Testing in China on a dairy product manufactured in New Zealand has detected low levels of contamination with melamine, but food safety officials have declined to name the product or its manufacturer.
Food Safety Minister Lianne Dalziel said today the highly-refined dairy product was picked up by testing in China.
"It was discovered in testing for melamine that a New Zealand company, in New Zealand, producing a highly specialised ingredient derived from milk has tested positive for extremely low levels of melamine," she said.
The levels detected were "minute" and were not regarded by the Government as having a health risk. She suggested that the melamine could have leached into the food from plastic packaging.
New Zealand Food Safety Authority (NZFSA) compliance and investigation director Geoff Allen told NZPA the authority was unable to provide more detail at this stage "as the information we have been given has not been officially confirmed".
Asked how melamine could be detected in product when research had shown that migration from melamine-containing resins to food and drink suggested such contamination might only be around 1 part per million (PPM), he said the product involved had been concentrated several thousand times in processing.
Some specialised NZ dairy products, such as lactoferrin -- a milk protein claimed to boost a person's immune system -- require as much as 10,000 tonnes of milk to make one tonne of finished product.
Mr Allen said NZFSA was also considering any role which might have been played by cyromazine, an insecticide which breaks down to melamine in mammals.
"The possible contribution of breakdown products from cyromazine is being included in the investigations that are underway," Mr Allen said.
"At this stage we can make no comment on the degree of contribution, if any." NZFSA would release publicly the results of its investigation, and the likely pathways for the contamination into the food.
NZFSA has 24 livestock drenches and sprays listed among registered agricultural compounds on its website, some of them registered as recently as last month.
Asked about the extent to which cyromazine is being added to stockfood, including feed for poultry, in NZ, Mr Allen said that would have to be answered by the industries involved.
In June, NZFSA published a list of contaminant levels it will allow in animal products, and specified a maximum permissible level of cyromazine and melamine in 0.3mg/kg in sheepmeats, and 0.15mg/kg in poultry and eggs.
But it admitted on Tuesday that it does not actually have an acceptable level of contamination for New Zealand foods.
NZFSA has said its officials are waiting on a European Food Safety Authority (EFSA) scientific opinion on risks to human health from low levels of melamine in products.
There is a generally accepted "tolerable daily intake" of melamine in food in the European Union (0.5mg for each kg of body weight daily) and in the US (0.63mg/kg of body weight/day).
But the NZFSA's principal adviser on toxicology, John Reeve, said that while the agency is aware of tolerable daily intake levels set by the EFSA and the US Food and Drug Agency (FDA) it had no acceptable daily intake for New Zealand.
Chan King-ming, an associate professor of biochemistry at a Chinese university, said this week that cyromazine, a derivative of melamine, has been widely used as an insecticide.
According to Prof Chan, cyromazine is absorbed into plants as melamine and has spread through the food chain in animal feeds.
The Green Party's food safety spokesperson, Sue Kedgely, said the public had a right to know immediately which products are being tested.
She said not naming the company was out of line with Prime Minister Helen Clark's comments that companies involved in the melamine milk poisonings in China, such as Fonterra's Sanlu joint venture, should have spoken out publicly earlier.
