The Dangers of Drinking Pure Water?

100% natural pure water is difficult to find in nature.  As soon as rain hits the ground, it becomes mineralised.  Humans have been drinking mineralised water since they existed on earth.  If water is demineralised by reverse osmosis or distillation and we drink it, will this be something the body is not used to?  Will it do us any long-term harm?

The debate has been running for a long time.  If you look at the "The Natural Mineral Water, Spring Water and Bottled Drinking Water Regulations (England) 2006", the minimum hardness concentration in water sold to the general public must contain a minimum of 60 mg/l calcium.  However, hardness consists of a complex mix of polyvalent minerals, the main component of which is calcium.  Is adding a calcium salt to RO or distilled water up to 60 mg/l the same thing?  Probably not.

The reason often given for the need to maintain a minimum of 60 mg/l calcium is a body of epidemiological evidence that hardness in water has a benefit to cardiac health.  Does this infer that the absence of hardness salts could damage cardiac health?  Since the 2006 publication, the debate has continued over the years, with involvement of the Food Standards Agency, the WHO, The Scientific Advisory Committee on Nutrition and the bottled water industry, to mention a few.

A number of health aspects of water with or without hardness salts have been considered, including osteoporosis, hypertension, stroke, insulin resistance and epidemiological studies of water hardness (or lack of it) and cardiovascular disease.  These assessments are on-going and until a definitive conclusion is reached, water for human consumption, treated by osmosis or distillation, remains regulated at a minimum of 60 mg/l calcium re-mineralisation.

USE OF PHOSPHORIC ACID AS A DESCALER/DISINFECTANT IN COOLER SANITISATION

Phosphoric acid is sold as a descaler for application in cooler sanitisation procedures.  The manufacturers make no claim for disinfection and the technical data sheets refer only to use as descaler.  Disinfectants are highly effective at reducing microbial counts, even at very low concentrations, for example, hydrogen peroxide and peracetic acid.  Very strong acids will kill microorganisms, although their use in this manner is wasteful and can be dangerous.  However, a common problem with coolers is a tendency to build up both scale and biofilm and acids can be useful in helping to remove both.

In its simplest description, biofilm is a colony of microorganisms attached to a surface and protected by a self-generated protective film of polysaccharide.  This can occur in coolers and Pseudomonas aeruginosa is particularly adept at colonising surfaces and generating protective films.  Surfaces covered with scale are particularly susceptible to attachment by microorganisms.  They enjoy the ease with which a foothold can be made; smooth surfaces are more difficult to colonise.

Acids have the ability to dislodge and dissolve scale, provided the strength is high enough.  In dislodging the scale, they will also dislodge the attached biofilm and therefore help in its removal.  In this respect, acids will aid in removing microorganisms.  However, biofilm attached to plastic or stainless steel surfaces can resist  removal by acids, in fact older biofilms are very resistant to conventional chemicals such a phosphoric acid and chlorinated materials.  In this case the biofilm will remain intact and continue to protect the bacteria, including Ps. aeruginosa, gradually releasing the bacteria into their immediate environment over a period of time.  Oxidising acids, such as peracetic or nitric acids will attack biofilm successfully in this case.  Phosphoric acid is not an oxidising acid.

Phosphoric acid is a useful descaler in the cooler sanitisation procedure.  It will help in reducing microbiological count by removing scale which becomes coated with biofilm.  However it cannot be considered as an effective disinfectant and is not “heavyweight” enough to fulfil this role.  Descaling with phosphoric acid should always be followed by treatment with a disinfectant, such as hydrogen peroxide.

Simple Rules for Bottling Plants

1.       Segregation – The filling area should under a positive air pressure, to avoid inflow of contaminated air.  HEPA filters should be used to filter the air and these should be checked regularly to avoid blockage.  Either the filler should be treated in this way or the whole bottling plant should be under positive pressure if the filler is not enclosed.  Entry into the area must be limited to essential personnel wearing appropriate protective clothing.  Aseptic filling requires very high standards of hygiene and preferably should be run automatically and remotely from human participation.  When this is not possible, the operator should be specially trained to work in an aseptic environment.

2.       Process lines – The distance between the filler and capper should be as short as possible and likewise the distance between the blow moulding unit and the filler, although in the latter case this is not always possible.  Companies filling glass bottles must have a “glass breakage policy” to detail actions taken when glass breakage occurs.  If conveyor lubricants are used, these must be of the H1 grade (approved for indirect food contact).

Hygienic Design and Location of Bottling plants

1.       Site – avoid locations that could create problems in the future, e.g., nearby chemical works, rivers that may flood, farming environments.  The latter are a significant risk if animals are close by.  Transport of contaminants on footwear into the plant can be a big issue and there is a higher risk of pest infestation, both from flying insects and rodents.  Many bottling plants are located on farmland where the spring source originates.

2.       Building – the building must be fit for purpose and approved for food production.  It is unwise to use converted barns and the building should be purpose built.  A high-risk area should be defined within the building where product in open bottles is present.  The bottling plant should be sealed off from the external environment and no external doors should open directly to the outside.  Windows should be non-opening preferably or, at least , fitted with insect grills.  Glass should be strengthened and shatter-proof, this applies to windows, doors and lighting.  Drains should be fitted with traps and kept clear of blockage.  Toilets and canteen areas should not open directly into the plant area.  A hygiene and cleaning schedule needs to be created for the whole building based on the risk analysis highlighted by the HACCP programme.  External areas should be policed for excessive rubbish accumulation and encroachment of vegetation.

Sanitising Sealed Mains-Fed Water Coolers

Sanitising sealed mains-fed water coolers can be difficult but not impossible.  The main issue is how to get the descaling and disinfectant liquids into the unit. Typical units are the direct chill or spiral chill type.  Frequency for sanitising and filter changes is every 6 months.

The filter housing can be disconnected from the microbore tubing and a small device known as a venturi doser put in its place.  The doser is filled with the recommended amount of descaler and the hot tap actuated.  This will draw descaling acid solution into the tank.  After descaling, flush with at least 4 litres of water and test with pH paper until neutral.

The spiral chill pathways can be descaled and then disinfected using the same technique with respectively phosphoric acid (for example) and hydrogen peroxide.  The chemical is drawn from the doser by actuating the chill tap.  When the chemical begins to run from the tap (you can check this with pH paper or peroxide test strips), turn the tap off and wait for ten minutes.  Then flush with water until the test strips are clear.

This is not a detailed procedure and coolers vary considerably in design, however it will serve as a guideline.  Always check with your cooler supplier if in doubt.

Descaling and Disinfecting Water Coolers

The hot tank of coolers can be descaled using an acid such as phosphoric or citric. Sometimes other internal  parts of coolers need to be descaled and disinfected.  Scale build up in reservoirs, for example, is usually not severe but can lead to microbiological problems if left.  Attachment of micro-organisms and ultimately formation of a biofilm can rapidly cause deep-seated contamination which is not always easy to remove.

It is common practice to use a descaler, accompanied by mechanical action such as brushing, followed by a disinfectant such as hydrogen peroxide.  This will remove the scale and destroy the biofilm.  In some practices it is considered that one application of acid is sufficient to descale and destroy biofilm.  This is not always the case and is very dependent on the strength of acid used.  Very strong acids will do the job but these are usually applied diluted.

Diluted acids will remove scale more slowly and much of the acid is used up in this process.  In this case biofilm will not be removed.  If you want to use acid alone, then either use very strong acid (not recommended from a safety point of view) or use the acid in two steps, one to descale and the other to kill bacteria.

An alternative is to use an acid containing a disinfectant component which can then act as a sanitiser while removing scale.  These are available on the market.  However, the preferred method is to descale and then disinfect, in two separate steps.