Mr Wills said the news that bacterium linked to the potentially fatal disease, botulism, had contaminated some Fonterra whey products had been "an equally unpleasant surprise for New Zealanders too".
"Fonterra is a cooperatively owned company. That means the farmers who supply Fonterra jointly own it and entrust it to turn their cow's milk into high quality products for people the world over to enjoy," he said.
He told Xinhua all the products produced by New Zealand's other dairy processors were safe and unaffected by Fonterra's precautionary recall of this one product line.
However, he said Fonterra needed to prove to its customers that high standards of food production were more than words.
"We must prove that by our deeds and actions."
The products known to be potentially affected were confined to three batches of 38 metric tons of whey protein concentrate manufactured at a Waikato Fonterra plant.
The contamination, by a dirty pipe, occurred in May last year, and testing in March this year indicated a problem. This was confirmed last Wednesday and Fonterra informed the authorities last Friday.