Low-cost paper-based sensors modified with curcumin for the detection of ochratoxin a in beverages

Detection of mycotoxins in food is essential due to their potential harm to human and animal health. However, developing affordable and rapid methods for their detection, particularly with the necessary selectivity to differentiate between various mycotoxins, remains a challenge. Herein, we present low-cost paper-based sensing platforms modified with curcumin, a natural polyphenolic compound, for the electrochemical and optical detection of ochratoxin A (OTA). By exploiting the fluorescence quenching effect of OTA on curcumin through Förster energy transfer, we successfully conducted optical detection with LODs of 0.09 ng mL⁻¹ and a linear range of 0.5 to 15 ng mL⁻¹. Additionally, by using electrochemical impedance spectroscopy and a portable instrument, we detected OTA with a limit of detection (LOD) as low as 0.045 ng mL⁻¹. These sensitivity levels meet the requirements established by food regulatory agencies for monitoring food quality in relation to OTA contamination. Our curcumin-modified paper-based sensors offer a compelling combination of simplicity in manufacturing and cost-effectiveness, underscoring their potential for routine food quality monitoring, especially concerning ochratoxin A.