Federated Farmers says Fonterra should adopt the recommendations made in a review of its handling of the botulism scare and to break down its "fortress Fonterra" mindset.
Shareholders and customers say there was too much confusion when the contamination scare began.
The dairy co-operative's board commissioned the 163-page report after a contamination scare led to its recall of suspect whey protein concentrate in August this year.
Later tests showed the products, which included infant formula, were not tainted with a bacterium that could cause botulism, but the false alarm caused huge losses for some dairy exporters.
In the report released on Tuesday, Fonterra's Independent Inquiry Committee lists 10 primary failures, including insufficient senior oversight, inadequate testing for botulism and a failure to recognise the explosive reputational risk of its food scare.
Federated Farmers dairy vice-chairperson Andrew Hoggard said there was confusion days before he knew if his own child's milk formula was safe. He said communication about food safety needs to be quick and precise.
Although he believes it will be able to put in place the operational changes necessary, he has doubts about the company's ability to overcome the "fortress Fonterra" mindset.
"What I've encountered in the past has been an attitude of no matter what we do we're still going to get lambasted ... so we'll just ignore them and get on with it."
Mr Hoggard says if Fonterra can own up to its mistakes and make them right it will emerge as a better company.
The review has recommended 33 points of action, including improving its risk and crisis management procedures, amending its plant cleaning programmes and making more of an effort to address the "fortress Fonterra" perception.
It said the board needs to set up a risk committee and take greater responsibility for developing relationships with external stakeholders.
Chairman John Wilson promised that Fonterra will do so. He said the findings demonstrate that the company's manufacturing processes and systems are at a "best in class" standard. He says the report endorses much of the management's operational review.
Mr Wilson told Radio New Zealand's Morning Report programme no more staff will go as a result of the contamination scare.
Former managing director of New Zealand Milk Products Gary Romano who publicly represented the company in the early days of the crisis, was one of two people who resigned in the aftermath.
Lincoln University professor of agribusiness Keith Woodford says Fonterra's biggest issue is that its staff need to know how to deal with events which are low probability but big impact, and understand the huge implications of even the smallest mistake.
He says the report revealed managers spent two months arguing over who would pay the $7500 dollar bill for AgResearch's tests, while its customers were oblivious.
