Purpose  Lipophilic toxins such as Okada acid (OA) are the main components of diarrheal shellfish toxins (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 Pacific oysters, razor clams, and Philippine clams 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 detection limit (LOD) and quantification limit (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 as (95.4±7.1)%, and the coefficient of variation was used to evaluate the detection precision 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 immunofluorescence chromatography 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.