Simultaneous Rapid Detection of Aflatoxin B1 and Ochratoxin A in Spices Using Lateral Flow Immuno-Chromatographic Assay

Abstract

Spices are susceptible to contamination by aflatoxin B₁ (AFB₁) and ochratoxin A (OTA), which are both mycotoxins with high toxicity and carcinogenicity. In this study, we aimed to develop an immuno-chromatographic strip test for the simultaneous quantification of AFB₁ and OTA in spices by spraying the coupled antigens AFB₁-ovalbumin (AFB₁-OVA) and OTA-ovalbumin (OTA-OVA) on a nitrocellulose membrane. The test strip had high sensitivity, good specificity, and strong stability. The detection limits of these two mycotoxins in Chinese prickly ash, pepper, chili, cinnamon, and aniseed were 5 μg/kg. The false positivity rate was 2%, and the false negativity rate was 0%. The maximum coefficient of variation was 4.28% between batches and 5.72% within batches. The average recovery rates of AFB₁ and OTA in spices were 81.2-113.7% and 82.2-118.6%, respectively, and the relative standard deviation (RSD) was <10%. The actual sample detection was consistent with high performance liquid chromatography analysis results. Therefore, the immuno-chromatographic test strips developed in this study can be used for the on-site simultaneous detection of AFB₁ and OTA in spices. This method would allow the relevant regulatory agencies to strengthen supervision in an effort to reduce the possible human health hazards of such contaminated spices.