Abstract
Heterotrophic plate count (HPC) or standard plate count is a standardized method for determining the density of aerobic and facultative anaerobic heterotrophic microorganisms in water. In this study, water samples were analyzed to ascertain the effects of temperature, media, and incubation time in HPC methods of bacterial estimation. The samples were analyzed using the membrane filtration and direct plating methods. No faecal coliform was detected in all the samples and at all temperature. However, some coliforms and heterotrophic bacteria were present in the water samples. The organisms were isolated at 4 °C, 28 °C and 37 °C after 24-72 h. The heterotrophic bacterial isolates include: Enterobacter spp., Staphylococcus aureus, S. epidermidis, Bacillus sphericus, B. cereus, Micrococcus roseus, Pseudomonas aeruginosa and Klebsiella pneumonia. It was observed that yeast extract agar gave a higher heterotrophic plate count at 28 °C while EMB agar yielded the highest total coliform count at 37 °C. The result of the physicochemical analysis showed that the water samples met the World Health Organization (WHO) and Standards Organization of Nigeria (SON) standards for drinking water while the bacteriological quality based on the total coliform count result indicates the need for improvement in the treatment systems.
Highlights
Heterotrophic plate count is a method that measures colony formation on culture media of heterotrophic bacteria in drinking water; it can be used to measure the overall bacteriological quality of drinking water in both public, semipublic and private water systems [1]
Growth on nutrient agar at 4 C with varied incubation periods It was observed that at 4 oC after 24 h incubation, no bacterial growth occurred in all the water samples analysed using both nutrient and yeast extract agar
It can be concluded that all the sachet drinking water samples analyzed were microbiologically safe for drinking as the water samples had no faecal coliform
Summary
Heterotrophic plate count is a method that measures colony formation on culture media of heterotrophic bacteria in drinking water; it can be used to measure the overall bacteriological quality of drinking water in both public, semipublic and private water systems [1]. Shayo et al [4] reported that evaluation of water quality has gained worldwide attention because majority of diseases causing morbidity and mortality are water-related. These occurrences has made infections contracted from contaminated water supplies a leading cause of illness and death worldwide and heterotrophs are the major pathogens of water [3] which includes some enterotoxigenic enterobacteria [5]. Mmuoegbulam et al [6] stated that drinking water is very important in determining the health condition of people in an environment thereby making evaluation of the quality of every public-water pertinent so as to determine their portability
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
