Researchers developed a low-cost electrochemical sensor that rapidly detects trace antibiotic residues in milk, supporting food safety, dairy quality monitoring and public health.
Researchers have developed a highly sensitive electrochemical sensor capable of detecting trace levels of veterinary antibiotic residues in milk, offering a rapid and cost-effective approach to food safety monitoring. The study focuses on detecting ceftiofur sodium, a commonly used veterinary antibiotic whose residues can contribute to antimicrobial resistance if they enter the food supply.
The sensor combines rice straw-derived biochar with a conductive polymer and molecularly imprinted polymers (MIPs) to create a highly selective sensing platform. Biochar, produced from agricultural waste, provides a sustainable and inexpensive support material, while the molecularly imprinted polymer forms recognition sites that match the shape and chemical properties of ceftiofur molecules. This enables the sensor to distinguish the target antibiotic from other compounds commonly found in milk.
To fabricate the device, researchers synthesized mesoporous biochar through nitrogen-assisted high-temperature pyrolysis and modified it with citric acid to enhance its surface chemistry. They then electropolymerized a conductive polymer around the antibiotic template. After removing the template molecules, the remaining cavities selectively captured ceftiofur, producing an electrical signal proportional to its concentration.
Laboratory tests showed that the sensor achieved a detection limit of 0.03 nanograms per millilitre, while maintaining excellent selectivity and sensitivity. It demonstrated minimal interference from structurally related antibiotics and common milk components such as proteins, vitamins and minerals. Validation using raw, commercial and locally sourced milk samples produced results consistent with liquid chromatography-mass spectrometry, confirming its analytical accuracy. Storage tests also indicated that the sensor retained approximately 90% of its initial performance after more than one month under cold storage.
Researchers believe the technology could strengthen dairy quality assurance by providing portable, low-cost, on-site testing throughout the milk supply chain. Future work will focus on integrating the sensor into portable microfluidic devices and test strips for routine food safety screening and broader detection of veterinary antibiotic residues.
