Surveying common bacterial contamination in bottled mineral water in Iran

Bottled mineral water is generally considered more pure than tap water in developing countries. Immunocompromised patients and those with co morbid conditions are often offered bottled mineral water since they are believed to be safer. The present study was designed to determine the risk of common bacterial contamination of commercially available bottled mineral water in Iran. For this descriptive study, 68 samples (35 brand named companies) of bottled mineral water were collected from different provinces of Iran. Initially 200 ml of bottled water was filtered with 0.45 micrometer pore (Sartorius label). The filter was divided by sterile pence and scissor to multiple pieces, suspension in nutrient broth and centrifuged. The culture was made by selective media: nutrient agar and broth, dextrose sodium azide agar, yersinia agar, and Clostridium selective agar. The bacterial contaminations were detected after incubation at 42ºC, 35ºC and 25ºC for 24h, 48h and 7 days. Of 68 samples, 41 (60%) showed evidences of contamination with common bacterial, including 15 samples (36%) with Gram-positive spore-forming bacilli, 20 samples (49%) with Gram-positive non-spore-forming bacilli (diphteroids) and 6 samples (15%) with Gram-positive cocci. The marker organisms, i.e. the classic fecal contamination indicators, were not detected in any of the samples. Our results revealed that the use of bottled mineral water in immunocompotent individuals is safe, however, the use of this bottled mineral water in immunocompromised patients should be observed with meticulous precaution. Some of bacteria known as human commensals, contaminate water prior to bottling. It is recommended that bottling, packaging and distribution of mineral water to be carried out under safer processes.