How clean is clean?

Cleaning is the process of removing unwanted matter from an environment, such as a building. But how clean is clean? And how do we measure to determine whether the cleaning process has left the building free of unwanted matter? – Facilities Manager magazine does not only raise questions but provides answers as well.

Sometimes measurement of cleanliness is simple and straightforward. The outcome of effective window cleaning for example is seen visually with crystal clear windows. Alternatively, the outcome of an ineffective window cleaning process is equally visible. 

And what happens when the cleaning outcome is poor, but the results are not easily perceived? Without good measurement science, determining whether a cleaning process has been effective is quite difficult. Does this mean that, if poor cleaning results are not detected, the ineffectiveness cost is saved? Or does it mean, rather, that the cost associated with ineffective cleaning has been wasted? – experts of Facilities Management magazine, Greg Whiteley, PhD, M Safety Sc, Eugene Cole, DrPH, and John Downey raise the questions. 

Consumers are concerned about the level of cleanliness where they work, study, and live 

That is why it is important to measure cleaning effectiveness in addition to the labour and material cost of the cleaning process. The best way to measure the effectiveness of a cleaning process is to measure before and after the cleaning. Unless cleanliness can be shown to be measurably better after the cleaning process is finished, the cleaning is ineffective and the investment is wasted.

At the same time, certain infectious agents are non-visible to human vision but still pose serious health risks to humans. For example, a variety of microorganisms that can cause infectious illness in humans may enter a building via already-infected people who may not know they are carrying the microbes. Microbes from an infected person can also spread via direct contact with an inanimate surface when a non-infected individual touches such a surface previously touched by an infected person. The cycle of transmission is perpetuated without the infected and the uninfected persons ever coming into direct contact.

The critical role of the cleaning process as it relates to health is to remove these microbes, together with other dust particles and soils, from the building’s highly touched surfaces so that the cycle of disease transmission is interrupted.

The emphasis on high-touch surfaces (HTS) is perhaps the most important point to remember. A significant focus of building cleaning as it relates to health impact should be on effective cleaning (removal) and, as required, disinfection (inactivation of residual microbes) of HTS.

How to detect harmful and non-visible microbes?

What is needed is a good indicator test that will provide a quick answer so that timely action can be taken to correct any cleaning deficiency or cleanliness problem. Fortunately, there are now a variety of quick and convenient measurements that have been scientifically proven to provide a useful indicative measure of the cleanliness of a building’s HTS. The major approaches used to measure surface cleanliness are microbiological testing and dust sampling and residue testing.

Microbiological testing

Testing a surface for microbes is the gold standard of surface cleanliness measurements. Unfortunately, with so many different microbes to test for, it costs too much and takes too long for ordinary use. That said, when there is a specific disease of concern, there is no better method than microbial sampling. Modern technology is making the process of recovering microbes and identifying those of concern much easier and faster – turning weeks into days.

This is highly relevant for disease outbreaks associated with food poisoning, gastrointestinal illnesses, or healthcare-associated infections. Also in buildings where dampness and mold are a problem, surface sampling is a reasonably quick and easy approach to microbial testing. This would apply to buildings affected by flooding or other forms of water damage.

Dust and residue testing

Dust in buildings can act as a food source for microbes, insects, and other vermin. And all of it has the potential to impact the health of the human occupants.

In some circumstances, chemistry testing through dust sampling or residue testing is also a gold standard for environmental monitoring of cleanliness. Samples can be collected from the air via a suction sampling device and quantified and assessed for size. Particle counters are also a real-time tool for assessing the quantitative presence of airborne dust in a location.

We do know that poorly maintained equipment, such as vacuum cleaners, can easily spread dust rather than capture and remove it from a building. The use of well-maintained, high-performance vacuums is critical to ensure effective cleaning and minimize dust resuspension.



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