Effect of Storage on the Quality of Sachet-Vended Water in the Tamale Metropolis, Ghana

Abstract

Sachet water was introduced in Ghana to provide safe, hygienic and affordable instant drinking water to the general public. The aim of the study was to examine the effect of storage on the quality of sachet-vended water produced in the Tamale Metropolis. Two brands of sachet water were sampled freshly after production (Six packs or bags), transported to the laboratory and analysed. Samples of freshly prepared sachet water were then stored at ambient room temperature (at 27°C), in a refrigerator (at 4°C) and in the sun (at 40°C). Samples from these three storage methods were collected and analysed on a weekly and monthly basis for a period of three months. The physico-chemical parameters were within World Health Organization limits regardless of the mode of storage. The pH of sachet water ranged from 6.69 to 7.89 with a mean of 7.38 ± 0.31. There was no significant difference (p > 0.05) in the physico-chemical parameters for the sachet water under the different storage conditions over the period. The concern however was the low concentration of these major ions, sodium, potassium, total hardness, calcium and magnesium which seem to pose direct health concerns. The counts of total heterotrophic bacteria ranged from 0.0 to 73 cfu/1ml with a mean of 19.16 (SD = 21.61) of the sachet water samples. Total heterotrophic bacteria regrowth was observed on the third week in all brands stored and gradually deceased numerically throughout the study period. Total coliform regrowth ranged from 0.0 to 5 cfu/100 ml. There was significant difference ( p < 0.05) in total coliform counts for sachet water stored under refrigeration and in the sun. The observed regrowth and none or low microbial counts can be attributed to multiple factors such as the effect of temperature, low concentration of nutrients in sachet water, exposure to ultraviolet light rays and permeability of polythene sachet to gases such as carbon dioxide, oxygen and water vapour. Based on the findings of this study, it is recommended that Food and Drugs Authority and Ghana standard Board should ensure minerals concentrations of sachet water are improved to meet the general dietary requirement.