Development of an immunochromatographic assay for detection of Aflatoxin B1 in corn and rice

Introduction: Aflatoxin B1 is a toxic contaminant, a threat to human health. Its presence in food was common. Rapid and efficient determination of AFB1 in corn and rice is critical for food safety monitoring. Objectives: To develop a highly sensitive sandwich immunochromatographic assay for the detection of aflatoxin B1, with greater sensitivity than the strip test. Methods: During sample preparation, aflatoxin B1 bound to bovine serum albumin to form AFB1-BSA conjugates, captured by both the anti-BSA antibody on the conjugate pad and the anti-AFB1 antibody on the test line, forming a sandwich structure. Key parameters were optimized to achieve the highest sensitivity of the test strip. Optimal parameters include: saturation of the antibody coating on magnetic nanoparticles, suitable nitrocellulose membrane, and optimal antibody concentration on the test line. Results: Test strips were developed for the rapid detection of aflatoxin B1 in maize and rice. Detection limits: 1.0 µg/L for aflatoxin B1 in the assay buffer and 1.6 µg/L for aflatoxin B1 in spiked maize and rice samples. Repeatability: 5/5 for 5 aflatoxin B1 concentrations analyzed; test strip stability was 6 months when stored at 4°C and 25°C. Conclusion: The immunochromatographic assay provides an efficient and highly sensitive approach for the in situ detection of AFB1 in maize and rice.