* Cleanzine-logo-8a.jpgCleanzine: your weekly cleaning and hygiene industry newsletter 9th July 2020 Issue no. 926

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We have Mail: Response to Survey reveals professionals "unclear about proper cleaning / disinfecting procedures"

Dear Sirs,

P&G Professional's recent survey 'Cleaning & Disinfecting Clarity' highlighted a common misunderstanding within the industry as to the most effective method to clean and disinfect a surface. It is a lack of proper and consistent training that, in my opinion, is at fault.

Unfortunately the lack of proper instruction goes beyond the process of disinfection, it is evident in nearly all aspects of cleaning where there are conflicting instructions from each product and equipment manufacturer as to what the most efficient cleaning process should be. The manufacturer might know best for their own product lines, but obviously that doesn't reflect the market as a whole.

With regard to the process of disinfection as a part of a cleaning routine, it is imperative that the high standards of cleanliness be maintained on all surfaces that warrant the use of disinfectant agents: food preparatory surfaces, surfaces in contact with food products, surfaces capable of harbouring an infectious agent (formite), etc. So, it is important to inform and instruct the cleaning team responsible to approach the process as a cleaning system, rather than relying completely on one or more products.

The disinfectant products themselves can be shown to be effective against a range of infectious organisms, this is backed up by independent microbiological testing, and is often quoted as a sort of 'kill potential' after a certain contact time.

However, laboratory testing is just a model and cannot realistically reflect the real world's many variables such as different types and degrees of soiling, surface materials, environmental conditions, dwell time and the porosity of all surfaces including the cleaning equipment used.
That is not to say that laboratory test results should be ignored - far from it - they provide the basis for an informed choice as part of product procurement standard(s).

The use of disinfectants abides with the most important principle - a dirty surface cannot be sanitary. Soiling on any surface, whether that is light soiling or heavy soiling, provides the base for the growth of microorganisms.

Microorganisms become attached to the soiling (broadly through the formation of bio-films) and can become entrapped and act as a barrier, preventing contact with the disinfectant. It therefore follows that the cleaning process must remove all the visible soiling from the surface, before the disinfection process can begin.

The cleaning stage, although doesn't act as a biocide, breaks and suspends the soiling within the cleaning solution, also suspending the microorganisms. The cleaning solution then needs to be completely rinsed away, which prevents the redeposition of microorganisms on to the surfaces.

An added complication to this mix is that bio-film can act like a defensive 'shield' against the local environment and as such can form a physical and chemical barrier to disinfection agents - Legionella is known to be resistant to disinfectants within its biofilm structure. The choice of detergent, therefore, must ensure biofilm breakdown.

Once the surface is visibly clean and rinsed off, the surface can be disinfected, observing the recommended dwell time. Even the choice of disinfectants can display varying degrees of efficacy and nearly all are prone to chemical interactions to some degree, which often reduces the effectiveness of the disinfectant.

For example, the effectiveness of Quaternary Ammonium Compounds, one of the most widespread groups of compounds that display good antibacterial properties, can be reduced in the presence of organic matter, certain ingredients in detergents (anionic surfactants) and inorganic salts (hard water).

As it can be seen - and I have only really just scratched the surface - the process of disinfection is an ordered procedure that tries to ensure consistent and repeatable results. Using an 'all-in-one' disinfectant cleaner as a shortcut for proper cleaning standards, negates the necessity of why such processes are needed in the first place.

Whilst these types of cleaners can be used when the soiling is very light or where the risk of contamination is relatively low, they cannot be used as a replacement for a separate clean and disinfect in all other areas and other degrees of soiling.


Rafael Cobos AMIMarEST
T: (01946) 810867
E: [email protected]

As a Consultant with Futureclean Assured Systems, Rafael Cobos advises on all aspects of infection control, disinfection and hygiene-related issues in all high-risk industries. Being completely independent of manufacturers, he is able to advise clients on the procurement and use of cleaning products and equipment.

Ref: Rutala A.William et al, Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008, CDC

29th March 2012

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