Morphed aflaxotin concentration produced by strain VKMN22 on maize grains inoculated on agar culture.

This study identified and monitored the levels of aflatoxins (B and B) produced by isolate VKMN22 (OP355447) in maize samples sourced from a local shop in Johannesburg, South Africa. Maize samples underwent controlled incubation after initial rinsing, and isolates were identified through morphological and molecular methods. In another experiment, autoclaved maize grains were intentionally re-inoculated with the identified fungal isolate using spore suspension (106 spore/mL), after which 1 g of the contaminated maize sample was inoculated on PDA media and cultured for seven days. The aflatoxin concentrations in the contaminated maize inoculated on culture media was monitored over seven weeks and then measured using liquid chromatography-mass spectroscopy (LC-MS). Results confirmed the successful isolation of strain VKMN22 with accession number OP355447, which consistently produced higher levels of AFB compared to AFB. AF concentrations increased from week one to five, then declined in week six and seven. AFB levels ranged from 594.3 to 9295.33 µg/kg (week 1-5) and then reduced from 5719.67 to 2005 µg/kg in week six and seven), while AFB levels ranged from 4.92 to 901.67 µg/kg (weeks 1-5) and then degraded to 184 µg/kg in week six then 55.33 µg/kg (weeks 6-7). Levene's tests confirmed significantly higher mean concentrations of AFB compared to AFB (p ≤ 0.005). The study emphasizes the importance of consistent biomonitoring for a dynamic understanding of AF contamination, informing accurate prevention and control strategies in agricultural commodities thereby safeguarding food safety.