Hong Kong mother Shirley Lo stocked her refrigerator with soymilk and switched to buying imported chocolates for her son after melamine was found in baby formula and milk products in China.
But when eggs from China tested positive for melamine in Hong Kong, Lo threw up her hands in despair.
The discovery of melamine in eggs, apparently due to contaminated feed
given to chickens, means the chemical is far more entrenched in
the human food chain than first thought.
"It's horrifying," said Lo. "It's clear it has gone into basic foods and into our food chain. My son has been trying to comfort me, saying he must be very strong because his body must be full of this stuff and yet he is not sick".
Finding melamine in eggs as well as in baby formula, milk products, biscuits, chocolates and other foodstuffs containing milk derivatives confirms what experts have long suspected; that the chemical is deeply embedded in the human food chain.
And it's not just melamine; heavy metals such as lead and mercury which can cause brain damage, as well as cadmium, a compound used in batteries, pesticides and antibiotics are all present in the human food chain.
China is a major transgressor as carcinogenic chemicals are regularly used as food colouring agents or as preservatives, experts say.
"In China, food safety is not a concern and all sorts of things like Sudan red, Malachite green are added in food, so food contamination is widespread," said Peter Yu, a professor of biology and chemical technology at the Hong Kong Polytechnic University.
"We also have environmental contamination from pesticides, formaldehyde (to kill bacteria)," Yu said, citing the use of Malachite green, a carcinogenic agent, that in 2006 was found in fish from China.
Leading food manufacturers regularly test their ingredients and final products for many of these contaminants, but experts say it's impossible to keep up with all the foreign compounds that land up on the dinner table, especially in China where regulation is lax and difficult to enforce.
In the wake of the melamine scandal, China is reviewing a tougher draft food safety law following criticism from the United Nations for its sluggish response to the tainted milk scandal.
Tens of thousands of children in China have fallen ill with kidney problems in recent months, and at least four have died, after being fed infant formula that was later found to have been mixed with melamine.
Subsequent tests found melamine in a variety of Chinese-made products from milk and chocolate bars, to yoghurt and other products exported around the world, leading to items being pulled from shop shelves and massive recalls.How vigilant are you about food ingredients? Do you regularly check labels? Do you buy food imported from China?