RESEARCH ARTICLE


Degradation of Bacterial Water Quality in Drinking Water after Bottling



Ali Shahryari1, Charlotte D. Smith2, Abolfazl Amini3, *
1 Environmental Health Research Center, School of Health, Golestan University of Medical Sciences, Gorgan, Iran.
2 Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA94720, United States.
3 Laboratory Sciences Research Center, Golestan University of Medical Sciences, Gorgan, Iran.


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Creative Commons License
© 2020 Shahryari et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: (https://creativecommons.org/licenses/by/4.0/legalcode). This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Laboratory Sciences Research Center, Golestan University of Medical Sciences, Gorgan, Iran, Tel: +98 1732454340, E-mail: amini_ab@msn.com


Abstract

Background:

The consumption of bottled water globally, including Iran, has increased tremendously in recent years. This study was designed to assess the bacteriological quality of bottled water and its compliance with the drinking water regulations. In addition, we evaluated bottled waters for the presence of a variety of genera of bacteria and the effect of storage duration on the extent of bacterial contamination.

Methods:

Four hundred samples of bottled water belonging to ten different Iranian brands with various production dates were purchased from supermarkets in Gorgan, Iran, from 2017 to 2018. Bacterial quality of bottled water was assessed using heterotrophic plate count (HPC) followed by usual biochemical tests for identification of bacterial genera, and by the API system.

Results:

The average HPC of bottled water was 9974 colony-forming units per milliliter (CFU/ml). Twelve genera were isolated, among which Bacillus spp. and Escherichia coli were the most and least abundant, respectively. Statistical analysis showed that there was a positive association between water quality and storage duration so that the highest microbial load occurred within the first to third months after bottling. Furthermore, the highest rate of contamination was observed in May when ambient air temperatures commonly reached 40 °C.

Conclusion:

The bacterial quality of bottled water was not according to the standard of drinking water quality. This study demonstrated the variation in bacterial levels after bottling, which indicates the presence of waterborne heterotrophic bacteria, some of which can pose severe health risks to consumers.

Keywords: Bacteria, Drinking water, Heterotrophic plate count, Water Quality, Bottled Water, Escherichia coli.