A Royal Nut with a Hidden Risk: How Nuclear Science is Making Pistachios Safer to Eat

From the ancient courts of the Queen of Sheba to the supermarket shelves of the modern world, pistachios have held a cherished place in human history. Once reserved exclusively for royalty — legend has it Sheba herself banned ordinary citizens from cultivating them — these vibrant green nuts have long been prized not only for their taste but also for their medicinal uses across Persian, Greek, and Roman civilizations.

Today, pistachios are a global commodity. In 2022 alone, the world produced over one million tonnes of pistachios, with Iran, the United States, and Turkey leading the market. But behind this delicious treat lies a growing concern that threatens both public health and global trade — the presence of aflatoxins, highly toxic and carcinogenic compounds produced by moulds.

The Aflatoxin Threat: Invisible, Deadly, and Growing

Aflatoxins were first discovered in 1960 after an epidemic of turkey deaths in the United Kingdom was traced to contaminated feed. These toxins are produced by fungi such as Aspergillus flavus and Aspergillus parasiticus, which thrive in warm, humid conditions and can infect numerous food crops — especially nuts, maize, and grains.

Pistachios are particularly vulnerable. As the nut ripens, its shell naturally splits open, exposing the kernel to the environment. This makes it susceptible to mould and insect damage, increasing the likelihood of aflatoxin contamination. Post-harvest handling — including improper storage and transport — can further aggravate the issue.

While aflatoxins are invisible to the naked eye, signs of mould may include black or grey lesions on pistachio hulls or kernels. Long-term exposure to these toxins is linked to liver cancer, liver failure, and even immediate death in cases of severe poisoning. Aflatoxins are so potent that their levels in food are tightly regulated worldwide — no more than 10 micrograms per kilogram in pistachios — the equivalent of one grain of sugar in a 100 kg sack.

Traditional Testing: Accurate but Inaccessible

Conventional methods for aflatoxin detection include liquid chromatography and mass spectrometry, which are highly accurate but costly and complex. They require sophisticated lab equipment, trained personnel, and significant time — making them infeasible for many countries, especially during food safety emergencies where rapid detection is critical.

This gap in food safety monitoring is particularly concerning for low-resource countries that are both vulnerable to climate-induced mycotoxin outbreaks and dependent on agriculture and food exports.

The Nuclear Solution: Portable, Powerful, and Precise

To address these challenges, the Food and Agriculture Organization (FAO) and the International Atomic Energy Agency (IAEA) have developed a game-changing nuclear technique that is already transforming how countries detect aflatoxins in pistachios.

At the FAO/IAEA Food Safety and Control Laboratory (FSCL) in Seibersdorf, Austria, scientists engineered a portable sensor system designed for use in low-resource environments. This "lab in a box" uses:

• Electrochemical sensors printed with carbon-based ink on ceramic materials

• A small device called a Potentiostat, which detects tiny electrical signals when aflatoxins are present

• Mobile phone-based data collection for rapid field analysis

This method can detect aflatoxin levels 150 times lower than the permitted threshold, making it ideal for rapid screening, field use, and emergency response.

“It’s faster, cheaper, and doesn’t require an entire lab,” explained Christina Vlachou, Head of FSCL. “That means it can be used in the field, even during emergencies, and in countries that need it most.”

Importantly, this technique has been cross-validated against gold-standard lab testing like liquid chromatography-tandem mass spectrometry (LC-MS/MS), ensuring accuracy and reliability.

Climate Change: A Catalyst for Contamination

As global temperatures rise, so too does the threat posed by mycotoxins like aflatoxins. Climate change is expanding the geographical range of aflatoxin-producing fungi and exacerbating storage challenges. Countries already grappling with food insecurity are likely to suffer the most, both in terms of public health and export restrictions.

The new sensor system provides a crucial line of defense, offering affordable, fast, and scalable solutions to safeguard both food safety and trade.

Atoms4Food and Beyond: A Broader Vision for Food Safety

The pistachio sensor is just one example of the IAEA’s Atoms4Food initiative, which harnesses nuclear science to improve agricultural productivity, nutrition, and food safety globally.

Beyond pistachios, the same technology is now being adapted to detect:

• Fumonisins in maize (another mycotoxin linked to cancer and birth defects)

• Heavy metals like lead in fruit juices

This adaptability means countries can use the same platform to address multiple contaminants across different food categories.

“The IAEA is creating resilient and robust interventions to assist food safety stakeholders in countries around the world,” said Vlachou. “Our goal is to maintain safety and hygiene at required levels to avoid foodborne illnesses.”

What’s Next: Scaling, Training, and Global Access

To ensure broader adoption, the FAO and IAEA are working with member states to expand training, technology transfer, and local implementation. The sensor platform is expected to strengthen early warning systems, support regulatory compliance, and protect consumer health across diverse agricultural markets.

With food safety challenges intensifying due to climate change and globalized trade, innovations like these offer hope and practical solutions. Thanks to nuclear technology, the once royal pistachio can remain a safe, delicious snack — for everyone.