Department of Microbiology,

Tomatoes (Solanum lycopersicum) are among the most consumed vegetables in Nigeria and constitute a vital component of human diets due to their high nutritional and economic value. This study investigated the microbial profiles of three tomato varieties: Beefsteak, Globe, and Roma sold in a selected market in Benin City, Edo State, Nigeria. Standard microbiological techniques were employed for the isolation, enumeration and identification of both bacterial and fungal contaminants using Nutrient Agar, MacKonkey Agar, Eosin Methylene Blue (EMB) Agar, and Potato Dextrose Agar (PDA). The total viable bacterial counts varied among varieties, with Beefsteak tomatoes exhibiting the highest total aerobic bacterial count (5.0 ± 0.5×10³), Enteric bacterial count (15.0 ± 0.5×10³) and Coliform bacterial count(7.6 ± 0.5 ×10³) followed by Roma and Globe varieties (4.2 ± 0.5×10³, 9.2 ± 0.5×10³, 6.4 ± 0.5 ×10³) and (4.2 ± 0.5 ×10³, 3.2 ± 0.5×10³, 2.6 ± 0.5 ×10³) respectively. Identified bacterial isolates included Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa, while fungal isolates comprised Aspergillus niger, Penicillium expansum, Rhizopus stolonifer, and Fusarium oxysporum. The observed differences in microbial load were attributed to varietal characteristics such as texture, water content, and handling conditions. The results also revealed that poor post-harvest handling, unhygienic market environments, and the use of contaminated wash water contributed significantly to microbial contamination. It is recommended that vendors adopt improved hygiene, proper storage, and temperature control to reduce spoilage and ensure consumer safety.

Microbial analysis in this study was conducted on palm wine samples gotten from five locations in Benin City. The samples were collected from different palm wine bars in the different locations. The microorganisms isolated were identified based on their various morphological, cultural and biochemical characteristics. The microbial analysis of palm wine in this study revealed the presence of diverse microorganisms including Lactobacillus, Acetobacter, Enterobacter, Bacillus, and Staphylococcus specie as well as Saccharomyces cerevisiae, Candida sp., and Aspergillus sp. The highest heterotrophic bacterial count was recorded for Sample A, in which the values were too numerous to count for the first dilution and 12±1.00×10 4cfu/ml for the fourth dilution plated. This was followed by Sample E with values of 1.4±1.00×10 2cfu/ml and 8.0±1.73×10 4cfu/ml for both dilutions plated. The total fungal counts were recorded as 2.06±0.58×10 2cfu/ml and 1.6±1.00×10 4cfu/ml for Sample A, 2.54±1.53×10 2cfu/ml and 8.6±2.08×10 4cfu/ml for Sample B and 4.0±0.81×10 1cfu/ml and 2.6±0.58×10 4cfu/ml for Sample C. Sample D was recorded as 2.26±1.53×10 2cfu/ml and 2.24±0.58×10 5cfu/ml while Sample E was recorded as 2.24±5.69×10 2cfu/ml and 5.4±1.53×10 4cfu/ml. The lowest count was found in Sample B in which the value was 2.6±0.58×10 1cfu/ml for the first dilution plated and no growth was recorded for the 10 4 dilution The presence of Saccharomyces cerevisiae and Lactobacillus spp. with a 100% occurrence in the samples showed their usefulness in the fermentation of the beverage. Some of the organisms isolated such as the coliforms, indicated unhygienic handling of the beverage. It is therefore pertinent that hygiene practices are taken into great considerations in the production and distribution of the beverage.

Biodegradation is a complete degradation process of a polymer through the activity of enzymes produced by microorganisms. The biodegradation process of plastic wastes is the breakdown of complex polymers into simpler oligomers and monomers. The study investigated the biodegradation of low-density polyethylene (LDPE) and high-density polyethylene (HDPE) plastics using fungal species isolated from plastic composted waste soil. Soil samples were collected from Oluku dumpsite and Sawmill sites in Benin City, Nigeria. The samples were subjected to physicochemical analysis to provide baseline environmental characteristics. Fungal isolation was carried out using dilution and pour plate methods on Potato Destrose Agar (PDA). Fungal isolates were identified through cultural and microscopic characterization, followed by PCR sequencing using ITS gene markers. Electrophoresis confirmed successful amplification, and sequencing analysis using NCBI BLAST validated the identity of the fungal strains. The primary fungal isolated included Fusarium oxysporum, Aspergillus flavus and Aspergillus niger. Polyethylene sheets were pretreated by abiotic exposure to sunlight for up to 50 days to simulate natural weathering. The sheets were then cut into fragment and incubated with fungal isolated in mineral salt medium broth at 25oC for varying durations (10-50 days). Data on biodegradation potential were generated by monitoring percentage weight loss and optical density (OD 600).The result of the study revealed that abiotic exposure alone caused minimal weight loss, whereas fungal inoculation significantly enhanced degradation. LDPE exhibited greater degradation than HDPE, consistent with its lower crystallinity and simpler structure. Individual isolates and consortium all had equal degradative activity, meaning any isolate can be used for degradation because there was no significant difference between them. These findings highlight microbial degradation as an eco-friendly strategy for plastic waste management, with scope for further optimization of environmental conditions and fungal consortia to enhance efficiency