As a result, China's high-profile nationwide campaign to boost science and scientific research is being reconsidered with an eye to social responsibility, and the possible "economic adulteration" of all Chinese products.
The scandal broke in September after melamine-polluted milk killed four babies and sickened as many as 60,000.
It spread from the milk industry to the animal feed industry in late October when Hong Kong authorities found melamine in eggs imported from the mainland - the result of tainted feed given to chickens. There have been subsequent reports of melamine found in feed for pigs, cows and fish, prompting fears that meat and meat products could be contaminated.
China's state news agency Xinhua reported on Wednesday that 1,272 infants are still hospitalized in China with at least two of the babies in serious condition. Ingesting melamine can cause kidney stones and lead to kidney failure in young children.
But scientists say warnings signs were apparent as early as last year when melamine in Chinese-made pet food killed house pets across the United States.
"You can't separate the food supplies of animals, pets and people," Marion Nestle, a public health professor at New York University and author of the recent book Pet Food Politics: The Chihuahua in the Coal Mine, told the Washington Post. "That's an enormous warning sign that if something wasn't done immediately to clean up the food safety problem, this would leak into the human food supply."
China has used the Kjeldahl Nitrogen Determination Method to measure protein level in food, meaning the content of protein is determined by the level of nitrogen. It is an open secret in China that melamine is added to milk and animal feed to artificially boost nitrogen levels. It was not until recently, after the exposure of the tainted-milk scandal, that China make it compulsory to test the content of melamine in foodstuffs.
While unscrupulous milk and fodder producers - and subsequently the government - came under public accusations for making and covering up melamine-contaminated products, angry Chinese consumers are now pointing fingers at scientists.
The prestigious, government-funded CAS was among the first to be linked to the chemical.
Last month, Chinese bloggers exposed that as early as in 1999, a CAS institution placed advertisements for an additive to cattle feed called "DH Composite High-protein Fodder Supplement". The advertisement claimed that the technology could be used to manufacture "high protein fodder using organic nitrogen and special catalysts".
The technology was sold by the Appliance Technology Institute of CAS for 10,000 yuan (US$1,466) plus an extra 5,000 yuan ($700) for training, according to the advertisement. The online ad was soon posted on major websites and forums. Many believed that "DH Composite High-protein Fodder Supplement" was based on melamine.
The CAS, however, was quick to deny the charge. Jiang Xiezhu, spokesman of the CAS, told the media that an investigation launched by the academy showed that the supplement "had nothing to do with melamine". His explanation was that the advertised technology could not produce the high temperature needed for the production of melamine.
Few are convinced by the explanation, however, because the investigation was done unilaterally by the CAS. Without an independent observer, people began to doubt the objectivity of the results. And while denying that "DH Composite High-protein Fodder Supplement" is based on melamine, the spokesman also failed to publicize its formula or ingredients.
The CAS also failed to mention who invented the technology. It only said that the contact person named in the advertisement, Gao Yinxiang, was not a scientist, implying that Gao was not the inventor.
This is not true. In an interview with the Beijing Evening News, Gao acknowledged taking part in the development of the product. The Beijing Evening News later exposed Gao as a former director of the Appliance Technology Institute of CAS, and a biologist.
It's not clear whether the CAS deliberately hid Gao's identity. However, the process of investigation and the contradictory statements made the CAS's explanation quite weak. Even commentaries in major newspapers demanded the CAS give a more thorough clarification.
In China, various kinds of "Protein Essence", or additives to boost the protein levels of products, have been readily available for purchase.
Chen Junshi, a research fellow of China's Disease Prevention and Control Center, said that the main ingredient of these "Protein Essence" additives is melamine. The Chinese government began to ban "Protein Essence" after melamine-tainted pet feed killed pets in the US last year. Gao insisted that his supplement was not a "Protein Essence", although he remained vague about what exactly his supplement was.
More scientists under fire
It might never be known whether the CAS invented the melamine supplement. Still, the online ad did reveal a fact: China's top government-funded science institution researched chemical fodder supplements nine years ago for profit.
Making chemical additives can be highly profitable. Industry insiders say that the price of melamine was only 600-800 yuan per tonne, but its price could jump 500% to 4,000 yuan a tonne when it was made into protein supplements.
As the Washington Post reported, "Melamine is used to make fertilizer and plastic but the factories where it is made regularly sell melamine scraps to whoever wants them. The scraps, in turn, are frequently used to make protein powders that are used to spike animal feed and watered down milk in order to pass protein tests."
A November 10 blog hosted by the Washington Post and titled "The Mathematics of Melamine" published an excerpt from an article that ran in Chemistry World, a publication of the Royal Society of Chemistry based in the United Kingdom:
Industrial melamine costs about 12,000 yuan (US$1,765) per ton, much higher than the price of milk - 1,200-1,800 yuan per ton. But the practice of adding melamine to milk is profitable because just one gram of melamine per kg of milk is enough to lift the apparent protein content of milk from less than 27 grams of protein per kilogram (the cheapest grade of milk in China) to greater than 31 grams per kilogram - the most expensive grade. So for 0.012 yuan (0.0018 US cents), producers can illegally boost the price of a liter of milk from 1.2 yuan (17.6 US cents) to 1.8 yuan (26.5 US cents) per kilogram. If the milk is diluted, the resulting profits can be even greater.Driven by such profits, biologists have been eagerly developing cheap fodder supplements made from chemicals, which, according to industry insiders, are used on far more than cows and chickens.
According to Zheng Shixuan, board chairman of Guangdong Yuehai Fodder Group, "Protein Essence" has been used in the feed industry for at least five years - at the cost of public safety. International health authorities have warned that melamine could lead to fatal kidney failure as early as 1994.
Gao was not the only scientist suspected of making melamine fodder additives. According to the Southern Metropolis Daily, another research institute under the CAS, the CAS's Senior Experts' Technology Center in Shanxi province, developed a protein supplement called "DH Protein Essence" in October 2007. A description of the supplement said that adding it could boost a product's protein content 160-200%. The CAS is yet to give an explanation on the product.
Another well-known biologist Wang Houde was also suspected of inventing a "melamine supplement", after Chinese bloggers found Wang's name in an ad selling a "Protein Essence". The ad claimed that this "Protein Essence" was a patented product of Wang and described it as a cheap alternative to high-protein fodder.
Wang denied the accusation. He said the technology was developed by Nanjing University in 1989 and the Ministry of Agriculture never banned it from the fodder supplement industry.
Next on the menu
The rampant use of chemical additives in animal feed can be traced to 1999. According to Gao Yinxiang, the research and development of high-protein feed additives was a hot field among scientists about 10 years ago due to shortage of animal fodder in the country at the time.
From that time, it's hard to define the exact role that scientists played in the evolution of the melamine scandal. Yet scientists certainly contributed to it by developing unsafe protein alternatives. Many Chinese are now calling on scientists to examine their conscience before making profits at the expense of public safety.
The CAS may not have invented melamine additives. However, it still owes the public an explanation as to why it developed - and continues to develop - feed supplements that food experts say are dangerous for human health.
The melamine saga and the reactions from relevant parties, including scientists, the government and the related companies, shows a system that continues to shirk responsibility rather than taking efforts to avoid similar incidents happening again.
Without effective supervision and sound accountability, China's food scares are far from over.
Stephen Wong is a freelance journalist based in Shanghai.