The NSW Environment Protection Authority (EPA) and the NSW Food Authority have stated that blueberries are safe to eat after further testing did not detect any traces of the banned chemical thiometon.
The presence of thiometon was first raised by Dr Kirsten Benkendorff of Southern Cross University in Coffs Harbour, who reported detecting the substance in punnets of blueberries purchased from supermarkets in 2024. Thiometon, an insecticide deregistered since 1995 due to toxicity, was said to be present in several samples.
The EPA has since contradicted these 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. "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 the detection of thiometon in her research may have been the result of contamination from another spray or product. She noted that her study 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," she explained.
In addition to thiometon, Benkendorff also reported finding relatively high levels of dimethoate. This has coincided with regulatory changes by the Australian Pesticides and Veterinary Medicines Authority (APVMA), which have extended withholding periods for berries treated with dimethoate. Blueberries must now remain unharvested for 14 days after spraying, compared to the previous one-day interval. For raspberries and blackberries, the interval has been extended from seven days to 14.
The residue standards had previously been based on consumption data that was more than 30 years old. Australian berry consumption has increased sharply in recent years, leading to reassessment of chemical use and residue limits in berry production.
Source: The Guardian