After a dairy products tainting scare this year, a government report shows traces of soil treatment product DCD were found in 371 samples, affecting mainly milk powder.
Traces were also found in 11 cheese products and one butter product.
The Government does not know where the DCD-tainted products went, though some would have been sold in New Zealand.
However, the DCD levels are "safe" and mostly less than 1 part per million, the report shows.
Dicyandiamide or DCD is a nitrogen inhibitor used on pastures to reduce the harmful environmental effects of urea use and runoff from cow effluent.
It was first discovered after Fonterra tests in September last year, but the public and export markets were not told until January.
The Ministry for Primary Industries said yesterday that it did not know where the products went and there would still be products in the supply chain with traces of DCD.
It was found in a "range of products from a range of companies" in the areas where DCD was being used, mainly in the South Island.
The companies would be aware of where the products ended up, but ministry deputy director-general Carol Barnao said: "We don't know exactly where it has gone."
The ministry was telling all export markets for dairy products about the sample results and they were all doing their own DCD assessments.
"There will be some product with DCD which has been in the New Zealand food supply chain," ministry director-general Wayne McNee said, but the levels were so low they were not a food safety concern.
The traces were well below European Commission daily intake levels for DCD.
The minute traces were found in 371 out of almost 2000 samples of milk and milk products made since the middle of last year.
Sampling was targeted at areas where DCD was applied to grass, with the testing focusing on dairy products made during or shortly after DCD was applied to pasture between June and the end of September.
DCD was used on fewer than 5 per cent of dairy farms, mainly from the South Island.
But the last product to show any levels of DCD was made on November 12 last year. DCD had not been used since spring and no traces have been found since then.
"There is no DCD in fresh milk now and the quantities found in products from when DCD was applied were at very low levels," Mr McNee said.
More than 600 samples taken since mid-November showed no traces after the product was withdrawn from the market.
Testing would continue while the ministry sought an internationally accepted level for DCD.
"There will be no DCD applied to pasture from now on. But it might be applied in future, if a minimum standard is put in place," Mr McNee said.
But that could take two to three years.