Pure water syndrome: Bacteriological quality of Sachet- packed drinking water sold in Nigeria

Abstract

Water is one of the indispensable resources for the continued existence of all living things including man. Government has failed to adequately provide safe, pipe-borne water for the increasing population in Nigeria and this has encouraged the sale of drinking water by private enterprises that have little knowledge about good manufacturing practices. This study investigated the bacteriological quality of commercial sachet-packed drinking water at point-of-sale in south-western Nigeriawith emphasis on pathogenic bacteria in 108 samples tested, in order to evaluate the contribution of this popular product to the increasing incidence of typhoid fever and related illnesses. Ten-fold serial dilution of water samples and the pour plate technique were used to investigate the presence of Salmonella and indicator coliform Escherichia coli in sachet-packed water samples. Aerobic and total coliforms were also enumerated. Characterization of isolates was by in-vitro cultural, morphologicaland biochemical characteristics. Results showed that 87% of the sachet-packed water samples examined contained Salmonella and/or Escherichia coli, indicative of fecal contamination and inadequate water treatment or no treatment at all. The study also showed that about 65% of the polythene sachets used was not of food-grade quality and imparted polyester taste in the water samples. High aerobic colony counts in theorder of 6.0 log CFU/ml was recorded from 93% of water samples examined. E. coli counts used as indicator of hygiene criteria were present in the range of 98 and 106 cfu/100ml of water sample, while Salmonella counts used as food safety criteria were between 2.12x101 and 2.20x101. These mean values were greater than the international guidelines for drinking water quality. The findings of this study indicate that sachet-packed water samples examined do not meet microbiological standards fordrinking water quality. National surveillance agencies need to monitor and enforce compliance with microbiological safety standards of sachet-packed water being sold to the public.