But the main reason was that the ministry relied on people feeling safe to approach it with information or fears, he said. It needed to be able to trust that farmers would come forward, and they needed to trust the ministry to protect them.
Personnel on all farms where the disease was present - four owned by the Van Leeuwen Dairy Group near Waimate, one near Maheno in North Otago, and a lifestyle block near Rangiora - had done all that was required by the ministry so it could carry out its work, Mr Smith said.
It did not help anyone to "name and shame" those involved.
Ministry staff gave more details of the multilayered testing and sampling processes than were presented in the previous three public meetings since the outbreak.
"There's a lot of public angst and concern in the farming community," technical liaison officer Victoria Barrell said.
"We're here to alleviate some of that."
The "vast majority" of test results were negative for Mycoplasma bovis.
"That's really good news."
All positive tests were from farms where cattle had direct contact with van Leeuwen livestock. That showed the system was working - there were no unexplained cases, Oamaru veterinarian Hamish Newton said.
If farmers were concerned about their cattle making contact with neighbours' animals, they should decide who was grazing which boundary paddocks when, he said. Where adjacent grazing could not be avoided, an extra fenceline could be installed as a safeguard.
Mr Smith said these events could "either pull apart your community, or pull it together".
"Communication is absolutely critical."
