By Andy Ho
OUR supermarkets usually make it known where their produce comes from. If it is China, 'melamine' comes to mind, together with images of Tian Wenhua, former head of the Sanlu Group, being hauled to court last week.
Her company, which used to be one of China's biggest dairy producers, was at the centre of the tainted milk scandal that has seen at least six deaths and nearly 300,000 kids developing kidney stones. The cause was melamine added to milk to make it appear more protein-rich. Melamine has caused bladder cancers in lab animals.
Tian, who pleaded guilty, awaits sentencing. Punishing her and others involved might quell public anger, perhaps even prevent a repeat of the scandal. But the widespread presence of melamine in the food chain - in not just milk and diary products but possibly also meat, poultry and even fresh produce - may not go away.
Last October, eggs in China were found to have melamine because of tainted chicken feed. Earlier, in April, the authorities in the United States discovered that hog feed imported from China was tainted with melamine too. Much has been said about the globalisation of food chains: If there is intentional adulteration at source, melamine will find its way worldwide. But there is a less well- known problem: the unintentional addition of melamine to food.
During the scare, while most food safety agencies were busy testing food products imported from China, a research lab in Malaysia asked domestic food manufacturers to send in their ingredients instead. The lab discovered that baking soda, also imported from China, was heavily contaminated with melamine as well, both being white powders.
On further investigation, it was found that the factory that produced this baking soda also churned out melamine, as well as fertilisers and pesticides. Thus, even if there were no intentional adulteration, the use of the same machinery in Chinese factories to produce different chemicals could lead to the unintentional adulteration of food ingredients, like baking soda.
Moreover, through contaminated pesticides and fertilisers, melamine could also end up in fresh produce and vegetable products. It may find its way into animal products if livestock grazes on land where unintentionally contaminated pesticides and/or fertilisers are used.
Moreover, melamine has many legitimate uses, so it is found widely in the environment. Because it has flame resistance and smoke suppression properties, it is widely used in floor laminate, counter tops (as Formica), glues, adhesives, moulding compounds and flame retardants. Its use in adhesives alone means that it may appear in food sold in cardboard boxes, ranging from cookies to pizzas, a fact recognised and permitted by the US Food and Drug Administration.
A new use for melamine is to line and coat clear, flexible packaging for food products, like pre-packaged washed salads. (Pure melamine exists as clear, needle-like crystals.) The melamine is impermeable to gases, so oxygen cannot get in to spoil the food. As a coat, it is also easier to print on than the conventional metallised coat used for flexible packaging.
As if that were not enough, what you eat may be flavoured with even more melamine from another source. Because of its heat resistant properties, melamine has also been used to make dishware for a long time. Locally, melamine-ware such as bowls, plates, spoons and chopsticks are widely used at food courts, coffee shops and hawker stalls.
A British study published in Food Additives & Contaminants reported that 86 per cent of new melamine-ware bought in Britain in 2005 leached melamine. In addition, all of them leached formaldehyde, a known carcinogen. The use of formaldehyde was banned in the European Union last September.
Way back in 1992, a Japanese study published in the Journal Of The Food Hygienic Society Of Japan had already reported how melamine cups and mugs, used to sell hot drinks in a cafeteria, were tested after four years of use and found to be still leaching melamine.
A recent World Health Organisation advisory noted that melamine can be leached by 'acidic foods, such as lemon or orange juice or curdled milk, at high temperature'. So just use ceramic ware instead.
It might infuriate China to say so, but until the country is seen to be clearly enforcing its food safety rules and manufacturing regulations, one might as well give its food products a complete miss.
In this way, other noxious substances may be avoided as well. For instance, the China Veterinarian Science Information Network reported in 2007 a study that had found early cancer cells in 68 per cent of 200 samples of pork liver sold in Guangzhou. The cause was suspected to be the life-long exposure of pigs to high doses of several pharmaceuticals.
In September 2006, the Xinhua News Network reported 300 Shanghainese being hospitalised after falling ill from consuming pork tainted with drugs such as salbutamol, serbutaline and clenbuterol. Chinese farmers feed their pigs these drugs believing that they produce leaner meat which consumers love.
Food agencies might well test imported products for melamine or other contaminants but what if the products were made from animals or poultry that have died from illnesses?
A University of Houston study published in the Journal Of Agricultural And Environmental Ethics last month reported field observations in China that confirmed reports of chickens and pigs that had died from diseases being widely sold domestically through well-established networks. It noted that such reports had surfaced in China Animal Quarantine in 2001 and Meat Hygiene in 2004 as well.
Perhaps such food may never reach our shores. Then again, it just might. Consumers would do well to be careful.
[Dr Ho is not an alarmist so any warning from him deserves serious consideration. But leaching melamine from plates should not be a major concern. Micro "doses" of harmful substances are ingested by us everyday. On the whole our bodies can deal with "ambient" toxins. But the other practices - melamine in feed, drugs in livestock, etc, is cause for concern.]