BACTERIOLOGICAL QUALITY

The safety and microbiological quality of ready-to-eat (RTE) foods are essential to ensuring public health, particularly in institutional environments such as universities, where large populations rely on convenient food options. This study evaluated the bacteriological quality of selected RTE foods sold in restaurants within the University of Benin, Edo State, Nigeria. Food samples analyzed over two weeks included Moi Moi (Bean Pudding), Fried Rice, White Rice, Egusi Soup, and Yam and Plantain Sauce. The Total Viable Bacterial Count (TVC) of the food samples ranged from 2.3 ± 0.30 × 10⁵ cfu/g to 5.1 ± 0.28 × 10⁵ cfu/g in Week 1 and 2.1 ± 0.18 × 10⁵ cfu/g to 4.7 ± 0.30 × 10⁵ cfu/g in Week 2, indicating a significant microbial load that could pose potential health risks. Cultural, morphological, and biochemical analyses were conducted to identify the bacterial contaminants in the food samples. The bacterial isolates identified included Escherichia coli, Bacillus sp., Proteus sp., Citrobacter sp., Staphylococcus sp., and Enterobacter sp. Among these, Staphylococcus sp. was the most prevalent, with the highest percentage occurrence across all food samples. Antibiotic susceptibility testing was performed on the isolates using a panel of commonly used antibiotics, including Cefotaxime, Ampicillin, Ofloxacin, Cefixime, Gentamicin, Levofloxacin, Cefuroxime, Imipenem, Nitrofurantoin, and Nalidixic Acid. The results showed varying levels of resistance and susceptibility, with certain isolates exhibiting multidrug resistance.

This study was conducted to evaluate the bacteriological and sensory qualities of fresh and packaged mixed fruit salad sold along the Ugbowo axis in Benin City, Edo State. Mixed fruit salad samples were collected from various vendors located near the University of Benin, specifically within the Ekosodin and BDPA areas. Upon collection, the samples were securely placed in sterile zip-lock bags and subsequently transported to the laboratory for bacteriological analysis. The bacteriological assessment was performed using cultural techniques, with the identification of isolates conducted through biochemical methods. Additionally, phenotypic virulence properties of the isolates were evaluated, and antimicrobial sensitivity was assessed using the biodisc diffusion method. The results indicated that the heterotrophic bacterial count of mixed fruit salad samples stored in refrigeration and at room temperature for four hours ranged from 2.50 ± 2.12 x 103 cfu/g to 4.08 ± 1.24 x 105 cfu/g. In contrast, samples kept in refrigeration and at room temperature for 24 hours exhibited a range between 1.51 ± 0.20 x 105 cfu/g to 5.70 ± 0.88 x 104 cfu/g. The Staphylococcus aureus count for samples stored in refrigeration and at room temperature for four hours ranged from 1.57 ± 0.78 x 103 cfu/g to 4.50 ± 0.42 x 102 cfu/g, whereas those kept for 24 hours showed a count ranging from 2.50 ± 0.14 x 103 cfu/g to 8.96 ± 0.23 x 104 cfu/g. The coliform bacteria count in mixed fruit salad samples stored for four hours ranged from 2.34 ± 0.21 x 103 cfu/g to 7.20 ± 0.88 x 102 cfu/g, compared to samples stored for 24 hours which exhibited counts ranging from 2.50 ± 0.14 x 103 cfu/g to 8.96 ± 0.23 x 104 cfu/g. The percentage frequency of occurrence of bacterial isolates was as follows: Staphylococcus aureus (12%), Bacillus megaterium (12%), Lactobacillus spp. (12%), Serratia marcescens (6%), Flavobacterium spp. (10%), Enterobacter cloacae (8%), Micrococcus lactis (2%), Bacillus cereus (10%), Staphylococcus warnei (2%), Enterococcus faecium (8%), Bacillus thuringiensis (8%), Salmonella arizonae (4%), Bacillus licheniformis (2%), Klebsiella pneumoniae (2%), and Bacillus subtilis (2%), respectively. The findings of this study underscore the necessity for further research aimed at developing effective strategies for mo itoring and mitigating microbial hazards in ready-to-eat foods, thereby safeguarding consumer health against potential outbreaks associated with antibiotic-resistant bacteria.

Tomato is an economically important fruit in Nigeria. Tomato has a high amount of water which makes them more susceptible to spoilage by the action of various microorganisms. The aim of this study was to achieve the bacteriological quality of tomato fruit puree product preserved and treated with sodium metabisulphite under anaerobic condition. Tomato fruits were purchased at Okoko’s village farm, Ovia North East Local Government Area, Edo state and blended into tomato puree. The tomato puree samples were treated with differing concentrations (0, 0.1, 0.2, 0.3, 0.4 and 0.5g/l) of sodium metabisulphite pasteurized at 65 0C for 15 minutes and then stored for 21 days under anaerobic conditions and analysed at every 7 days interval. The analysis carried out were Total Heterotrophic bacteria, Coliform and Salmonella Shigella count, as well as lycopene content, ascorbic content and changes in pH. From the result, the highest heterotrophic bacteria count was 23±2.8310 4cfu/ml, while the lowest was 1±1.41x10 4cfu/ml from puree sample treated with 0 and 0.5g/l of metabisulphite respectively. The highest lycopene content was 22.01±0.1510 4cfu/ml while the lowest was 7.71±0.15x10 4cfu/ml from puree sample treated with 0 and 0.2g/l of metabisulphite respectively. The identified isolates were: Klebisella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Enterobacter cloacae, Serratia marcescens, Salmonella typhi, Salmonella paratyphi, Escherichia coli, Pseudomonas putida, Proteus vulgaris, Proteus mirabilis and Citrobacter sp. From this study, both pasteurization and preservation by sodium metabisulphite has shown potential as effective ways of prevention against spoilage in tomatoes.