Peanut- and Corn-Based Media Reveal Phenotypic, Metabolomic, and Toxigenic Plasticity in Aspergillus flavus

Aspergillus flavus is a significant foodborne pathogen and aflatoxin producer that causes invasive aspergillosis. Its isolation has limitations due to obstacles in providing optimal physicochemical conditions in conventional media. The study aimed to design peanut- and corn-based media to explore Aspergillus flavus’s isolation efficacy, sporulation, major aflatoxins and metabolic profile compared to conventional media. PSM and CSM supported robust colony development (8.5 cm diameter) and dense sporulation. HMDB-based metabolomic profiling revealed distinct metabolic signatures and enhanced production of diverse primary and secondary metabolites in PSM- and CSM-grown A. flavus compared with conventional media, with KEGG pathway enrichment highlighting significant shifts in carbohydrate, amino acid, and lipid metabolism and nucleotide, cofactor, and vitamin biosynthesis, along with aromatic compound degradation. Among the four major aflatoxins, AFB1 was the only detected toxin with different concentrations in the media (Kruskal–Wallis H = 17.86, df = 3, p < 0.001): PSM (679.52 µg/kg), SDA (451.52 µg/kg), CSM (343.19 µg/kg), and PDA (22.08 µg/kg). Compared to PSM, PDA produced ~30-fold less AFB1 toxin (p < 0.0001). Altogether, PSM and CSM are potential candidate media for isolating A. flavus and characterizing its metabolic and toxigenic traits, advancing research in clinical mycology, food safety, and mycotoxin biology.