Validation of a New Rapid Test for Vitamin A in Premix and Fortified Flour

Abstract

Objectives: Wheat flour is a possible food vehicle for vitamin A fortification. Recently a new portable rapid test (iCheckTM FLUORO) has been available to measure vitamin A in various fortified food samples such as premix and flour. In this study the performance of the rapid test was compared with the reference vitamin A method. Methods: For the method comparison, 58 fortified wheat flour samples were analyzed with both the new rapid test method and the reference HPLC (high performance liquid chromatography) vitamin A method. Results: The coefficient of variation of 5 replicate measurements with the new method was 1.8% and 3.2% for the premix and wheat flour samples, respectively. Vitamin A levels in the flour samples were between 0.5 - 63.4 mg RE/kg. The Spearman coefficient for iCheckTM FLUORO vs. HPLC is 0.9763. The Bland-Altman analysis shows that HPLC and iCheckTM FLUORO results differ on average by as low as 0.1 mg RE/kg and 98% of samples were in range. Conclusions: The new iCheck FLUORO method shows a good agreement with HPLC and a good reproducibility for flour. Intrinsic flour fluorescence causes difficulties when low levels of vitamin A are analysed resulting currently in a higher detection limit of 1 mg RE/kg. Because of its simplicity, speed and accuracy the method is well suited for quality control of fortified flour samples.