guangcai, who looks after his four-month-old grandchild.
Mr Tian said the child - like many other Chinese children - only drinks milk powder made by foreign companies.
Those foreign brands are now flying off the shelves.
Wang Wenli, whose three-year-old son stopped drinking milk powder last year, is now even reluctant to let him drink fresh milk.
"Think about it, if there's a problem with the milk powder then there is likely to be a problem with fresh milk too," she said.
The government's reaction to a baby milk scare in 2004 shows just how difficult it is for consumers to judge what is safe to consume.
At that time, parents were told they should select one of 30 approved brands.
This latest check has revealed that products from some of those approved firms contained melamine.