A sensor is being developed by an EU-funded consortium to check for pesticides or bacteria in fruits and vegetables.
The project, called GRACED, is coordinated by the Cyprus Research and Innovation Centre and includes experts from across Europe.
The detector uses light particles to spot traces of pesticide or bacteria. From preparing a sample to detection, the system can give a result in 30 minutes.
It uses laser light to detect chemical or biological analytes. Called a plasmo-photonic bimodal multiplexing sensor, it can spot bacteria or pesticides without having to use chemicals or dyes as a marker.
Current safety checks on fruit and vegetables are made in random batches then sent to a laboratory for testing, a process that can take two to three days to get a result. Analyzing data from these checks can be time consuming and costly.
Expanding previous work
Developers took inspiration from one of their existing sensors that examines water to detect microbiological or chemical contamination with a small number of pesticides.
Project coordinator Alessandro Giusti said the work extends a previous project called WATERSPY.
“In a sense, the two projects are related: bio photonics-based technology to determine contamination in specific matrixes — in WATERSPY, it was drinking water; in GRACED, it can be anything — water used for feeding the plants, or the actual fruits and vegetables themselves. The core technologies, however, are entirely different. Everything is done on a single chip — we are working to detect seven different analytes simultaneously in less than 30 minutes including sample preparation time.”
Running until mid-2024, GRACED will conduct trials in France, Italy, and Hungary, covering different production systems such as conventional open-air farming, novel urban farming, a short agro-ecology value chain and semi-automatic farming. The project received a grant of nearly €5 million ($5.8 million) from Horizon 2020, the EU’s research and innovation program.
The system works by looking at binding of the contaminant to the sensor surface – producing a unique signal when a harmful a constituent is present. Receptors on the sensor surface are tuned to a particular bacteria or chemical so only the analytes of interest are captured along the sensor.
Light travelling in the sensor generates a fully exposed evanescent field over the sensor surface. Here, receptors can recognise the contaminants when a sample passes through. This recognition changes the speed of the laser light and the interference pattern at the output.
This change can be measured and determined against a set of existing values and could give an instant diagnosis for a contaminant expected at the picomolar to attomolar range without the need for amplification.
Other partners include the Consiglio Nazionale Delle Ricerche in Italy; Easy Global Market and Sous Les Fraises from France; Multitel of Belgium; Aristotelio Panepistimio Thessalonikis in Greece; Pilze-Nagy Kereskedelmi Es Szolgaltato of Hungary; and Lumensia Sensors in Spain.
Two other related EU projects
Another EU-backed project is looking at turning mid-infrared (MIR) spectroscopy from existing lab tools to portable detection for chemical and microbial food monitoring.
The work, called PHOTONFOOD, aims to develop novel infrared light sources. The light sources will be combined with waveguide technology and 3D-paper microfluidics.
It will develop a mid-fidelity (MI-FI) device with a low-price range that can be used for daily monitoring, and a medium-price range high-fidelity (HI-FI) device for reference analysis and accreditation.
Efforts will be validated in scenarios for mycotoxins in wheat, nuts, dried fruits and aquaponic-based herbs, as well as pesticides and antibiotics in aquaponic-based herbs.
The project received a grant of almost €5 million ($5.8 million) from Horizon 2020 until the end of 2024. It is coordinated by the Norwegian University of Life Sciences with partners in Germany, Austria, Belgium, Netherlands, Hungary, Spain and Switzerland.
A third EU-funded project is aiming to develop a photonic-based portable optical sensor to allow local food producers and retailers to control food quality and safety.
The work, known as h-ALO, received more than €4 million ($4.6 million) and continues until the end of 2023. It is led by the Consiglio Nazionale Delle Ricerche in Italy with other participants based in Netherlands, Sweden, Germany and Poland.
The aim is high sensitivity, low limit-of-detection and large dynamic range, to detect microbiological and chemical contaminants and to make the system reliable for onsite use by farmers, retailers and non-experts.
A prototype will be validated in a lab by comparing it to commercially available methods and demonstrated onsite in agri-food chains such as aquaponics, craft beer, raw milk and organic honey.
(To sign up for a free subscription to Food Safety News, click here.)