There are numerous debates worldwide whether bottled mineral water can spoil or go bad and what the correct shelf life of an unopened bottle of mineral water is. At present, food and health authorities worldwide have not placed a stringent set of guidelines relating to the shelf life of still bottled mineral water.
In South Africa bottled mineral water has a best before date indicated on the packaging. Still bottled mineral water has a best before date of two years after the mineral water has been bottled, whereas sparkling mineral water has a reduced shelf life. This is due to the carbon dioxide in the mineral water that makes the water gassy or sparkling. When a bottle of sparkling mineral water stands for a long time, the carbon dioxide will slowly break down and escape through a plastic bottle.
As a general rule, all unopened bottled mineral water should be stored in a cool dark area away from direct sunlight. Many people advise that one should drink mineral water before the best before date for the freshest results. Mineral water bottles should also be stored away from chemicals and other items that omit strong odours that may be drawn into the bottled water and so effect the taste and quality of the water.
The quality of the mineral water after an extended shelf life will depend on a number of factors which include the quality of the water before it was bottled. For this reason mineral water undergoes numerous tests before the water is even extracted from the source. These tests ensure that the mineral water is free from any fungi or bacteria that may cause diseases as well as any other pollutants that may be harmful to people.
The manner in which the mineral water is stored before being bottled as well as the quality of the filtration methods used if necessary will also influence the shelf life of bottled mineral water.