Molecular identifications, antifungal susceptibility \ profile and detection of toxigenic genes in selected fungal isolates from Cassava flakes (Garri) and public health appraisal

Abstract

The microbial quality of ready-to-eat indigenous foods like garri depends on handling, which could lead to potentially harmful effects on consumer health. This study investigated the prevalence, diversity, antifungal susceptibility profiles, and presence of toxigenic genes in fungal species isolated from garri samples in Uyo, Nigeria. Fungal enumeration revealed higher counts in white garri (max: 5.26 log₁₀ CFU/g) compared to yellow garri (max: 3.24 log₁₀ CFU/g) across four locations. White garri showed an 82% contamination rate versus 67.31% for yellow. Morphological and molecular analysis, including Internal Transcribed Spacer (ITS) region amplification, identified species such as Fusarium spp., Aspergillus spp., Candida tropicalis, and Fusarium proliferatum. Diversity varied by location and garri type, with species like Candida tropicalis and Meyerozyma caribbica being prevalent. Antifungal testing showed Candida tropicalis was susceptible to fluconazole and voriconazole, while Fusarium proliferatum and Aspergillus niger exhibited varied resistance. The amplification of trichodiene synthase (tri5) genes in 100% of Fusarium species and zearalenone polyketide synthase (zea2) genes in 75% indicated a significant potential for mycotoxin production. These findings emphasise the critical need for stringent quality control to mitigate fungal contamination and its associated public health risks in garri.