Aflatoxin and Fumonisin Contamination of Sun-Dried Sweet Potato (Ipomoea batatas L.) Chips in Kahama District, Tanzania

Abstract

Sweet potato (Ipomoea batatas L.) is one of the major root and tuber crops of the tropics which can be achieved under a wide range of agro-climates and farming systems. The study was undertaken to determine aflatoxins and fumonisins occurrence in sun-dried sweet potato chips sampled from households in Kahama district in Shinyanga region, Tanzania. A total of 80 sun - dried sweet potato samples were evaluated for aflatoxins (AFB1, AFB2, 1 and 2) and fumonisins (FB1 and FB2) contaminations. High-performance liquid chromatography (HPLC) with fluorescence detection method was used for analysis. The overall percentage of samples which tested positive for aflatoxins was 36% with contamination in ranges from 10.49 µg/kg) to 75.12 µg/kg. The aflatoxin B1 (AFBI) contamination was the most prevalent with concentration of 21.23 μg/kg followed by aflatoxin G1 (AFGI) with concentration of 10.38 μg/kg. Fumonisin B1 (FB1) was the only type of fumonisin detected and had 97.5% of samples contaminated with values ranging from 29.34 – 628.78 mg/kg (mean 44.69 mg/kg). Fumonisin B1 was found to be significantly (p < 0.01) correlated with moisture content. The study has revealed that samples had aflatoxins and fumonisins contamination levels above acceptable levels by East Africa standards and Codex Alimentarius Commission, a joint FAO/WHO Food Standards Program. Efforts in improving post-harvest methods by addressing handling and processing methods is of prime importance in order to minimize risk of aflatoxins and fumonisins contamination of sweet potato chips.