It is unlikely the location of the source of last year's Salmonella typhimurium phage type 42 outbreak will ever be pin-pointed, New Zealand Food Safety Authority compliance and investigation director Geoff Allen says.
The outbreak, which caused a spike in salmonella occurrence, mainly in the South Island, including at least 15 cases in Otago, late last year was linked to flour.
Grain may have been contaminated by birds before being made into flour.
The flour believed to be affected was withdrawn from sale and the number of cases dropped, but finding where the contamination occurred had not been easy because there were up to 900 possibilities.
Mr Allen said the authority was trying to use the event to provide farmers and mills with education about suitable storage of grain.
"We'll be working with associations involved in this to get some form of a reminder about this, maybe even look at guidelines," he said.
