Validation of HPLC Method for the Assessment of Occurrence of Ochratoxin A in Wheat Grains Sold in Major Markets in Lagos

Abstract

The presence of Ochratoxin A (OTA) in wheat grain is a serious threat to safety of wheat based foodstuff. In the present study, sixty wheat grain samples were collected from six major markets in Lagos for determination of OTA levels using HPLC-FLD utilizing acetonitrile- water-acetic acid (51:47:2 V/V/V) mixture as mobile phase. The limit of Quantitation (LOQ) was 0.47 μg/kg and the average recovery values of OTA for reference material and spiked wheat grain sample ranged from 87.68-107.09%. Twenty-four (40%) wheat grain samples were contaminated with detectable quantity of OTA ranging from 0.40-41.58μg/kg. OTA levels in five samples (20.8%) exceeded the NAFDAC and European Union (EU) permissible limit of 5.0μg/kg. The expanded uncertainty of measurement calculated signifies that the true value is within ±11.00% of the reported results at a confidence level of 95%. Considering that OTA levels in 20.8% of wheat grain samples analyzed are above the permissible limit of 5.0μg/kg, it could be seen as a serious public health threat. Therefore, continuous monitoring and tighter regulation of OTA in cereals is recommended.