Origin of Oranges Can Be Determined

Josh McGillInternational

A Citrus Australia study has used trace elements or isotopes to determine if an orange originated in Australia as opposed to another country. Using the same techniques, researchers can differentiate place of origin of Australian oranges into one of the five Australian growing regions. The first-of-its-kind study was conducted through an Agriculture Victoria Food to Market program.


Citrus Australia noted that increased global demand for high-quality food products has led to premium prices for Australian products in international markets. However, with market growth comes the need for increased traceability and origin verification of products to avoid food fraud, protect brands and ensure continued consumer satisfaction.

Isotopes and trace elements in agricultural products such as fruit are derived from the soil, and differ depending on local geology, climatic and environmental conditions, and agricultural practices. Isotope ratios and trace elements provide a form of laboratory identification at the atomic level, specific to a particular product and region.

The National Isotope and Trace Element (NITE) project collaborated with GNS Science, New Zealand, to analyze trace elements and isotopes of Australian navel oranges to see if their origin could be verified.

“Once you remove all the labels from an orange, you can still find out where it’s from. It’s because of these intrinsic atoms that are infused into the orange. You can’t tamper with them. You can’t add to them or take them away. They’re locked in there, so the orange never lies,” explained Karyne Rogers, senior environmental scientist of GNS Science.

The project was conducted with Australian and competitor country fruit from the harvest seasons of 2021 and 2022.

When using a combination of trace elements and isotopes in this study, Australian oranges were able to be discriminated from other countries at a rate of 97.3%. Oranges from Australian regions could be discriminated from each other at a rate of 92.3%.

“This is helpful to know, that in a crisis when other traceability mechanisms need extra evidence, are not available or have been tampered with, we can show proof to verify the origin of the fruit,” said Nathan Hancock, chief executive officer of Citrus Australia. “In the future, Citrus Australia hopes to build the NITE dataset by adding more data from around the country and more variation on the varieties, too.”

“We may identify growers that are interested in characterization of their own fruit as well as entering into collaborative studies with global partners or peak bodies to add to the dataset and strengthen citrus traceability around the world,” added Hancock.

Limitations of isotope and trace element testing include the expense, time and analytic expertise involved in creating the data points. Encouragingly, oxygen isotope ratios in orange juice have shown particular characterization for Australian oranges in this study. This single test has the potential to be developed as a rapid screen to confirm whether or not fruit is from Australia, with results potentially available within a few days of a crisis occurring.

Source: Citrus Australia

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