Effect of varying storage temperatures and vendor handling practices on the microbiological quality of street sold water in Kumasi Metropolis, Ghana.

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The study assessed the effect of varying storage temperatures and handling practices on the microbiological quality of street sold plastic-bagged sachet drinking water by vendors in the Kumasi Metropolis. Ten different brands of factory-bagged sachet water samples (thirty pieces each), purchased from distributors and vendors were stored at refrigerator (4oC), normal atmospheric (30oC) and room (26.1oC) temperatures over a six month period. Factory-bagged sachet water samples were also bought at random from vendors and the overall hygiene of the unopened bag assessed. Total coliforms, faecal coliforms, Escherichia coli, enterococci, and Salmonella numbers were determined as an index of quality. Bacterial indicator counts (geometric mean per 100ml) varied from 9.00 to 5.56x102 for total coliforms, 4.00 to 3.92x102 for faecal coliforms, 3.00 to 1.75x101 for E. coli, 2.00 to 3.71x102 for enterococci and 3.0 to 5.45 for Salmonella. The microbiological quality of most of the factory-bagged sachet drinking water tested deteriorates if stored at temperatures higher than refrigeration temperatures. Total coliform numbers in sachet water stored over the six month period increased by between 118-182% at normal atmospheric temperatures, 112-154% at room temperatures and decreased by 74% to 92% at refrigeration temperatures. Faecal coliform numbers followed the same trend; increasing by 128-193% at normal, 114-165% at room and decreasing by 79-82% at refrigeration temperatures. Escherichia coli increased by between 102 and 112% and decreased by 59- 93% at normal atmospheric, increased by 33-78% at room and decreased by -25-20% at refrigeration temperatures. Enterococci numbers increased by between 112- 180% at normal atmospheric, 104-147% at room and decreased by 35-96% at refrigeration temperatures. Salmonella decreased by between -28-47% at normal, room and refrigeration temperatures. Vendors handling of plastic-bagged sachet drinking water should be improved in order to avoid potential risk to human health. The numbers were sufficient to affect the WHO Guidelines Standard on drinking water quality and the Ghana EPA guidelines.
A Thesis submitted to the School of Graduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi, in partial fulfilment of the requirements for the Degree of Master of Science in Environmental Science