No traces of banned chemical thiometon found in blueberries,...

The NSW Environment Protection Authority and the NSW Food Authority have said blueberries are safe to eat after further testing did not detect any traces of banned chemical thiometon.

The presence of thiometon was first flagged by a researcher, Dr Kirsten Benkendorff at Southern Cross University in Coffs Harbour, after she tested punnets of blueberries bought at local supermarkets in 2024.

Thiometon, an insecticide that has not been registered for use since 1995 due to its toxicity, was present in a number of samples, she said.

The EPA, however, has contradicted the findings.

“Data from industry testing provider FreshTest for the same testing period as the research project – October and November 2024 – showed no evidence of thiometon residue on any berries tested,” the EPA and the Food Authority said in a joint statement on Friday.

“Additionally, a review of the 2024 research found the methodology and analysis used were not accredited for testing fresh fruit such as berries, and therefore the results are unreliable.”

Benkendorff said her detection of the thiometon may have been due to contamination of another spray or product used in horticulture.

She said she used a “low level detection pesticide suite” at a nationally accredited laboratory capable of detecting 157 environmental contaminants, including thiometon.

“This method can detect many pesticides at levels 100x lower than the standard supermarket testing, as well as picking up some unregistered chemicals that they don’t test for,” Benkendorff said.

Benkendorff’s other finding of relatively high levels of residues of dimethoate has coincided with swift action by Australian Pesticides and Veterinary Medicines Authority (APVMA) to extend the time between spraying berries with the commonly used insecticide to 14 days.

Previously, blueberries could be picked one day after spraying and raspberries and blackberries within seven days.

The residue limits were based on 30-year-old consumption data, and Australians have dramatically increased their consumption of berries.

Dimethoate, an organophosphate pesticide used for the control of fruit fly, was banned in the European Union in 2019 amid concerns about its human health impacts. It has been associated with neurological disorders and can cause skin irritations.

Benkendorff found that while the blueberry samples were within the legal residue limits for dimethoate, the levels on some were high enough that both children and adults could exceed the acceptable daily intake (ADI) by eating less than a standard 125g punnet.

Benkendorff’s findings, first reported by the ABC in September, have led to a flurry of activity by the regulators. The APVMA insisted that it had already started a review of dimethoate use on berries after Food Standards Australia and New Zealand (FSANZ) alerted them to increased blueberry consumption in Australia earlier this year.

As the ABC reported, the food regulator had conducted a survey in 2024, which revealed that consumption of berries in Australia had increased between 285 and 962%.