Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering
Paging:
Volume 22 (1987) nr. 4 pages 357-367
Year:
1987-05
Contents:
The bacterial quality of a total of 204 water samples representing 22 brands of bottled waters (both domestic and imported) obtained from retail outlets in the Cincinnati, Ohio, area was examined using the heterotrophic plate count and the total coliform multiple-tube fermentation and membrane filtration techniques. It was found after 48 hr at 35°C that 27 percent of the samples of domestic bottled waters examined had bacterial heterotrophic plate counts in excess of 500 colony-forming units (CFU) per ml, with the majority of these in the 1000 to 100,000 range, whereas 73 percent contained fewer than 500 bacteria as CFU per ml. All of the three imported brands had bacterial levels below 500 CFU per ml. Extended incubation of bacterial plates at room temperature for seven days resulted in a 17.3 percent increase in bacterial counts in excess of 500 CFU per ml, with the greatest predominance of recovery occurring in the 1000 to 100,000 range. No total coliforms were detected in any bottled vater examined, but pigmented non-coliform bacteria vere found to constitute a major portion of the bacterial flora in bottled vater with high bacterial numbers (i.e., > 500 CFU per ml). It vas concluded that the bacterial standards for bottled vaters should be based upon not only the total coliform determination, but also upon a bacterial heterotrophic plate count of no more than 500 CFU per ml after protracted incubation times longer than 48 hr.