There have been growing concerns about the affecting of shelf life on the quality of bottled drinking water. Six bottled water (BW) brands treated with ozone before bottling as a disinfection were stored at room temperature with lighting for up to one year, thus mimicking typical conditions in retail outlets and supermarkets, and analyzed monthly for one year according to bacteria, algae and Nitrate, In this study there was no significant chemical variability for the new stored BW except the increasing of nitrate concentration. The heterotrophic plate count (HPC) bacteria have been eliminated in the beginning of the new stored BW, in the other side after shelf-life interval of BW, the HPC bacteria and algal population increased concomitant with the decreasing of the nitrates concentration. The diversity of cultured pathogenic bacteria in the bottled mineral water (BMW) was investigated using selective media: Mannitol salt agar, Endo agar base, Difcotm pseudomonas isolation agar and clostridium agar. The pure isolates from these selective media, which showed hemolytic activity on the blood agar media from each brand, were subjected to examination by automated VITEK 2 Compact system (bioMerieux, France). These isolates have been identified as Sphingomonas paucimobilis, Staphylococcus lentus, Pseudomonas stutzeri, and Klebsiella pneumonia ssp., considering the potentially pathogenic features of these strains, their presence in BW may not be desirable. Some algae were detected in some of the examined BW brands as Nostoc, Anabaena and Mastigocoleus that belonged to cyanophyta. The green algae Chlorella and Oocystis were also detected; most of these species have capacity to produce toxins and modify taste and odor accumulated over time. These findings revealed that there is no shelf life for bottled water and prolonged storage can result in a finished product with unpleasant taste and odour as a result of the presence of pathogenic bacterial and algal populations that can affect the immunocompromised.
Key words: Bottled mineral water, Pathogenic bacteria, Ozone, Nitrates
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