Arrest made in case of needles found in fruit sold in Australia.
Officials from the strawberry association said they "have reason to suspect that a disgruntled ex-employee" of Woolworth, the supermarket where numerous affected strawberries were sold, was behind the contamination.
"This has probably been one of the most trying investigations that I've been part of", said Queensland Police Detective Superintendent Jon Wacker, according to Reuters. On Monday, police described their investigation as "far from over".
The court heard Trinh, 50, was working at Berrylicious at Caboolture between September 2 and 5 when she allegedly inserted needles into the fruit.
Queensland Police said it has conducted a national investigation "with multiple government, law enforcement and intelligence agencies" - as well as a police task force in the state.
A Queensland strawberry farm supervisor seeking revenge over a workplace grievance sparked a nationwide crisis by planting needles in fruit, a court has heard.More news: Jose Mourinho still angry at Sergio Aguero for Marouane Fellaini red card
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In response, Australia's government raised the maximum prison term for fruit tampering from 10 to 15 years.
Forty-nine of those brands were Queensland-based, with 186 of the total complaints about needles as the primary contaminant. In Queensland, 77 incidents were reported.
Trinh, a former refugee who arrived in Australia by boat more than two decades ago, will remain in custody until her next hearing later in November. "It was a crisis driven by social media and the only real victims were the strawberry growers, and to some extent other Australian fruit growers and exporters".
Her arrest follows a complex investigation into the alleged contamination of strawberries in Queensland in September. Some supermarket chains in New Zealand also removed Australian product from their stores.
Queensland Strawberry Growers Association vice president Adrian Schultz thanked police for their work.
Panicked state governments had also offered a AU$100,000 (US$72,280) reward for any information that could lead to catching the culprits.