New Zealand food safety officials who
have tested infant formula for melamine contamination, and are now
testing products containing Chinese milk say they have not yet set a
limit for melamine content in NZ foods.
They are waiting for data that will reveal a dietary level of
melamine that does not lead to formation of kidney stones before
setting an acceptable level of contamination in NZ foods.
In the meantime, NZ will rely on a European Food Safety
Authority scientific opinion to be issued later this week on risks
to human health associated with melamine in products that may have a
low level of contamination.
About 22 Chinese dairy companies are reported to have had
contamination detected, but the first reports and the highest levels
were in “Bei Bei” infant formula made by Fonterra’s Chinese joint
venture, Sanlu.
Big food companies overseas, such as Nestle, have said melamine
is found throughout the food chain across the world in minute traces
which do not represent any health risk for consumers.
There is a generally accepted “tolerable daily intake” of
melamine in food in the EU (0.5mg for each kg of body weight daily)
and in the US (0.63mg/kg of body weight/day).
Melamine traces which can be measured by commonly-used testing
equipment down to levels of 2 parts per million – 20 times below
these limits.
But the principal advisor on toxicology for the NZ Food Safety
Authority, John Reeve, said today that while the agency is aware of
tolerable daily intake levels set by the European Food Safety
Authority (EFSA) and the US Food and Drug Agency (FDA) the “NZFSA
has not yet established an ADI (acceptable daily intake) or its
equivalent for New Zealand”.
“It is important to remember that the science on this is very
new,” he said.
A lot of research was based on melamine found last year in
American pet foods that contained Chinese ingredients and killed a
lot of cats and dogs. That problem prompted recalls of more than 100
pet-food brands in the USA.
“Melamine on its own is not particularly toxic, however it is
the combination of factors such as the presence of other substances
in urine that appears to influence the development of crystals, (in
the kidney)” Mr Reeve said.
The basis on which the European limit had been set was not clear,
but the FDA figure was based on the “no observed adverse effect
level” for kidney stones in rats.
He said the formation of crystals of melamine in urine arising
from its insolubility and the concentration of bodily wastes in the
kidney was what was likely to be leading to the kidney failures
reported in Chinese babies brought up on milkpowder contaminated
with melamine.
“We simply don’t know enough at present to determine the
concentration of melamine that can reach levels that cause
crystallisation to take place,” he said. Recently born infant
children might not have fully functioning kidneys, and the American
kidney stone study was probably on rats with mature kidneys, which
would seem likely to be more tolerant to crystal formation.
NZFSA deputy chief executive Sandra Daly told NZPA that though
the agency was waiting on information from Europe, “NZFSA will act
on any level which is indicative that dairy product has been
adulterated for economic gain, regardless as to whether this may be
lower than that which may be tolerable toxicologically”. Products
which mainly consist of dairy ingredients would be the main target
of such checks, rather than multi-ingredient products where a
detection of low levels “may be associated with a coincidental
contamination of a minor ingredient” and where no risk was posed to
consumers.
The agency is testing White Rabbit Creamy Candy milk-based
sweets, after reports from Singapore that melamine has been found in
some of the milk-based lollies.
Ms Daly said a second report from Singapore had contradicted the
first. She did not believe there was not much risk to consumers,
even if the sweets did contain melamine, as there was a low risk of
people eating a lot of sweets with a high melamine content.
Ms Daly told the New Zealand Herald it was difficult for
laboratories to test products which were not liquid or powder for
melamine.
In China, four babies have died and China’s Health Ministry said
over 50,000 had been hospitalised with kidney problems.
So far four Hong Kong children have developed kidney stones,
after drinking Chinese-made Nestle milk, making them the first
victims of the tainted milk outside of mainland China.
