Aflatoxin risk management in Texas: test kit approval for maize

Abstract

Five commercially available quantitative test kits were evaluated for their capability to measure naturally contaminated maize samples at 59 µg/kg, 306 µg/kg, and 901 µg/kg aflatoxin levels. The aflatoxin contaminated maize samples, collected during the 2010 Texas corn harvest, were measured using high performance liquid chromatography (HPLC) following Association of Analytical Communities (AOAC) official method 2005.08. Five aflatoxin quantitative test kits approved for measuring aflatoxin contaminated maize containing <100 mg/kg by the United States Department of Agriculture (USDA) Grain Inspection Packers and Stockyard Administration (GIPSA) were evaluated by three analysts who analyzed seven 50 gram samples for each of the three sources of aflatoxin contaminated grain. The relative difference between the HPLC measurements and test kit results were analyzed using an analysis of variance. Significant two-way interactions were observed among the three explanatory variables including analysts, test kit, and aflatoxin level. No significant main effect was observed for analyst. All quantitative test kits performed within GIPSA prescribed performance criteria for the low and medium (59 µg/kg and 306 µg/kg) aflatoxin levels and were approved by the Texas State Chemist to measure aflatoxin contaminated maize as part of the Office of the Texas State Chemist’s (OTSC) aflatoxin risk management program. One test kit failed to perform within extrapolated GIPSA criteria at the 901 µg/kg.