COMPARATIVE EVALUATION OF AFLATOXIN SAFETY AND FTIR-BASED DETECTION OF ADULTERATION IN LOCALLY PROCESSED POWDERED GARLIC AND TURMERIC SOLD IN SELECTED MARKETS IN KADUNA NORTH, NIGERIA.

Garlic and turmeric are widely used spices that may be susceptible to quality deterioration and adulteration during processing, handling and storage. This study evaluated the moisture content, ash content and total aflatoxin concentration and assessed possible adulteration using Fourier Transform Infrared (FTIR) spectroscopy of locally processed powdered garlic and turmeric sold in selected markets in Kaduna North, Nigeria. Powdered garlic and turmeric samples were collected from three markets: Kawo, Unguwar Rimi and Central Market. Samples from three vendors in each market were combined to form composite samples. Raw samples were also collected and processed in two forms (Peeled and unpeeled) to serve as the control. Moisture and ash contents were determined using standard AOAC procedures, while total aflatoxin concentration was determined using competitive enzyme-linked immunosorbent assay (ELISA). FTIR spectra were obtained over the range of 4000–650 cm⁻¹ and compared among market-processed samples, controls and selected potential adulterants. The moisture contents of garlic and turmeric ranged from 3.45 to 4.69% and 5.27 to 5.89%, respectively, while the corresponding ash contents ranged from 4.59 to 5.24% and 3.38 to 4.68% for garlic and turmeric respectively. Total aflatoxin concentrations ranged from 0.052 to 0.229µg/kg for garlic and 0.251 to 0.678µg/kg for turmeric, with all values falling below the EU/WHO/NAFDAC 10 µg/kg regulatory limits. FTIR spectral comparisons revealed differences between market-processed samples and controls, while similarities between market-processed garlic and selected plant-based adulterants and between market-processed turmeric and maize flour/cornstarch suggesting possible adulteration. The findings indicate that although the investigated samples had aflatoxin concentrations below the regulatory limit and therefore, are safe for consumption based on aflatoxin levels, differences in FTIR spectral profiles highlight the need for continued monitoring of the quality and authenticity of locally processed powdered spices. FTIR shows potential as a rapid screening technique for detecting possible adulteration in powdered garlic and turmeric