As soon as the Ministry for Primary Industries said there was an issue with Karicare Stage 2, Mrs Nieuwoudt took her 7-month-old son, Eric, off it and swapped to Heinz Nurture.
"We probably won't buy Karicare ever again."
Amrita Sharma went to see her GP to ensure her baby was fine and to see if there was any way of telling if the little one was affected.
Another mother of a 14-month-old said she was angry - all she wanted was straightforward information.
"No one is making this easy for us parents who are concerned about our babies. Why can't the information just be clear and consistent?"
What products are safe?
* All infant formula products EXCEPT Karicare Stage 1 and Karicare Stage 2.
* Fresh dairy products such as milk, cheese and yoghurt.
* Frozen products such as icecream.
* Milk powder.
Getting advice
Healthline: 0800 611 116
Ministry for Primary Industries consumer helpline: 0800 693 721 or mpi.govt.nz
Plunketline: 0800 933 922
Nutricia customer careline: 0800 258 268.