My Ut Trinh appeared in Brisbane Magistrates Court on Monday, charged with seven counts of contamination of goods with intent to cause economic loss.

The court heard Trinh, 50, was working at Berrylicious at Caboolture between September 2 and 5 when she allegedly inserted needles into the fruit.

It will be alleged DNA matching Trinh's was found on one of the needles.

The first needle was discovered on September 9 when a man bit into a contaminated strawberry he bought at a supermarket, and Trinh almost immediately became a person of interest to police, the court heard.

As more needles were discovered around the country - with many believed to have been planted by copycats - strawberries were stripped from shelves.

Growers like Trinh's boss suffered massive financial losses as they were forced to destroy crops.

Magistrate Christine Roney said the Crown was alleging Trinh was "motivated by spite or revenge" over a workplace grievance, but said she would not consider granting bail until the reasons for the retribution became clearer.

Trinh's lawyer Michael Cridland withdrew the bail application, but said his client was not an unacceptable flight risk.

He said Trinh, a former refugee who arrived in Australia by boat more than two decades ago, had strong family ties to Brisbane.

Mr Cridland said Trinh, who required a Vietnamese interpreter in court, was an Australian citizen and had complied with all police requirements thus far.

He said any risk of flight could be mitigated by "suitable firm conditions" like forfeiting her passport.

Trinh was remanded in custody until November 22. She faces up to 10 years' jail if convicted.

Earlier on Monday, Detective John Walker said the investigation involved almost every state and jurisdiction in the country.

He said 230 incidents were ultimately reported nationwide, affecting 68 strawberry brands.

"The investigation is ongoing and further investigative strategies are being undertaken," he told reporters.

Australian Associated Press