A vitamin check-up for fruit and veg – meet AIBN’s new nanosensor

Imagine scanning an orange with your phone and knowing instantly how fresh it is. Or dipping a strip into your morning juice to check if it’s still packed with Vitamin C. It’s the kind of everyday science that could change how we shop, store and eat fresh food.

Researchers at the Australian Institute for Bioengineering and Nanotechnology (AIBN) have developed a prototype nanosensor that lights up in the presence of Vitamin C – opening the door to faster, cheaper and more accessible ways to test food freshness and quality.

AIBN Group Leader Dr Run Zhang said the project aims to solve a long-standing problem in the food industry.

“Vitamin C is a key measure of nutritional value and shelf-life, but current testing methods are slow, costly and rely on bulky lab equipment,” Dr Zhang said.

“That makes it difficult for farmers and food producers to monitor quality in real time, and it limits the way we can track freshness across the supply chain.”

“We wanted to find a way to take testing out of the lab and make it simple, portable and affordable – while reducing unnecessary food waste.”

The result is a nanosensor – officially called the CoOOH@BSA-FITC nanoprobe – a tiny particle made of cobalt hydroxide (CoOOH) coated with a fluorescent protein that can detect Vitamin C in seconds.

“We coat the particles with a fluorescent protein that is normally switched off. When Vitamin C is present, it breaks down the coating and the glow switches on,” Dr Zhang said.

“The nanosensor glows bright green under a red light when Vitamin C is present. It also changes from brown to yellow under normal light, which means results can be read with the naked eye without any specialised equipment.”

“We’ve tested the nanosensor across a range of products, including fruit juices, whole fruits and plant leaves.”

That flexibility could transform how freshness is measured across agriculture and food production – offering a low-cost alternative to expensive equipment and lab-based testing.

“By having an easy-to-use and cost-effective sensor, farmers could track crop health in real time and know exactly when to harvest for maximum quality,” Dr Zhang said.

“Producers could instantly test how long juice or fruit will last on the shelf, rather than sending samples away to a lab.”

“That same technology could allow supermarkets to run quick, on-the-spot checks before produce reaches consumers.”

This portability also opens the possibility of consumer-friendly devices.

“We imagine a future where families at home can test their own food using simple strips and a smartphone app,” Dr Zhang said.

“That means you could one day scan your fruit bowl and know instantly whether the oranges, kiwifruit or strawberries are still packed with Vitamin C — and even know which banana or apple to eat first.”

Dr Zhang said making freshness testing faster and more accessible could help reduce waste, improve yields and ensure Australians continue to enjoy world-class produce.

“Australia is known globally for clean, high-quality food. A tool like this could give our farmers and producers an edge in global markets, while also helping families cut waste at home.”

The research has been published in Food Chemistry and was co-authored by Dihua Tian, Zexi Zhang, Suzanne Mathews Plavilathundil, Xinyang Tian, Maral Seididamyeh, Mazen Alanazi, Anh Phan, Miaomiao Wu, Jiahua Shi, Yasmina Sultanbawa, Bernard J. Carroll and Run Zhang.

Next steps will involve adapting the sensor technology into low-cost, portable devices and working with industry partners to trial it across different agricultural and food production settings.

AIBN is proud to be solving society’s greatest challenges – one breakthrough at a time.