Microbes and food 1. Menu - you are what you eat
Bottled waters photo
Picture 1.14a A variety of bottled waters.

1.14 Bottled water
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What's in it?

Bottled water is very popular. Some people believe that some types of water, containing high levels of certain minerals, are actually good for you.

There are two main styles of bottled water, sparkling and still. Sparkling water may be naturally carbonated with carbon dioxide, but the gas is usually added during processing. Microbes do not survive in sparkling water because the dissolved carbon dioxide makes it acid.

Most bottled water comes from springs or deep boreholes, is bottled at source under hygienic conditions and is not treated with chemicals. As a result it can contain harmless, natural water bacteria. These gradually die off in the bottle during storage as they use up the small amount of nutrients. The type of bottled water known as table water can receive various treatments, some of which reduce the numbers of microbes.

How is it produced?

There are basically three types of bottled water.

Natural Mineral Water – must come from a specified underground source, which is protected from pollution and registered with the authorities. It must meet tight microbiological standards, be regularly tested, receive no treatment other than filtration or carbonation and be bottled at source. It must also have a stable chemical composition. Natural Mineral Waters are the highest quality bottled waters.

Spring Water – must come from a single underground source. It must also be bottled at source and comply with microbiological and chemical standards. The only permitted treatments are carbonation and filtration. Spring water does not have to be stable in composition and does not have to be officially recognised prior to marketing.

Table Water – basically any water in a bottle. It can come from more than one source, or not from an underground source at all. Bottled table waters may even come from the public mains or be transported from the source to the bottling plant in tankers. The water may be treated to change its chemical composition or to reduce the number of microbes. Some companies even add mineral salts to the water to taste like spa water.


Natural Mineral Water and Spring Water enter the bottling plant direct from the source through stainless steel pipes. Dedicated filling machinery in special bottling rooms is used. The bottles are capped, labelled and packed in boxes or shrink-wrapped in plastic and loaded on to pallets. Bottles can be made of glass or special types of plastic that do not affect the odour or taste of the water. Both bottles and caps should be sterile. The whole bottling process has to conform to very high hygiene standards and good practice in order to protect the water from contamination. Regular quality checks are carried out at every stage.

Table waters enter the bottling plant either through the mains or in a tanker. Different waters may be blended and various treatments applied such as filtration, ozonation, UV radiation, reverse osmosis or precipitation before they are bottled under similar conditions to Natural Mineral and Spring Waters.

Can it be harmful?

In the UK all bottled waters have to meet the requirements of the Natural Mineral Water, Spring Water and Bottled Drinking Water Regulations (Amendment) Regulations 2003 which ensures that they are safe to drink. Mains water quality is governed by the Water Supply (Water Quality) Regulations 2000.