Bottled water microbiological quality in Estonia

Water is macro-nutrient without which we can´t live. Nowadays people often prefer to buy bottled water instead of drinking the tap water. Stores are full of different bottled waters and studies have demonstrated that people tend to consider the bottled water to have high quality. The aim of this research was to find out the compliance of bottled water sold in Estonia with the established microbiological normatives. The study included bottled drinking water available in retail stores. A total of 63 bottles of water from 21 different sale items were analysed. These 21 items included also items of gased water and flavoured water („near water“). One bottle of all different sale items (21 bottles) was analysed for E. coli, Enterococcus sp and Pseudomonas aeruginosa (filtration method, cfu/250 ml), and all 63 bottles were analysed for total bacterial count on 22 °C and 37 °C (pour-plate technique, cfu/1ml). The analysis results were compared with local microbiological normatives for bottled drinking water. No E. coli, Enterococcus sp and Pseudomonas aeruginosa were detected in the analyzed waters. Several deviations were noted for total microbial count: 14 bottles out of 63 had bacteria level higher than the established normatives allow, thus 22.22% of bottles were microbiologically contaminated. Results suggest that gasification of bottled water has an inhibitory effect on the total bacterial count. Flavored waters (including sweeteners, richer in bacterial nutrients) did not show higher bacterial counts. Research continues with maintenance experiments (long maintenance effect to the number of total bacterial counts).