Microbial analysis and detection of Aflatoxin from Irvingia gabonensis kernels sold in Oyo Town, Oyo State, Nigeria

Abstract

This research work aimed at screening for different microorganisms associated with Irvingia gabonensis var. gabonesis Kernels, its nutritional value and detection of aflatoxins from some of the infested I. gabonensis Kernels sold in Oyo town. A total of 30 different I. gabonensis var. gabonesis Kernels were randomly purchased from six different points in the five major markets in Oyo town and isolation was done on Nutrient agar (NA), McConkey agar, Eosine Methylene Blue Agar (EMB) and Potato Dextrose Agar (PDA) using pour plate method. The isolates were culturally, morphologically and biochemically characterized. The mineral, proximate and aflatoxin detection of the I. gabonensis Kernels with high microbial load and growth of Aspergillus flavus was carried out using standard methods. A total of 25 bacteria and 18 fungal were isolated which include Bacillus spp ., Staphylococcus spp., Aspergillus spp ., Penicillium spp., and yeast. Irvingia gabonensis seeds with growth of A. flavus (OOW1) had the least mineral composition with 5.4% sodium, 20.0 mg/kg vitamin C, 29.4 mg/kg calcium, 0.9 mg/100g iron, 34.4 mg/100 g magnesium and 0.02 mg/100 g zinc. The I. gabonensis Kernels with the growth of A. flavus (OOW1) had the least mineral composition with 5.5% moisture content, 4.2% crude protein, 45.7% crude fat, 9.1% crude fibre and 1.5% total ash. The I. gabonensis Kernels with the growth of A. flavus (OOW4, OOJ6 and OOW1) had aflatoxin level of 3.47, 3.69 and 5.10 ppb, respectively. Irvingia gabonensis seed with high microbial load and growth of A. flavus had low nutritional value making them unsafe for consumption.