Long-Lasting Hygiene Protection for Bottling Plants and Water Coolers

Some time ago, I wrote about antimicrobial coatings in the Food Industry ("Antimicrobial Surfaces in the Food Industry", New Food, 2, 52-56, 2006).  Applications in the bottling plant and for treatment of water coolers are now a cost-effective reality.  Applied by spray, these treatments provide constant protection against bacterial growth on many types of surfaces within the bottling plant, particularly those areas susceptible to mould growth.

In addition, treatment of door handles or plastic curtains will prevent growth and transfer of bacteria from these surfaces.  The spray should be applied onto a clean, dry surface and allowed to dry.  The product will continue to suppress bacterial growth and mould growth for an extended period.  Areas within the bottling plant where the product may be used are on ceilings and in corners where mould growth usually occurs, on the cap chute and in the machine above the filler head.

Consider treatment of taps or buttons on watercoolers and also drip trays and cup holders.  An obvious application is in toilets for treatment of door handles and taps.  A version of the product is available with detergent included, for easy sanitisation of smaller surfaces, such as cooler casings and fountains.

This technology was originally devised for a hospital environment, but application into the food and beverage industries soon followed.  Application in bottling plants and for water coolers is a logical next step.  One word of caution, application of this product does not mean that you can forget all other cleaning and disinfection in the bottling plant or the water cooler clean room.  It should always be considered as a second line of defence to complement other hygiene measures in your due diligence regime.  

Measuring Concentration of Bottle Wash Detergent

Still doing titrations?  Many bottlers have switched to using conductivity meters to measure the concentration of bottle wash product in the tank.  With advances in technology, conductivity meters have become smaller and easier to use.  The price also has  fallen considerably.

Using conductivity meters could not be simpler, just take a sample from the wash tank and dip in the meter.  When the reading stabilises, look up the reading on a calibration chart and this will give you the concentration.

The pocket conductivity meters are temperature compensating, available in basic form for measuring just conductivity, or more sophisticated systems will also measure TDS, temperature and are self-calibrating.  They are waterproof and also float should you accidently drop them into the wash tank.

If you operate a high throughput machine, then conductivity probes may be used in the machine linked to automatic dosing pumps which maintain a fixed concentration of the product throughout the day.  The concentration of the product in the wash tank will reduce over the day caused by drag-out from the bottle movement and it is necessary to compensate for this loss

Detecting Biofilm and Mould in the Bottling Plant and Water Coolers

How do you detect contamination in your bottling plant or water cooler?  There is a wide variety of diagnostic techniques available these days to help.  Identifying the presence of biofilm or mould can be done in the old fashioned way by feel or using the experienced eye, but it is best to rely on additional help from diagnostic tools.

If you want an immediate answer to the possible presence of biofilm or mould, a simple swabbing test will give you an answer in 10 minutes, based on a colour reaction.  If you want a more quantitative measure of contamination then the use of an ATP meter is required.  These are available in pocket meter format.

If you would like to identify specific bacteria then several techniques are available, some based on pre-made plates with identification charts of the bacterial growth.  You will need a small incubator to use these plating techniques, however the savings on external lab costs will soon pay for the outlay.

A wide range of diagnostic kits is available, including Colilert, Pseudalert, dip slides, SIM plates and Petri plates as well as associated equipment.

Descaling and Disinfecting Water Coolers

Water coolers are prone to scale up if the spring or mineral water is heavily mineralised. The procedure for descaling is not standardised and different techniques are used by different clients.  For rapid descaling, the acid is used in concentrated form, although this may cause safety issues in handling.  Simple dispensing devices are available for this task which avoid manual operations.

The most important operation is disinfecting the water cooler.  Biofilm can easily form during the 3 months between services and this must be removed to prevent further build up.  Biofilm is notoriously resistant to several disinfectants including hypochlorites.  The ideal disinfectant for this purpose is hydogen peroxide.  It will penetrate and remove biofilm without leaving any taint.  Decomposition products are simply water and oxygen. Stabilised products are required to maintain an adequate shelf life and the stabilisers must be food grade materials.

Treatment of taps, air filter, waterguard and spigot are easily accomplished using a peroxide spray while the main reservoir and internal pipework are best treated with a solution of peroxide.

New sprays are available for cleaning and disinfecting the body of the cooler, drip tray and cup holder which have a long-lasting anti-microbial effect

Best Products for Washing Polycarbonate Bottles

I am often asked about bottle wash products and the difference between those on the market.  There is a difference between the products offered and it is valuable to know what these differences are.

Many bottle wash products sold in the UK are alkaline.  Alkaline products are particularly good at removing particulate soil.  Ideally the product should also contain a water softening component which enables a good clean to be obtained even in water with high mineral content.  Even better, if the product contains a biodegradable detergent, this will enhance cleaning and help draining.  It is essential, of course, that the detergent is low foaming at normal wash temperatures, i.e., above 60 deg C.  If you do not see any foam in your bottle washer, this important component is not in your bottle wash product.

Remember, most of the soiling is on the outside of the bottle, particularly the base, where soil is picked up from wherever the bottle has been standing.  Too much caustic or, indeed, too much acid is undesirable and it is a mistake to take products which are normally sold into the dairy industry; these are fine for cleaning steel piping, but not polycarbonate bottles.

However, occasionally there are limitations to the use of alkaline products.  If your bottle washer does not possess a heater and you have to carry out a cold wash, you need something in addition to ensure good bacteria kill.  In this case, use an alkaline cleaner which contains a disinfectant component, such as hypochlorite, but be sure to rinse thoroughly afterwards, otherwise you may get taint problems.

Contamination on Footwear in the Bottling Plant

Apart from airborne infiltration, the second most common entry of microorganisms into your bottling plant, or cooler servicing room, is on the soles of boots or shoes.  This is particularly the case when the bottling plant is located on farm land.

Our colleagues in the food industry solve this problem by allowing only rubber boots as footwear and creating a foot-dip area at the entrance to the plant, or to use plastic overshoes which are discarded after use.

We all know that in the bottling plant these facilities often are not available and therefore it is essential to keep the floor as clean as possible during the shift.  Entry into the bottling plant or cooler servicing room should be restricted to essential personnel and preferably the plant should be sealed off to limit access.  Of course, if a bottle jam occurs this has to be rectified quickly, but an awareness of foot contamination needs to be reinforced with anyone allowed access to the plant.

Preferably use a sanitiser or terminal disinfectant that has residual properties so that the bacteria kill will continue throughout the shift.  The best ones are based on mixed disinfecting components using, for example, quaternaries and biguanides.  These will provide a powerful and long-lasting deterrent to foot-borne microorganisms.

Bottling Plant Disinfection Before Start-Up

Overnight, during shutdown, your bottling plant accumulates bacteria and algal spores. They float in through the doors as people leave or become dislodged from roof areas by draughts.  By the morning the washer/filler is contaminated.

Rather than start up with a contaminated washer, it is becoming good practice to disinfect the machine before operations begin.  Ideal for this purpose is treatment with a fine spray of hydrogen peroxide.  There is no need to rinse afterwards and there will be no problems with taint.  It is important to wear a face mask and face shield during this operation, to protect eyes and avoid inhalation of the fine spray.

Hydrogen peroxide at ready-to-use concentration is available or a more concentrated product is available in 25L containers for use with a venturi spray system.

An alternative approach is to use sachets of chlorine dioxide-generating materials.  The sachets are placed in water and the chlorine dioxide gas evolved disinfects the washer/filler and surrounding area.

Yet another option is to use peracetic acid.  This is normally delivered at 5% concentration and requires dilution down to a use concentration of 0.5% of the 5% product (about 250ppm).  In each case, the disinfectant should be allowed to work for a period of 10-15 minutes before start up.

It is good practice to rinse the pipe line from the holding tank to the filler with disinfectant solution before start up (make sure to rinse).

For general disinfection of floors and walls use a mixed quaternary product because this has a residual effect which continues to work overnight.

Hand Sanitising

Hand sanitising is important, not only in the watercooler servicing room, but throughout the bottling plant.  Handling caps in the hopper, handling filled bottles, adjusting filler heads or clearing bottle jams all have the potential for transfer of bacteria.

Hands should be washed before entering the bottling plant or watercooler servicing area, after using the toilet, after coughing or sneezing and after touching any part of of the face or hair.  The location of hand-wash stations should be pointed out to new employees and a demonstration given of the correct method of hand washing and drying.

It should be emphasized that when gloves are worn, the hands within the gloves, as well as the gloves themselves, must be maintained to the same standard of hygiene.  If you go out of the bottling plant area and then back in again, you should wash your hands.  If you are wearing gloves, operators should change into a new pair of gloves on entering the bottling plant again.  This can be inconvenient if you are out for just a couple of minutes, and some operators forget to do this.

It is important to have a good hand sanitiser or hand disinfectant available, preferably the alcohol-based type which dries quickly on the hands without need for a paper towel.  If you come into the plant area with gloves, after being out for a few minutes, you can also treat the gloved hand with sanitiser without need to change into a new pair.

Hygiene Issues with Tap Water and Bottled Water

There have been many comparisons written and preferences aired about tap water and bottled water in various publications and forums.  Tap water and bottled water are very different in many aspects, but in this article I am concentrating on hygiene issues.

Bottled water is regarded as a food and therefore the hygiene requirements are in line with food production.  Certain pathogenic microorganisms are tolerated in tap water, such as Pseudomonas aruginosa, which are not allowed in bottled water.  The parasitic cryptosporidium cannot pass through the filters used in bottling water, but sometimes this microorganism finds its way into tap water because it is resistant to chlorination and the filtration process used is not able to remove it.  Both these microorganisms can be harmful if ingested by individuals with a low immunity level.

Because cryptosporidium is is a fairly large microorganism, filters prevent access to mains-fed water coolers.  However, it is important to have good filtration devices and to have your cooler serviced regularly.

Another issue with mains delivered tap water is the possibility of biofilm build up in the pipe work.  If left undisturbed, the biofilm does little harm, but if there is a pressure surge in the water supply the biofilm may rupture and release a large colony of bacteria, often Pseudomonas aeruginosa.

Most contamination of bottled water arises from airborne bacteria or from using older 19 litre bottles which have stress cracking in the form of microcracks.  It is difficult to clean and disinfect old and damaged bottles and they should be removed during initial inspection.

Airborne bacteria may enter the water at that critical point during and immediately after filling, before the cap goes on.  The time between these operations should be as short as possible and the bottlewasher/filler should be under a positive air pressure, so that airflow is out of the filler rather than into the filler.  Remember that a stream of water draws air towards itself by displacement.

Another difference in requirements between bottled water and tap water is that migration of substances from packaging (bottles) follows food regulations, whereas migration from pipe work in municipal supplies follows other, less strict, regulations.

After a long dry spell, the first rains wash all the accumulated bacteria and algae into the rivers and waste water systems, resulting in a huge increase in the bio loading arriving at the water treatment plant.  This is detected by the water companies and additional disinfectant measures are taken, but more people seem to get sick about this time.

Although I would prefer to drink bottled water from a hygiene viewpoint, it is extremely important to remain diligent in your bottling plant hygiene operations, particularly if you are in a farming environment, you will be surprised what can float through an open door into your bottling plant.

Spray Cleaning in the Bottling Plant

If you have a fairly large floor surface area in your bottling plant or loading area, spray cleaning is often employed.  This speeds up the process and if you have suitable equipment, the spray device will enable you to spray detergent, followed by a water rinse and provide a final spray with a terminal disinfectant, all from a single piece of equipment.

This multi-purpose spray equipment is not as expensive as you may imagine and certainly speeds the wash-down and terminal disinfection tasks.

One of the dangers of spray cleaning is the possible formation of aerosols.  If the pressure is too high, instead of just wetting the surface, an aerosol cloud containing water droplets, detergent and bacteria will be generated within the bottling plant.

The airborne bacteria will cover the total installation and your good work can be undone easily.  So, keep pressures down, or alternatively use a foaming device, which is by nature at a lower pressure.

A good terminal disinfectant for large surface areas is a mixed quaternary.  This has the advantage of possessing a residual effect without acclimatisation and will continue to kill bacteria overnight.

Contamination of Bottled Water

The nightmare for any bottler is when complaints start coming in about a bad taste in the water.  The immediate question of "what can be the cause?" unfortunately has many possible answers.

Initially consider whether anything has changed: a new bottle wash chemical: a change of machine configuration; a new supplier of bottles or caps; a new customer; a new bottle wash operative.  The list is endless.  Of most concern is whether the taint is caused by bacterial contamination, however, if all your checks have been carried out correctly, this is unlikely.

There are always unknowns which are linked to the customer and the fate of the bottled water at the customers' premises, such as storage conditions.  If you are not responsible for servicing the cooler, this is another area of concern.

Polycarbonate is a porous material and small molecules can enter into the water through the bottle walls.  When you consider that coffee has over 1000 flavour components, storage of bottles near to coffee machines is not a good idea.

Polycarbonate is also susceptible to stress cracking and this appears initially in the form of microcracks, often inside the bottle.  These are wonderful havens for bacteria, algal spores and chemicals, none of which can be rinsed out easily.  The problem is that these residues are not normally detectable by your usual quality checks and the offending material will seep out only after a period of time, usually when the bottle is with the customer.

How can you guard against this?  Well, use a bottle wash chemical that does not cause stress cracking and one that contains a detergent ingredient that can penetrate into microcracks and flush out anything lurking in there.  Try not to use chlorinated bottle wash products if you can help it, unless you have a very efficient rinse process.  Discard older bottles that are beginning to form microcracks.

Keep a stock of selected diagnostic test materials, so that if taint arises, you can undertake rapid assay of the possible contamination.  Watch out for bottles that are beginning to look stressed when they come in for washing.  Remember, taint issues usually occur only after the water has left your plant.

Microbiology Testing in the Bottling Plant

These days there are many diagnostic techniques available to bottlers and watercooler companies who want to take the do-it-yourself approach.  These techniques can shorten the time to obtain a result such as TVC and save you money.

Which technique you choose depends on the degree of accuracy required.  Dip slides have been around for a long time.  These are a low-cost and convenient option for assessing bacterial contamination.  A slide is dipped into the water sample, returned to the transparent container and incubated for 24-48 hours at 37 degrees C.  After this time, the colony count is compared with a series of photos which indicate the degree of contamination.

New developments in dip slides enable you to determine different bacteria types on each side of the dip slide, for example, TVC on one side and Ps. aeruginosa on the other.  The dip slides also are hinged at the top, which allows surface sampling.

An alternative system called Petrifilm (TM) enables you to obtain an accurate count of CFU per cm2 from a measured volume of water.  A 1ml sample of water is taken with a disposable pipette and added to the centre of the film.  The film is then covered and stored in an incubator at 37 degrees C for 48 hours.  Counting CFUs is made easy by a red indicator dye which colours the CFUs and a built-in grid which enables the CFUs per cm2 to be determined easily.

If you want an immediate indication of contamination, then you require an ATP meter.  Dip a swab in the water or swab a surface to be assessed and place the swab in the meter. An immediate numerical reading results.  Now, this is not the actual TVC, but an indication that contamination is present.  The higher the reading, the greater the contamination.