Tuesday, 5 April 2011

Pseudalert from Idexx

Bottlers are familiar with Colilert in their day-to-day control of bottled water quality.  Colilert from Idexx determines the presence or absence of coliforms in water.  Coliforms are not allowed in bottled water and testing is done for every batch of bottled water produced.  Coliform bacteria can be found widely in the environment, in soil, water and on vegetation, but are also abundant in the faeces of warm-blooded animals.  While coliforms themselves are not normally causes of serious illness, they are easy to culture and their presence is used to indicate that other pathogenic organisms of faecal origin may be present.  The test itself is simple and uses a powder which is added to the water sample.  After incubation for 24 hours at 37 degrees C, a colour change from clear to yellow indicates the presence of coliforms.

A new kit for determining the presence or absence of Pseudomonas aeruginosa is now available called Pseudalert.  The procedure is similar to that indicated above except that the initial colour of the sample is yellow and, after incubation, the presence of Ps. aeruginosa is inicated by the presence of flourescence under UV light.  Ps aeruginosa is a pathogen which can cause infections in open wounds.  In a water environment, it is often associated with biofilm, a protective slime which serves to protect microorganisms.  Ps. aeruginosa is not allowed in bottled water, although it should have little effect on healthy individuals.  However, people with a poor immune system, mouth ulcers or throat lesions could be affected.  At high levels, the microorganism can cause off-tastes and odours.  Currently bottlers are testing for the presence of Ps. aeruginosa in their regular quality checks.

Monday, 4 April 2011

Hygienic Coatings

TV adverts for cleaning products show germs lurking around every corner. A recent survey from South Korea found that shopping trolley handles harboured more bacteria than any other commonly used item. The next most contaminated were the mice (computer variety!) in Internet caf├ęs, followed by hand straps on buses and bathroom doorknobs. Manufacturers are picking up on this growing public awareness by developing a range of antimicrobial products - everything from bathroom accessories to paint for hospital walls and food preparation areas, to coatings for surgical instruments.

Hygienic coatings are not new. Home decorators have been buying antifungal paints for kitchen and bathroom walls for years. US market leader Microban, for example, has become a household name by putting its antimicrobial agents in chopping boards and food containers. What is new, however, is the explosion of new applications for coatings. Recent applications have included water coolers and there are many other potential applications in the bottled water industry.

There are three major technologies in use today: silver, reactive silanes and organic biocides. The details are too numerous to be described in this short blog, but if you are really interested see “Antimicrobial Surfaces in the Food Industry” by T F Child, New Food, 2, 52-56 (2006).

For application in bottled water and cooler markets the essentials are:
No transfer into the water (no taint);
No discolouration or loss of transparency of plastic materials;
Must survive normal cleaning or multi-wash cycles and preferably be effective for the lifetime of the treated article.

Potential applications: water cooler reservoirs, pipe work, taps, casings, drip trays; replaceable plastic parts (for longer life);19L polycarbonate bottles; cap chute, capper head and filling area; floors, walls, doors and ceilings in the bottling plant. The ideal time to treat a building is when a new bottling plant facility is being set up, although post application is still possible. After cleaning, the product is sprayed on to surfaces and allowed to dry. The treated surface can remain active for many months.

For water cooler servicing, treatment of the tap area will give a long-lasting protection against microorganisms introduced from outside the cooler, either by users or the general environment.