The New Zealand Food Safety Authority (NZFSA) plans to call South Island food company Talley's today after a man found a bag of frozen peas he said was made up of nearly 50 percent poisonous black nightshade berries.
It is one of several reported case of contamination of Talley's products.
Humphrey Elton, a father of preschoolers, said he complained to Talley's six months ago after finding the berries in a bag of peas.
The company had simply sent him a $5 cheque to replace the peas and a letter saying the berries were not toxic, Mr Elton said.
NZFSA director of compliance and investigation, Geoff Allen, said today almost 50 percent contamination was unacceptable.
"If the contamination is at that level Talley's need to up their game significantly," he told Radio New Zealand. "We need to be talking to Talley's and actually checking what their quality systems are and what ways that they are looking at to improve their performance."
Talley's should be stipulating maximum levels of weeds and contaminants for the peas which were mostly grown by contractors, Mr Allen said.
Another customer, Anne Anderson, found more than a tablespoon of the berries per cup of Talley's vegetables as she was boiling some frozen peas and corn last week.
And Christchurch man Scott Barnard contacted the NZFSA after finding the berries in a packet of frozen beans he was about to serve his 19-month-old son several weeks ago.
National Poisons Centre spokesman Leo Schep said the black nightshade berries did not kill but were dangerous in large quantities and could cause fever, nausea, diarrhoea, vomiting and abdominal pain.
Talley's said last week the company was starting an immediate review of its processes.
