Chinese families have swarmed stores in Hong Kong selling foreign-made milk products as trust in China-made products plummets.
Normally, mainland visitors to Hong Kong flood to luxury goods stores for handbags and jewellery during the national holiday.
But China's toxic milk scandal, which has left 53,000 children ill and four dead has changed the desire for Gucci and Louis Vuitton.
Zheng, who lives in the neighbouring southern Chinese province of Guangdong, had travelled across the border to stock up on supplies. After the toxic milk scandal, she does not trust China made products.
"We will not go for mainland milk again. It is so dangerous," she told AFP.
"My daughter is expected to deliver a baby girl next week. We are worried about a potential shortage of formula
and thought it would be safer to buy more now. You can't expect a baby to come to this world without food, can you?"
Fears about drinking Chinese-made milk tainted with melamine have continued to grow.
The toxic chemical, normally used to make plastic, can make a dairy product appear richer in protein than it actually is, and unscrupulous farmers have been adding it watered-down milk to increase profits.
The scandal has been a public relations disaster for China, already reeling from a string of food safety controversies, and has led governments worldwide to impose massive recalls since it was revealed several weeks ago.
It has also exposed how many major milk and confection brands have been using China as a production base, unable to control the milk they were supplied with.
But the scandal has opened up new opportunities for overseas producers.
Mina Leung, a mother from Macau, said she took the one-hour ferry trip to Hong Kong with her husband just to buy more Japanese-brand formula for her baby.
"The product is not sold in Macau. We had been to three stores here and were told every time that there was no more stock. Fortunately, we found some in the fourth shop," she told AFP.
Alice Wong, a supervisor at Bonjour's city centre branch, said demand for overseas infant formula had rocketed.
"The scene at our store was terrifying. Mainlanders came here with their trolleys and each of them ordered at least 32 tins of infant formula," she told AFP. "They were searching every corner of the city for baby formula."
"We had to keep refilling the shelves as they were emptied out by the customers throughout the day."
The cosmetics and health care chain had to suspend its online ordering service after it ran out of stock several times.
It has also imposed a quota of eight tins per customer to prevent rival retailers from buying in bulk to sell on at a higher price.
Meiji, the most popular Japanese infant formula brand in Hong Kong, had already suspended its supply to the chain because it was now taking more orders than it could fulfil, said Wong.
The scenes have been replicated across Hong Kong, in particular at small chemists in districts close to the border, local media reports have said.
High-end organic food supermarket Three-Sixty has also been actively promoting dairy products imported from Australia, Britain, the United States and other non-Asian countries.
Wong, of Bonjour, believed that the food scare would have a wider long-term impact on Chinese buying habits.
"They are much smarter customers now," she said.
"They are now... asking for Japanese brand or overseas dummies, milk bottles, baby food, and nappies," she said. "In short, they have completely lost their confidence in homemade products."