Rapid Detection of Aspergillus spp. and Quantitative Simultaneous Analysis of Aflatoxins (B1, B2, G1 and G2) in Kenyan Hybrid Maize Cultivars Using FT-IR and LC-ESI-MS/MS Spectro-analysis Techniques

The present study combined Fourier-Transform Infrared Spectroscopy (FT-IR) analysis with high resolution liquid chromatography tandem mass spectroscopy equipped with an electrospray ionization source (LC-ESI-MS/MS) in the screening and quantification of four naturally occurring aflatoxins (AFs) AFB1, AFB2, AFG1 and AFG2 in milled hybrid maize cultivars (n = 171) from selected counties in the Rift-Valley region of Kenya. Samples were extracted in a single-step process using acetonitrile/water 80:20 v/v in 0.5% formic acid without further clean-up steps. Aflatoxins were analyzed in both positive and negative ionization modes using the multi-reaction monitoring (MRM) acquisition process that allowed confirmation and quantification of the aflatoxins in a single run. The MRM mode was utilized for quantitative analysis while qualitative analysis was done using the enhanced product ion mode. Aflatoxin presence was detected in the following ranges and frequencies: AFB1 (0-9.36μg/kg), AFB2 (0-6.62μg/kg), AFG1 (0-7.72μg/kg) and AFG2 (0-9.18μg/kg). Additional mycotoxins recovered included the following; sterigmatocystin (0-8.3μg/kg) and deoxynivalenol (0-7.3μg/kg). In overall, low amounts of aflatoxins were recovered from the milled maize samples with an additional low total aflatoxin content above the stipulated regulatory limit of 10μg/kg. Given that slow continued exposure to aflatoxins (especially in low amounts) has been proven to be a leading cause of various forms of cancer, urgent intervention measures and national surveillance programs ought to be introduced to protect consumers from gradual aflatoxin poisoning emanating from the consumption of contaminated Kenyan maize.