With the other, she dug through her purse for the near-empty bag of milk powder she worried had sickened him.

'Is this brand OK?' she asked, holding up the packet of Bei Yin Mei formula. 'I'm still not sure. I don't have time to watch the news.'

Nor does she have the time to breast-feed her baby.

The number of Chinese women who rely on breast milk alone to feed their newborns has dropped as working mothers have less time to nurse and fall prey to advertising about the benefits of infant formulas.

Such economic pressures have taken China's tainted milk crisis to every corner of the country. They also explain why a country disgusted by an even deadlier fake baby formula scandal four years ago has been so badly hit again.

More than 54,000 children have been sickened by tainted milk products so far. Four deaths have been blamed on the products.

As the scandal grows, the World Health Organization and Unicef are publicly declaring breast-feeding as the healthiest option for babies.

But it's not an option for many women like Mdm Yang, one of Shanghai's millions of migrant workers, who spends most of her waking hours on the job.

Less than two months after giving birth, she stopped trying to pump her breasts before and after work on a construction site and switched to milk powder. She worried her own milk, and her time, was not enough.

Then the tainted milk scandal broke and, like millions of other Chinese parents, she suddenly had to ask if the formula she was feeding her son might kill him.

Fortunately, Bei Yin Mei's infant formula was declared melamine-free by authorities and Mdm Yang's son was given a clean bill of health by doctors.

But thousands of other babies have been hospitalised with kidney stones or kidney failure from the milk powder they drank.

The melamine scandal follows one in 2004 when 12 babies in eastern China's Anhui province died of malnutrition after drinking fake powdered formula. More than 200 babies suffered wasted limbs and swollen heads - common symptoms of malnutrition.

Baby formula and other substitutes, such as soy milk, rice porridge, and cow or goat milk, are necessary staples in rural areas where many young parents are forced to leave their children at home with grandparents or relatives to find work in the cities.

'The countryside doesn't have any more young people. Even the young women who could breast-feed for you are gone,' said Ms Yang Li, a migrant worker from central Chongqing who was selling bags and watches along a Shanghai street. 'It's difficult. You have to make money.'

The latest figures from China's Ministry of Health show that 71.9 per cent of mothers of infants under 4 months practiced breast-feeding in 2007. The rate is similar to that in the US, but lower than in many European countries.

Austria, Denmark, Finland, Italy, Luxembourg, Norway, Russia, Sweden and Turkey all have general breast-feeding rates above 90 per cent.

But health experts say figures on China's nursing habits can be misleading because the number of mothers who exclusively breast-feed - who don't supplement breast milk with animal milk, commercial formula or other substitutes - is actually declining.

According to the Chinese Food and Nutrition Surveillance System, 76.6 per cent of rural women exclusively breast-fed their children in the first four months of life in 1998. But by 2002, only 60 per cent of rural women were exclusively breast-feeding their newborns.

Ms Ling Shi, a researcher in family and reproductive health at the Johns Hopkins Bloomberg School of Public Health in Baltimore, blames the decline on the unpopularity of pumping breast milk and the surge in migrant labor.

But she says TV commercials are also to blame.

'There are a lot of advertisements now on Chinese television showing the cute baby face and the formula milk and they are talking about all the advantages and strengths of the baby formula,' said Ms Ling. 'These advertisements deliver some very wrong messages to families.'

In China, generations raised on food rations often see baby formula as a status symbol, giving it to new mothers as gifts.

'Some people even think feeding with milk powder is a way to show off,' said Ms Dai Yaohua, a researcher with the Beijing-based Capital Institute of Paediatrics.

Breast-feeding supporters say a strong message is needed to fight the baby milk formula industry, which has a powerful voice in China.

It spent US$765 million (S$1.09 billion) on advertising last year, according to Nielsen Media Research figures. Spending this year seems to be on the rise, with US$657 million in advertising as of the end of Aug.

Mdm Yang and other migrant worker mothers in Shanghai said they had believed milk powder was not just a healthy alternative to breast milk, but one that could make their babies smarter.

One brand that had not been removed from some Shanghai shelves over the weekend, Dumex, features a dolphin in a mortarboard cap and the letters 'IQ.' Unicef has criticised such product claims as extreme and unethical. China's Unicef communications chief, Bill Rutstein, said the organisation is working with China's Health Ministry to prepare pro-breast-feeding announcements for national television.

'Ideally, all infants should be fed exclusively with breast milk for the first six months of life, said a statement released on Thursday by the China offices of Unicef and the WHO.

The tainted milk crisis has driven Chinese worried mothers of every income to find alternatives to milk powder, with wet nurses becoming popular again. But that's a solution left mostly to the wealthy.

For now, some Chinese women are offering to share or even sell their breast milk.

Prices for wet nurses, or hired breast-feeders, have almost doubled to more than US$1,750 a month since the milk scandal began, said Mr Ai Xiaoxiong, human resources manager for Shenzhen Zhongjia housekeeping company, which offers the luxury service.

The number of wet nurses at the Rain Household Care Co. in Guangzhou has doubled to six since the scandal began, founder Mr Zheng Rong said.

'Most people still don't trust feeding their babies stranger's milk, but more realize now that it's better than taking chances with milk powder,' Mr Zheng said. Most of the wet nurses are migrant workers, and most of the clients are middle or upper class.

In Shanghai, new mother Ms Chen Jiren isn't doing it for the money.

She shares her breast milk with friends, most of them working mothers like herself but too busy to breast-feed.

'I didn't want to waste it,' she said. She manages to pump while working in sales at an IT company.

There's still much confusion among Chinese women about breast-feeding, said Ms Ren Yuwen, who began leading the first Chinese-language meetings in Shanghai this year for La Leche League International, a group that promotes breast-feeding.

Even during the latest milk powder scandal, most of the calls Ms Ren gets from young mothers are about mothers-in-law or neighbours pressing them to give their babies formula.

'Chinese mothers don't have any support, actually,' she said.

'Every time I get these phone calls, I feel sad.' -- AP