Diachronic long-term surveillance of bacteriological quality of bottled water in Greece (1995–2010)

The aim of this study is the diachronic surveillance (1995–2010) of the microbiological quality of non-carbonated bottled water sold in Greece. One thousand eight hundred and sixty samples, derived from 29 bottling companies (22 domestic and 7 imported) have been analyzed. The samples were analyzed, using standard methods (ISO) for the detection and enumeration of Total coliforms, Escherichia coli, Enterococcus spp., Pseudomonas aeruginosa and Heterotrophic plate count at 22 °C and 37 °C. 13.0% of the tested samples were characterized as non-comply with human consumption according to Greek legislation, due to the presence of Total coliforms, P. aeruginosa or Enterococcus spp. These microorganisms detected in 9.1%, 6.1% and 1.0% of the samples respectively. The study shows a significant improvement of the quality of the bottled water over time. Also, there was significant difference of microbiological burden among specific brand names and not geographic areas. The present study is one of the very few long-term studies evaluating quality of bottled water in Greece. The study shows a diachronic presence of indicators in bottle water and may help the bottling companies to improve the water quality. The diachronic detection of the bacterial burden in bottled waters highlights the need for systematic and rigorous controls, both in the bottling and during storage and maintenance on the market.