Detection of aflatoxins, trichothecenes, ochratoxin a and zearalenone by test strip enzyme immunoassay: A rapid method for screening cereals for mycotoxins

The development of test strip enzyme immunoassays (EIA) for the rapid detection of a number of mycotoxins is described. Monoclonal or polyclonal antibodies against aflatoxin B1 (AFB1), aflatoxin M1 (AFM1), ochratoxin A (OA), T‐2 toxin, diacetoxyscirpenol (DAS), 3‐acetyldeoxynivalenol (3‐AcDON), roridin A (RA) and zearalenone (ZEA) were immobilized on a nylon membrane. Using the corresponding toxin‐horseradish peroxidase conjugate in a direct competitive assay, dot colour development of toxinpositive test strips was visually discernible from that of the negative control. The results of the visual evaluation were compared with that of instrumental reflectance measurements of the test strips. The visual detection limits of the test strip assays for mycotoxins were at 0.6 ng ml−1 (AFB1) 0.2 ng ml−1 (AFM1), 2.0 ng ml−1 (OA), 1.0 ng ml−1(T‐2 toxin), 0.2 ng ml−1 (DAS), 10.0 ng ml−1 (3‐AcDON), 15.0 ng ml−1 (RA), and 5.0 ppb (ZEA) respectively. Utilizing a simple extraction procedure, AFB1, OA, T‐2 toxin, and ZEA in spiked corn samples were detected by test strip EIA at levels of 15 ng g−1, 100 ng g−1, 20 ng g−1 and 80 ng g−1 respectively.