A standard curve was produced by plotting the average threshold cycle (CT) values of duplicates against OTA concentrations with Origin version 8.0 (OriginLab Corporation, Northampton, MA), and used for OTA quantification in the cereal samples. The limit of detection (LOD) was obtained as the estimated OTA concentrations that are euquivalent to the mean blank value plus 3 SD as described by Ueda, ea al27 (link).