A study of microbiological quality of bottled water consumed in Aydin province

The aim of this study was to determine the microbiological quality of bottled spring water sold in Aydın Province. A total of 300 500 ml bottled water samples belonging to 5 different brands were investigated for their Heterotrophic Plate Count (HPC) at 22°C and 37°C, the numbers of Pseudomonas spp. and coliforms. In addition, the prevalences of E. coli and Salmonella spp. were determined. The HPC level of the samples were determined by plating out appropriate dilutions of samples onto Plate Count Agar (PCA) and incubating the plates at 22°C and 37°C?for 2-3 days and 1 day, respectively. The Most Probable Number (MPN) Technique was used to determine coliforms. For determination of E. coli, IMVIC tests were applied to samples which gave positive reaction at MPN technique. Salmonella spp. presence was determined by inoculating each water sample into tetrathionate (TT) and selenite cystine (SC) broths as enrichment. They were then incubated overnight at 37°C and 42°C, respectively. Inoculated broths were subsequently plated for isolation on xylose lysine desoxycholate (XLD) agar, then incubated overnight at 37°C. Suspected colonies were confirmed by biochemical tests. The number of Pseudomonas spp. was determined by plating water samples on CFC supplemented Pseudomonas agar base and incubating for 24-48 hours at 25°C. The results showed that the prevalences of HPC for incubation at 22°C and 37°C were ranging between 46.7% and 61.7%, and 40% and 70%, respectively. The mean numbers of HPC were ranging between 7.94x10 cfu/ml and 4.66x102 cfu/ml for incubation at 22°C, and 9.40x10 cfu/ml and 5.02x102 cfu/ml for incubation at 37°C. No E. coli, Salmonella spp. ve colifroms were determined in any of the bottled spring water samples. The prevalences of Pseudomonas spp. in different brands of bottled water samples were ranging between 18.3% and 35%. The mean numbers of Pseudomonas spp. were ranging between 1.94x10 cfu/ml and 5.63x10 cfu/ml in different brands of bottled water examined. As a result, bottled water samples of 5 different brands did not have E. coli, Salmonella spp. and coliforms which indicated that no fecal contamination occurred during processing and post processing period. However, in some cases, HPC of water samples were found to be high which may have resulted from proliferation during prolonged storage and, to a lesser extent, contamination during processing and post-process period.