Sanlu chief Tian Wenhua is awaiting sentencing following the end of her trial
Chinese dairy companies involved in the tainted milk scandal have apologised in a New Year text message sent to millions of mobile phone subscribers.
"We sincerely apologise...and we beg your forgiveness," read the note from 22 dairy firms, led by Sanlu, China's state news agency said.
At least six babies died and 290,000 became ill from melamine contamination in milk products made by the companies.
Melamine was added so the milk appeared to have a higher protein content.
"We are deeply sorry for the harm caused to the children and the society," the text message said. "We sincerely apologise for that and we beg your forgiveness."
It said a compensation fund had been established for the victims, including the families of thousands of babies still suffering from urinary problems such as kidney stones.
The chairwoman of Sanlu, Tian Wenhua, pleaded guilty to selling fake or substandard products at a trial that recently concluded in northern China.
She is expected to be sentenced to life imprisonment although a verdict may not be reached for several weeks, the official Beijing News said.
Earlier reports indicated that the 66-year-old executive could face the death penalty.
In the past week, another 17 people involved in producing, selling, buying and adding melamine to raw milk have also gone on trial.
Sanlu said it discovered the problem in May and reported it to authorities in Hebei Province on 2 August.
But nothing became public until early September, when the New Zealand government said it brought complaints by Sanlu's partner, Fonterra, to the attention of the Chinese government.
Meanwhile a group of parents whose children drank the tainted milk have reportedly been detained by police.
A father of one ill child said Beijing police tried to block them from holding a news conference, and added that some of the group - including him - were detained for a while and are now under house arrest.
But a small press briefing did go ahead on a Beijing pavement, with parents complaining about lack of government support.
"The government said all the medical care is free, but when it comes to the local level, things change. I have already paid more than 50,000 yuan ($7,300, £5,000)," one man from Sichuan province told Reuters.
"We are here today to claim rights for our babies," Lan Juanxian, the mother of 14-month-old twin sons, told the BBC.
"Our babies have been diagnosed with kidney stones, but we don't know what other diseases they will contract when they grow up," she added.
"The issue of adding melamine into food is a new problem, no one has scientific information or evidence," added 33-year-old Jiang Yalin.
"We are asking for research on how much damage melamine can wreak," she told reporters.