Historical document
Managing micro-organism loading in pistachio nuts to ensure the product is food safe while maintaining integrity (PS10000)
Publication date: August 1, 2012
Delivery Partner: Pistachio Growers of Australia
This is a final research report from Hort Innovation’s historical archives. Please note that as these reports may date back as far as the 1990s, the content and recommendations within them may be superseded by more recent research.
The 2010/11 Pistachio crop was contaminated with a fungal disease, Anthracnose, prior to harvest. The disease had never been recorded as affecting Pistachios and the knowledge of industry was limited. The consequence of the disease was that the crop yield was reduced by at least 50 per cent and the physical appearance and taste of the harvested nuts had been substantially compromised. Most of the nuts were of an inferior quality and not suitable for retail sale.
Pistachio nuts were sold raw or as a roasted and salted product. While there was a quality issue with the 2011 harvest season nuts, it was believed the problems could be overcome in the roasting and salting process. Roasting and salting involved the nuts being dipped into a brine solution for one minute followed by roasting in an oven roaster at 105 ⁰C for around 60 minutes.
Unfortunately, this treatment was not effective in achieving the desired result. After consultation with experts in Australia and pistachio experts in the USA, the problem with the product was identified.
This project addressed these particular issues with the objective of making the product food safe with minimal effect on the overall quality of the product.
After extensive testing and trial work, a technique was developed and utilised during 2012. This technique resulted in nearly the entire 2011 crop being treated and sold to the market.
The project delivered an extremely successful outcome: Australian Pioneer Pistachio Company (APPC) was able to take non saleable nuts and through the process developed through this project produce safe food of an acceptable quality.
If it were not for this project the value of the crop, estimated at around $5,000,000, would have been lost.
The good result of this project enabled adverse quality product to be treated in a similar way in the future.
This historical project was a strategic levy investment in the Hort Innovation Pistachio Fund
© 2026 Horticulture Innovation Australia Limited.
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