Fonterra has found a faulty pump was the most likely cause of E.Coli bacteria contaminating some cream products in January.
Fonterra Brands New Zealand launched a recall of 8700 bottles of fresh cream distributed in the upper North Island after tests indicated some may have been contaminated.
The company is still waiting for the final results of detailed testing.
However, Fonterra Brands managing director Peter McClure said results so far have shown no trace of the dangerous forms of E.Coli in any cream products.
He said the company has identified and fixed the likely cause of the contamination in the plant that processed the cream.
Mr McClure said it had been found that a pump which pumps the cleaning fluid through the pipes had slowly dropped in terms of the flow rate that was passing through it from about 8000 litres per minute down to about 5000.
He said the company thought that the cleaning fluid was not doing the job it was meant to because of the drop in flow rate and that E.Coli may have formed in some cream residue that was not being properly flushed through the system.
Mr McClure said Fonterra has improved the flow rate back to where it should be, as well as putting an alarm on the pump so that if it drops below the required flow rate the alarm will go off.
He said the company has also checked similar equipment elsewhere in its processing systems.