Multiplex flow-through immunoassay formats for screening of mycotoxins in a variety of food matrices

Two multi-analyte flow-through immunoassay formats for rapid detection of mycotoxins in a variety of food matrices (peanut cake, maize, and cassava flour) were developed and evaluated. The selected food matrices are typical staple foods and export products for most low-income communities around the world. The assay formats included gel-based and membrane-based flow-through assays and were based on the principle of indirect enzyme-linked immunosorbent assay. Using the same immunoreagents, the performance characteristics of both assays were compared. To the best of our knowledge, this is the first report on such a comparison. The gel-based format was developed to screen for ochratoxin A, fumonisin B₁, deoxynivalenol, and zearalenone detection at cut-off values of 3, 1,250, 1,000, and 200 μg kg⁻¹, respectively, while the membrane-based format can be used to screen ochratoxin A, aflatoxin B_1, deoxynivalenol, and zearalenone at the following cut-offs: 3, 5, 700, and 175 μg kg⁻¹, respectively. The applicability of these assay formats was demonstrated by evaluating the performance characteristics of both tests through performing multiple experiments on different days. Both assays were further evaluated by analyzing naturally contaminated samples in the laboratory and also in the field under tropical conditions (Cameroon, West Africa). The false-negative rate with both formats was less than 5%, which is in good agreement with Commission Decision 2002/657/EC regarding the performance of analytical methods intended for screening purposes.