Abstract

The safety of drinking water remains a pressing concern in urban Nigeria, where microbial contamination poses significant public health risks. This study investigated the bacteriological quality of commercially available sachet and bottled water in Port Harcourt metropolis. A total of twenty-four (24) samples; twelve each of sachet water (SW) and bottled water (BW) were randomly purchased and analyzed for total heterotrophic bacterial count, total coliforms, faecal coliforms, and pathogenic bacteria. Descriptive analysis revealed that sachet water samples exhibited a higher microbial load ranging from 105 CFU/mL –8300 CFU/mL  (Mean ± SD: 4376.67 ± 4426.77 CFU/mL;) compared to bottled water which ranged from 101 CFU/mL –460 CFU/mL (Mean ± SD: 280.33 ± 180.69 CFU/mL). However, an independent samples t-test indicated no statistically significant difference in bacterial loads between the two water types (t = 1.954, df ≈ 2.2, p = 0.18). A total of 48 bacteria isolates were identified from sachet water samples, with the most frequent being Escherichia coli (22.9%), Salmonella spp. (22.9%), Aeromonas spp. (12.5%), and Proteus spp. (12.5%). Less frequent isolates included Vibrio cholerae (8.33%), Pseudomonas spp. (8.33%), Acinetobacter spp. (8.33%), and Bacillus spp./B. subtilis (each 2.08%). Bottled water samples also harbored pathogenic bacteria such as E. coli, Salmonella spp., and Vibrio cholerae, albeit at a lower frequency. Statistical analysis (Chi-square) showed no significant association between type of bacteria and the source of water (p = 0.94), suggesting a wide distribution of potential pathogens in both water types. Bacteria profiling per sample indicated multi-species contamination in both water sources. For example, both water products contained E. coli, Salmonella spp., and Aeromonas spp. In addition, SW1 contained Vibrio cholerae, while BW12 harbored Proteus spp., and Bacillus spp. This widespread presence of enteric pathogens especially E. coli and Salmonella spp. raises serious concerns regarding the microbiological safety of these water products. These findings underscore the urgent need for improved surveillance, enforcement of production hygiene standards, and public awareness on water safety. Despite regulatory frameworks, the presence of faecal indicators and waterborne pathogens in both sachet and bottled water points to lapses in water purification processes and post-treatment contamination risks in the supply chain.