More than six months after someone threatened to poison infant formula with 1080, police say they are still looking for the person - or people - responsible.
In November, letters containing a concentrated form of 1080 were sent to Fonterra and Federated Farmers, with a threat to contaminate infant formula with it unless the poison's use in pest control in New Zealand stopped.
Police Deputy Commissioner Mike Clement said the investigation was still live and the police were pursuing several lines of inquiry.
"Up to 35 staff, depending on requirements, are involved with the investigation, which remains fully focussed on identifying the person or persons responsible for the threat.
"We continue to urge the public to be vigilant and report anything suspicious, and we continue to appeal for anyone with information relevant to the enquiry to contact police," he said in a statement.
The Ministry for Primary Industries (MPI) said more than 120,000 samples of raw milk and infant formula have now been tested and no 1080 has been detected.
"A police assessment of the threat has determined that the risk of release of contaminated product is low," it said in a statement.
"Nevertheless, current retail measures will remain in place for a period of time. What this period of time will be is still being worked through with manufacturers and retailers."
Both Countdown and Foodstuffs said all security measures, including having a staff member watch the shelves where the products were kept, were still in place.
A Countdown spokesperson said it was still in regular contact with the police and MPI regarding the threat.