All of the samples of infant formula tested by police after being suspected of possible tampering have tested negative for 1080.
The tests came after members of the public reported a number of infant formula tins that appeared to have pin-pricks in the seals.
Police collected the infant formula concerned and tests were carried out that showed the infant formula in those tins was safe.
Assistant Commissioner Mike Bush said the police were of the view that the problems with the seals arose from normal manufacturing or handling issues.
"The parents involved here did the right thing," he said.
An anonymous person sent letters to the chief executive of Fonterra and Federated Farmers threatening to contaminate infant formula with the poison 1080 if the government continued to use it for pest
The Ministry for Primary Industries (MPI), which has overseen testing since the formula threat was made last week, tonight thanked New Zealanders for their continued vigilance in checking products for signs of suspected tampering.
"The parents who reported the suspected tampering are to be commended for immediately reporting this to police," MPI deputy director-general Scott Gallacher said.
"We continue to be confident that New Zealand infant and other formula is just as safe today as it was before this threat was made.
"People should keep using it as they always have, and to continue to be vigilant when buying infant and other formula by checking all product for tampering."
If you have any questions about what to feed your baby, call Plunketline 0800 933 922 or Healthline on 0800 611 116.
For more information go to foodprotection.govt.nz