Contaminants of Bottled Water

The contaminants described here refer to visible foreign objects that float in the water and are unappealing at best and may be harmful to one’s health at worst. The floating appearance has led to the descriptive (if not crude) layman’s term of “floaters” to describe any foreign object that is visibl e in any beverage, including bottled water.

Contaminants may be inorganic or organic in origin, and although visible to the naked eye, microscopy is normally required to view their detailed structure. Thereafter the contaminants can be analysed in more depth, either physicall y, chemically or microbiologically, if necessary. Organic contaminants are far more common than those from inorganic sources.

Examples of inorganic contaminants may include substance s such as plastics, metal and rubber, usually emanating from worn mechanical parts on the processing lines (conveyors, gears, gaskets and possibly filling machine components). Trimmings from plastic bottles and closures may also be a source. In some instances natural elements in underground water may cause undesirable effects. For example iron, if present, oxidises to form precipitates when exposed to air. There are permissible treatments that may be used to remove iron and other unstable compounds such as manganes e, sulphur or arsenic.

Non-microbiological, organic contaminants may include suspended solids or aggregates consisting of objects such as dust particles, paper fibres, hairs or insects. If the objects cannot be categorised, they are often referred to as amorphous (without form) particles, or amorphous matter. Sources of non-microbiological contaminants are numerous and could include the water itself, processing equipment, personnel, packaging materials (if stored incorrectly) or the external environment.

Contaminants may be microbiological in origin because although bottled water has relatively low nutrient levels,

some microorganisms are still able to grow in it, if given the correct conditions for growth. Growth is usually slow, unless there is gross contamination. Microbes may also be undetectable at bottling if initial numbers are very low. When present, and if able to grow, microorganisms aggregat e and proliferate to form noticeable clusters, or strands, in the water.

Microorganisms do not grow in carbonated beverages, including sparkling waters. Still water is more susceptible because the growth conditions (such as the availability of oxygen in air) are more favourable for microbial growth. Given that last year 65.7% of the bottled water demand in South Africa was for still bottled water, measures to eliminate contaminants are imperative and, if not successful, could destroy a brand.

Microbiological contaminants (excluding viruses which are very small) are clearly identifiable when viewed under the light microscope and include an array of organisms ranging from protozoa (microscopic animals) and algae (micro-scopic plants) to fungi (yeast and moulds) and bacteria (rod-shapes or spheres). Bacteria are the most common, followed more rarely by moulds.

As with any contaminant, the type of microorganism(s) in bottled water can give a clue to possible sources. Pseudomonas species, which are water-borne bacteria, are a common cause of “floaters” in bottled water. Therefore, the source of these organisms could be the water itself (e.g. from faulty filters), or from the processing lines, or bottling procedures. Most bacteria, including Pseudomonas, are well adapted to forming biofilms (layers of viable bacteria) that can form in difficult-to-clean areas; on rough surfaces; on certain susceptible materials (e.g. polythene) and/or due to a build-up in filters. Fragments of biofilm could become dislodged and enter the bottled water. Alternatively, water used to rinse and disinfect bottles and/or closures, if not carefully monitored and changed regularly, could be a

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The bottled water market in South Africa has grown phenomenally in recent years. Local consumptio n was reported to have increased by 34.7% from 2005 to 267.6 million litres in 2006 (including 1.3% of imported water). Last year new regulations were published to clarify the differen t categories of bottled water and to document the qualification for each type (refer “Regulations Relating to All Bottled Waters", Department of Health, No. R. 718 of 28 July 2006). The publication categorise d water as “Natural”, “Defined by Origin” or “Prepared”. Whatever the category, the potential proble m of contaminants is common to all and is the subject of this article.

by Gail Hagemann, Nampak R&D (May 2007).

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source of infection in the final product. This is particularly common in manual bottling operations.

If the contaminants are composed of coliform bacteria (e.g. Escherichia coli), this usually indicates a human or anima l source. Examples of human carriers include instance s where bottles and closures are handled manuall y. Hand hygiene plays an important part, and transfer of organism s may occur if packaging is handled unhygienicall y, as in touching the internal (product contact) surfaces. Insects, birds and other animals that have access to unprotecte d source water and/or uncovered primary packaging materials are also sources of coliforms.

Spore-forming bacteria and moulds usually come from the air in the external environment. When the product itself, or the packaging materials, are exposed to environmental air for long periods, the dust which can potentially contaminate the final product is accumulative. Higher dust levels not

only cause higher levels of contaminants in general, but also lead to increased spore levels (from bacteria and moulds) in particular.

All categories of contaminants can be prevented by good manufacturing practices (GMP), which includes good hygieni c practice (GHP). The “Guidelines & Standards for Bottling Lines” available from SANBWA are an excellent resource and give comprehensive notes on how to ensure good quality products. These are recommended for further information.

Should a problem of contaminants occur in any of your bottle d water products, identifying the type of contaminant is the most important step to solving the problem. Speedy and correct identification in the first place will save valuable time in the long run as there is usually a clue to the source in the identity of the contaminant.

References cited: Business Market Intelligence Report. Bottled Water in South Africa 2007. March 2007.

South African Natural Bottled Water Association (SANBWA) − Guidelines & Standards for Bottling Lines. Edition 2. March 2001.

Dorothy Senior & Nicholas Dege, Eds. Technology of Bottled Water. 2nd Edition. 2005. Blackwell Publishing.

Mould hyphae (filaments) originally at 200x magnification. Possible origi n: Exposure to external environment.

Photographs Depicting Various Types of Contaminants

Pieces of rubber-like materia l. Possible origin: Perished gaske t. Grid size is 3mm².

Plastic shavings (originally 10x magnification) Possible origin: Worn conveyor belts.

Wood chips. Possible origin: Wooden pallet s. Grid size is 3mm².

Black particles associated with dust. Possible origin: Exposure to environmenta l air. Grid size is 3mm².

Scanning electron micrograph of amorphou s matter & diatoms (average actual size 100µm). Possible origin: Filters consisting of diatomaceous earth.

A biofilm of bacteria (originally 200x magnification). Possible origin: Inadequately cleaned pipe-work, pumps, tanks etc.

An insect and mould hyphae (filaments) as indicated. Possible origin: Exposure to external environment. Grid size is 3mm².