Is bottled water susceptible to contamination?
Bottled mineral water, a popular choice for many, comes with an expiration date. Contrary to popular belief, this date doesn't indicate the water itself going bad, but rather the optimal period for maintaining safe quality and optimal taste based on the packaging.
The plastic bottle, usually PET, gradually degrades over time, potentially leaching chemicals such as BPA and antimony into the water. This can affect safety and taste, especially when exposed to heat or sunlight. Additionally, the plastic can absorb odors or impart a plastic flavor to the water, diminishing its freshness.
Proper storage plays a crucial role in maintaining the water's taste and quality. Cool, dark, and dry storage conditions help preserve the bottle's integrity and prevent chemical leaching. On the other hand, exposure to heat or direct sunlight accelerates plastic degradation and chemical leaching, leading to changes in taste and potentially harmful chemical buildup.
Bottled water kept for long periods in poor storage conditions may taste stale, develop a plastic odor, or lose carbonation if carbonated. However, it's essential to note that the water itself does not spoil or support microbial growth inside sealed commercial bottles. Mishandling or reusing bottles without proper cleaning can introduce contamination.
Sparkling water, in particular, benefits from carbonic acid, which helps inhibit the formation of microorganisms, potentially extending its shelf life. However, PET bottles, due to their less tight seals, may allow for the escape of carbonic acid and the passage of acetaldehyde, a colorless chemical compound that is harmless but disturbing in taste.
The EU requires a minimum shelf life for bottled mineral water, with many manufacturers specifying about 2 years. While this is mostly for maintaining taste and perception, not for ensuring safety, an unopened bottle of bottled mineral water will not activate microorganisms.
In contrast, glass bottles offer reliable protection against loss of taste for bottled mineral water due to their tight seals. Glass bottles are, therefore, advantageous for maintaining the taste of sparkling water.
In conclusion, the expiration date on bottled water indicates the best period for maintaining safe quality and optimal taste based on the packaging, not water spoilage. Proper storage significantly helps maintain the water’s palatability and safety. And while the expiration date doesn't necessarily mean the water has gone bad, it's always best to err on the side of caution and consume the water before its expiration date for the best taste experience.
[1] Food and Water Watch. (2020). The Truth About Bottled Water. Retrieved from https://www.foodandwaterwatch.org/water/bottled-water/
[2] Environmental Working Group. (2021). Bottled Water Quality Database. Retrieved from https://www.ewg.org/bottledwater/
[3] European Commission. (2018). Bottled Water. Retrieved from https://ec.europa.eu/food/safety/labelling_nutrition/labelling/specific-foods/bottled-water_en
[4] Consumer Reports. (2019). Bottled Water Quality. Retrieved from https://www.consumerreports.org/water-quality/bottled-water-quality-testing-results/
