Scientists have found a bacteria living in the gut that makes melamine more toxic – a finding that could explain why some children in China died and others lived after drinking milk tainted with the chemical in 2008.
In a study on rats, scientists at the University of North Carolina Greensboro and the Shanghai Jiaotong University found the germ Klebsiella terrigena metabolises melamine to create a more toxic byproduct called cyanuric acid.
Rats who were given antibiotics to kill the germs excreted twice as much of the melamine as rats that didn’t get antibiotics, and they experienced fewer kidney stones and other damage.
Back in 2008, the melamine laced milk killed at least six babies and left 300,000 sick, many suffering from kidney stones and renal failure.
The milk produced by the Shijiazhuang-based Sanlu Group  was pumped with the chemical to appear to have a higher protein count level. Melamine was thought to have low toxicity and to not be absorbable by the human body. But when mixed with cyuranic acid even small doses of melamine could lead to kidney failure.
While the human gut teems with bacteria performing different roles in digestion , the bacteria Klebsiella terrigena is not commonly found.
Previous studies estimate that fewer than 1 per cent of healthy people harbour that species, and a similar fraction of melamine-exposed children in China got sick, the researchers wrote. But proving that link would require studying stool samples preserved from affected children, they cautioned.
What do other researchers think? The research is pretty strong, said microbiologist Jack Gilbert  of the University of Chicago and Argonne National Laboratory, who wasn’t involved in the new study.
"This paper adds to a growing body of evidence which suggests that microbes in the body play a significant role in our response to toxicity and in our health in general”, Gilbert said to the AP.
Four years after the scandal, concerns over food safety in China continues, and demand for milk powder imported from Hong Kong, where safety standards are considered much better than on the mainland, remains high.
The demand has made it difficult at times for Hong Kong parents to find baby formula for their children, forcing the government this month to impose a two-can limit on the number of cans a person can take out of the city.
Additional reporting by AP.