Effect of storage container on the bacteriological quality of water from different sources

Abstract

This research work was carried out to measure the effect of storage container on the bacterial population of water from different sources over a long storage time. Spread plate and other bacteriological techniques were adopted using Nutrient (NA), Salmonella/ Shigella(SSA), MacConkey(MAC), and Thiosulphite citrate bile sucrose (TCBS) agar. Calabash, Glass, Metal and Plastic containers were used to store rain, river, and tap water samples. Sample analysis was taken at time interval of week 0, 1, 3, 5, and 14. In rainwater stored in calabash, total heterotrophic bioload decreased from 9.2 logcfu/ml at week 0 to 5.3 log cfu/ml at week 5 and steady thereafter. Other bioloads in rain water stored in other containers showed similar trend in growth pattern. For river water stored in calabash container, total heterotrophic bioload decreased all through. For river water stored in glass container, it also decreased from 7.0 logcfu/ml at week 0 to 5.8 logcfu/ml at week 1 and was steady thereafter. Other bioloads in river water stored in other containers decreased from week 0 to week 14 at various concentrations. In tap water stored in glass and other containers, all decreased throughout. Several other factors were discovered in this research work to be responsible for the bioload population decrease observed. They include toxins produced during stationary phase as secondary metabolites, acids, nutrient depletion, pH variation, temperature changes. On the statistical analysis (ANOVA), it showed that the containers have significant effect on the bioload of the stored water after 14 weeks storage as plastic recorded the highest bioload change. To this effect people are advised to use plastic container for water storage for a long period. Also people are to filter the water to remove biofilms formed and debris of bacteria that died due to toxins produced. Nutrient depletion and effect of other factors contributed in bacterial population decrease.