Fonterra says nitrate detected in its milk powder by Chinese officials was not a contamination and could have been sold in New Zealand safely.
The dairy co-operative says 42 tonnes of product was tested and cleared for export in New Zealand, but did not meet testing specifications in China in May.
Fonterra says the product stayed within its control and none of it crossed the border into China.
Fonterra's group director of food safety and quality Ian Palliser told Checkpoint Fonterra doesn't know why nitrate was detected in China.
He says Fonterra will not be changing its testing regime.
Mr Palliser says many countries Fonterra exports to have different restrictions and testing regimes.
The office of the Primary Industries Minister meanwhile says he was not notified at the time of the new contamination scare, because it was treated as business as usual.
Nathan Guy was not available to talk to Radio New Zealand, but a spokesperson says ministers were not informed because there are a large number of similar cases every year.
The spokesperson says it is not unusual for there to be issues of quality assurance around certain products, but most of these have no impact on consumers.
Explanation needed - Labour
The Labour Party says the Primary Industries Minister needs to front up about the new scare and that high nitrate levels showed up in whole-fat milk powder, in May.
Its Primary Industries spokesperson Damian O'Connor says the minister owes an explanation to the dairy industry.
He says it's important that all in the dairy industry are aware of problems so they can share information, and minimise the impact on consumers.
Mr O'Connor says New Zealand needs a higher quality testing regime, like that in China.
Fonterra announced on 3 August that some of its products could contain a bacteria that can cause botulism.