Effects of steeping on fungal contamination and diversity in achi (Barchystegia eurycoma) seeds sold in some selected markets in Lagos state, Nigeria

Abstract

Achi (Brachystegia eurycoma) seeds are widely used as a thickening agent in traditional Nigerian cuisine. However, the processing methods used for achi seeds can lead to fungal contamination, posing considerable health risks to consumers. This study aims to investigate the effect of water steeping on fungal species contaminating achi seeds sold in some selected markets in Lagos, Nigeria. The achi seeds were steeped by soaking them in water at 37 °C for two days, and the moisture content was subsequently determined. The isolated fungal species were identified using both morphological and molecular techniques. Our findings show that the moisture content (37.82—51.64%) of the steeped achi seeds was higher than that of the unsteeped achi seeds (8.32—15.73%). Seven fungal species were recovered from the achi seeds, including six Aspergillus spp. (A. aculeatus, A. flavus, A. fumigatus, A. niger, A. japonicus, and A. oryzae), along with Rhizopus microsporus. Notably, the steeped samples were found to contain all the seven fungal species whereas the unsteeped achi were contaminated with just four fungal species, namely A. aculeatus, A. flavus, A. fumigatus, and A. niger. Additionally, the steeped achi seeds showed a higher fungal load (4.92 × 103—5.50 × 103 CFU/g) compared to the unsteeped samples (3.39 × 103—5.33 × 103 CFU/g). This current study indicates that steeping increases fungal contamination and diversity in achi seeds, raising concerns about food safety.