One of the world's biggest exporters of hugely expensive dairy protein lactoferrin has suspended exports in order to clarify how it was contaminated by melamine.
Morrinsville-based Tatua Cooperative Dairy Company Ltd said today it expected dairy exporters were in future likely to test for melamine contamination before releasing product for sale.
China this month shut down production at dairy company San Lu after its baby formula was found contaminated with melamine, leading to the deaths of four infants.
Tatua's board will meet tomorrow, and is expected to discuss the contamination.
A Chinese customer told Tatua's agent two weeks ago that melamine had been detected in its product in China.
Further tests were done in both in China and New Zealand, and results on September 22 and 23 confirmed contamination at less than four parts per million.
The New Zealand Food Safety Authority (NZFSA), inspected the factory on September 24.
Tatua chief executive Paul McGilvary told NZPA today the company's own investigation detected no melamine in its raw milk.
"With the NZFSA we've now mounted a traceback project," he said.
The NZFSA has no legal maximum residue level (MRL) for melamine in milk, even though in June it published MRLs for melamine at 0.3mg/kg in sheepmeats, and 0.15mg/kg in poultry and eggs.
The traceback was expected to canvass whether the melamine was introduced to the raw milk, either by farmers using insecticides containing cyromazine, an insecticide which breaks down to melamine in mammals and plants, or feeding dairy cows cheap imported feeds such as palm kernel contaminated with cyromazine or its metabolite, melamine.
The investigation has serious implications for dairy exporters, despite the other two manufacturers of lactoferrin, Fonterra and Westland, saying their products were not contaminated.
Though the NZFSA, and major multinational food companies including Nestle and Heinz have argued that melamine contamination does not pose a health risk, the Chinese dairy scandal involving Fonterra's joint venture Sanlu has triggered consumer sensitivities to any melamine contamination in foods.
Lactoferrin sells for about $500,000 a tonne and is used in baby formulas and "nutriceutical" dairy-based drinks for its claimed ability to boost the immune system.
Tatua's factory at Tatuanui near Morrinsville processes 10,000 tonnes of raw milk to extract just one tonne of the protein.
Mr McGilvary said the traceback could take months.
One problem the company was grappling with was that global markets had been sensitised to melamine contamination, and consumer perceptions were important even where contamination levels were so low they did not present a health risk, he said.
"There's quite a lot of sensitivity around melamine even at low levels," said Mr McGilvary, who suggested there were questions around the accuracy of detection tests at low levels of contamination.
"With the levels that we've found, you're on the limits of your ability to reliably test it," he said.
He could not account for why the two other NZ manufacturers of lactoferrin had not reported contamination, but said Tatua was not testing for melamine before in-market testing in China showed it.