MICROBIAL POPULATION AND IDENTIFICATION OF MICROORGANISMS ASSOCIATED WITH FERMENTATION SITE AEROSOL ACROSS AKOKO, ONDO

This study investigated the microbial population and identification of microorganisms associated with aerosols at a Garri fermentation site across Akoko, Ondo State. Air and surface samples were collected using sterile Petri dishes exposed for varying time intervals (0–30 min, 1 hr., 1 hr. 30 min, 2 hr.), and cultured on Nutrient Agar (NA), MRS agar, and Sabouraud Dextrose Agar (SDA). Bacterial isolates were characterized using colony morphology, Gram staining, and standard biochemical tests, while fungal isolates were identified based on macroscopic and microscopic characteristics. Antibiotic susceptibility of bacterial isolates was evaluated using the disk diffusion method against twelve commonly used antibiotics. Results revealed that bacterial counts ranged from 6.67 × 10³ to 1.86 × 10⁷ CFU/ml, with the highest counts observed at 2 hr. exposure on MRS agar. Fungal counts on SDA ranged from 2.11 × 10² to 9.72 × 10³ CFU/ml, with surface samples yielding the highest load. Bacterial isolates comprised both Gram-positive and Gram-negative species, including Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Klebsiella cibaria, Proteus mirabilis, Escherichia coli, Enterobacter cloacae, Citrobacter freundii, and lactic acid bacteria such as Lactobacillus plantarum, Lactobacillus fermentum, Lactococcus lactis, Leuconostoc mesenteroides, and Pediococcus acidilactici. Fungal isolates included Byssochlamys fulva, Byssochlamys zygos, Byssochlamys nivea, Cladosporium sphaerospermum, Cryptococcus laurentii, and Geomyces pannorum. Antibiotic susceptibility testing indicated widespread resistance among Gram-positive and Gram-negative isolates to commonly used β-lactams and cephalosporins, while fluoroquinolones (ofloxacin, levofloxacin) and gentamicin showed higher efficacy against most isolates. These findings demonstrate that Garri fermentation sites in Akoko harbor diverse bacterial and fungal aerosols, including potential multidrug-resistant bacteria.