Objective Lipophilic toxins such as okadaic acid (OA) are the main components of diarrheal shellfish poisoning (DSP), which often cause food poisoning incidents and threaten the safety of the shellfish industry and consumer health. Traditional detection methods such as mouse bioassay and liquid chromatography tandem mass spectrometry (LC-MS/MS) are difficult to meet the needs of rapid screening at the grassroots level. This study aims to test a newly developed rapid detection card based on immunofluorescence chromatography (IFC) technology, which can achieve rapid, sensitive, and efficient screening of OA and provide technical support for monitoring departments.

Methods By analyzing the test results of negative and positive samples of Crassostrea gigas, Sinonovacula constricta, and Ruditapes philippinarum using the rapid detection card, the sensitivity, accuracy, and precision of the rapid detection card were analyzed to evaluate its performance in detecting OA in shellfish.The consistency was verified through the comparison experiment with LC-MS/MS.

Results The limit of detection (LOD) and the the limit of quantification (LOQ) of OA in three types of shellfish were 81.23 μg/kg and 191.07 μg/kg, respectively. The average recovery rate evaluated the detection accuracy was (95.4±7.1)%, and the coefficient of variation used to evaluate the detection precision was between 0.03 and 0.11. The false positive and false negative rates are 0%. The linear regression analysis with LC-MS/MS showed a high correlation (R²=0.9578).

Conclusion The IFC detection card has high sensitivity, specificity, stability, and is easy to operate during the detection process. It is suitable for rapid screening on site and has important application value in preventing and controlling shellfish toxin risks, ensuring shellfish food safety, and promoting the healthy development of the shellfish industry.