Angela and Aaron Stevenson's nine-year-old son Mason bit into one of the spiked strawberries at school on Tuesday, while Angela discovered the other needle while cutting up fruit for her 12-month-daughter.
Needles have been found in strawberries sold in Woolworths stores.
Queensland chief health officer Dr Jeannette Young said the contaminated brands came from a farm in south-east Queensland, and were sold to Woolworths, but could also have been distributed to other stores.
Police believe the needles may have been deliberately planted with the perpetrator wanting to cause harm.
"Our investigation is still open, we're not going to get into speculation".
The incident, reported at a supermarket in Gatton, involves the discovery of a thin metal object in a punnet of strawberries. "It wasn't five minutes later they rang back and said it was too late, he'd actually bitten into it", she told ABC radio.
The Queensland Strawberry Growers Association believes a disgruntled farm worker may be responsible but police say they are investigating all aspects of the strawberry transit process.
In a follow-up statement released on Facebook Thursday, the group said the strawberries were seemingly "interfered with between the time they were packed and the time they were purchased".
"At this time [we] have reason to suspect a disgruntled ex-employee may have orchestrated the occurrence, wherein sewing needles were found in a number of strawberries in Queensland and Victoria", the Queensland Strawberry Growers Association said in a statement.More news: Why Meghan Markle has been going on secret 'incognito' trips to London
Queensland Health alerted South Australia's health department Friday afternoon advising Donnybrook-branded strawberries had become the third brand of strawberries linked to the contamination.
'Any strawberries that you are certain are not the brands Berry Licious and Berry Obsession, are safe, ' she confirmed.
One woman wrote on the post: "Sent my 7 year old to school with this brand strawberries this morning".
So far four contaminated punnets have been found - two in Queensland and two in Victoria.
I've purchased strawberries but don't know where they came from. "It makes it hard because you might need to dispose of them earlier, but just cut them up for safety's sake".
It comes after Queensland Health advised for anyone concerned they may have consumed the contaminated strawberries to contact 13 43 25 84 or speak to their GP immediately.
"We have withdrawn Berry Obsession and Berry Licious branded strawberries from sale while this incident is being investigated with our suppliers".
The incident follows an earlier plea from strawberry farmers for consumers to buy more strawberries as the market suffered a glut of the fresh fruit, dropping prices to A$1 (NZ$1.50) or less.
You can report information about crime anonymously to Crime Stoppers, a registered charity and community volunteer organisation, by calling 1800 333 000 or via crimestoppersqld.com.au 24hrs per day.