REPEAT RESULTS: The Science of Cleaning
Is cleaning an art? Or is it really a science? It’s a question that is bound to get lots of responses from cleaning industry veterans with vigorous arguments being raised on both sides in favor of their respective points of view. As a cleaning industry consultant with many years in the business, I’ve had an opportunity to consider the question and it is clear to me, and to a growing number of professionals in the industry, that cleaning is a science.
When we look at something that is an art we see something unique, something that is not exactly the same as another product of the artist – maybe similar to it, but not exactly the same. That’s the great thing about an art, it’s always new, always different, sometimes spectacular, but never, ever the same.
Science demands exactitude and proof. For a fact to be scientifically proven it must be reproducible. That means that by following the method, the result will always be identical. The products of scientific processes are reliably the same; while this may sound boring, it is that very quality that makes for the most effective cleaning process.
Consider mopping a floor with a conventional mop, bucket and wringer. The floor is dirty, soiled by debris from foot traffic, spills, and dust. The person mopping the floor will continue to mop and wring and rinse, and mop and wring and rinse, until the water is judged to be too dirty to continue. In fact, the second time the mop was rinsed the water became soiled and therefore less likely to be any great use in cleaning the floor. The operator has to judge how often to change the cleaning solution and this frequency will vary partly depending on how soiled the floor is. In addition, the operator needs to be extremely skillful when mopping edges and corners to avoid leaving soiled solution in those areas to dry into crusted ridges of dirt that need extra labor to remove. Clearly, this method relies on a lot of judgment on the part of the cleaner; maybe that’s why some will claim that cleaning is an art.
If mop and bucket cleaning is an art this explains the wide variety of results we see when this method is used. Worse still, what we can’t see is the level of biological contamination left behind by this method. To protect the health of building users, the cleaning service provider, both in-house and contractor needs to be able to demonstrate that proper, effective cleaning is taking place, this time and every time. The only way to be sure that this is happening is by cleaning in a way that guarantees a clean result every time, and that would be able to be reproduced by different operators with complete reliability. This kind of cleaning is truly a science.
Spray and vacuum cleaning is being recognized as a more scientific method of cleaning by industry leaders. The method involves cleaning solution applied under pressure to soiled surfaces which is then vacuumed up into a soiled solution tank. This method, also known as High Flow Fluid Extraction HFFE provides the necessary actions needed to clean surfaces. The pressure of the solution spray dislodges dirt from both flat surfaces and from crevices and corners; the liquid holds soil in suspension to be vacuumed up, leaving a minimum of solution on the surface, which then dries quickly. Faster drying reduces the opportunity for fungal or bacterial growth particularly along edges and corners where mopping almost never is effective. The cleaning of grout lines in washrooms and showers is particularly effective using this method as soil laden liquid is suctioned out of the grout lines rather than being swept into the grout lines as happens when wet mops are used. Since fresh cleaning solution is constantly being applied there is no risk of soiled solution being reapplied to the surfaces being cleaned, and no requirement for “judgment” on the part of the operator.
The results of any cleaning process must be measured if we want to be sure that it is effective at removing soils and leaving behind a clean safe surface. Fortunately, in recent years there has been considerable scientific study of cleaning methods as well as improvements in testing methods to verify cleanliness levels. A study by Gerba, Wallis, and Melnick (1) demonstrated a phenomenon referred to as the “toilet sneeze”. They explained how fecal matter and enteric bacteria get from the toilet to other restroom surfaces. They showed that the flushing of a toilet spews tiny droplets containing fecal matter, urine and bacteria into the air and then eventually onto floor surfaces throughout the restroom.
A simple test identifies the presence of urine on washroom floor surfaces and in the grout lines of tiled washroom floors.
The presence of urine is a reliable indicator that other contaminants such as E. coli are likely to be found on the surface, therefore a cleaning method that produces virtually urine-free surfaces is likely free of other contaminants. Tests conducted for Kaivac Inc. have shown that the HFFE process produced consistently cleaner surfaces than using either conventional or flat mop techniques.
In a recent article discussing the merits of spray and vacuum cleaning, Dr. Paul S. Darby said: “The traditional cleaning method essentially turns a restroom floor into a very large culture plate, supplying ample water and nutrition to disease-causing organisms that can rapidly proliferate.” Dr. Darby operates an active consulting practice in medicinal chemistry and biotechnology. He is board-certified in Occupational and Environmental Medicine and is in full-time practice, specializing in acute industrial trauma, chemically-related illness, and maritime medicine.
At a time when there are great concerns about resistant infectious organisms, the cleaning industry and cleaning service providers have a huge responsibility to protect health by cleaning effectively in a way that guarantees consistent results; a scientific way, because cleaning done properly is a science.
1 Gerba, C. P., Wallis, C., Melnik, J. L. 1975. “Microbiological Hazards of Household Toilets: Droplet Production and the Fate of Residual Organisms”. Applied Microbiology, August 1975, p 229-237.