Multiple pieces of glass were found in a punnet of strawberries purchased from Pak'nSave Porirua on Monday night.
In a Facebook post that's gone viral, Adam Reeve said he and a friend were driving to Paraparaumu when they decided to stop and buy some snacks for the road trip.
While they were stuck in traffic, they opened one of their strawberry punnets. Reeve said his friend then yelled "don't eat them" and held up a 1cm piece of glass.
He said they found "lots of fragments" in the punnet and rang the Pak'nSave where they were bought to tell them. They were asked to return the two purchased punnets and were reimbursed.
The thin shards were reportedly similar to lightbulb glass and they were sprinkled amongst the strawberries.
"The glass pieces were various sizes down to tiny specks. Some looked like jelly crystals stuck to the fruit," the Facebook post said.
Reeve claimed his friend started suffering from a sore throat and chest and she was taken to hospital.
They were told by a doctor that because the glass was thin, it was unlikely to do a lot of damage. The woman is now reportedly fine.
Some comments alleged the post was fake, but Reeve said he has "nothing to gain" by posting about the incident and only wanted to help the public.
"If children or elderly people got hold of contaminated strawberries they might eat them and not realise what they're swallowing. Please just take this as a heads up from a fellow member of the public," he said.
Foodstuffs, which owns Pak'nSave, said in a statement it was an isolated incident.
Following an investigation, the Ministry for Primary Industries said a light fitting broke in the store's walk-in produce chiller.
"We are looking into the matter to determine if there is any further risk to the public. If there is, we will take action, including a possible recall," it said in a statement.