Steam Cleaning: Is it a safe and effective alternative to chemical-based disinfectants?

Steam Cleaning: Is it a safe and effective alternative to chemical-based disinfectants?

One of the oldest methods of disinfection is the simple application of heat to water and either immersing an object into the boiling water or producing steam and directing the jet onto a surface. Soldiers of Alexander the Great followed the advice of Aristotle, to boil their drinking water to render it drinkable.

This method is so good that it is still used today in the sterilisation of medical and surgical instruments, abet in a more highly refined form. Today, the distinction between disinfection and sterilisation is clearly understood through advances in the understanding of bacterial spores and their ‘durability’ to harsh environmental conditions. Simply put, disinfection is a process where all or nearly all pathogenic microorganisms are eliminated from a surface, but not bacterial spores; Sterilisation is a process where all forms of microbial life is eliminated.
Beyond the technological advances made in sterilising medical equipment and invasive devices, most pathogenic bacteria are spread on common environmental surfaces like bed frames, door handles, switches or telephones. An infected person, not necessarily a patient, will touch or in some way interact with many different surfaces hundreds of times a day. Another person then joins the chain of infection by touching those same surfaces and transferring the bacteria to his/her mouth; a common habit we all share is that we repeatedly touch our faces many times during the day, without being aware of it.

Over the decades many different disinfection methods have sprung up to tackle this very problem, most of these technologies involve the use of chemicals, and some of these chemicals are particularly toxic. The drawbacks to the use of these chemicals are the cleaning methodology employed to make a surface ‘ready’ for disinfection, the required contact time and the on-going compliance to procedure in their usage. The efficacy of a number of these chemical disinfectants can be severely curtailed by the presence of organic soiling, in severe cases this soiling can harbour and protect bacteria from chemical disinfectants. All too often a quick spray and wipe is deemed to be sufficient for cleaning and disinfection, with little or no regard to the importance of each step in the process, including the necessary contact time.

Is the answer better training and accountability in cleaning and the use of chemical disinfectants? Clearly, cleaner training is absolutely crucial, regardless of whether new cleaning equipment is implemented. What is important is that cleaning, including the use of novel equipment, is taught and managed as an all-encompassing system. Not only does the cleaning staff need to know how to clean and disinfect, they need to understand the reasons why and the complications arising from non-compliance.

Could a single step steam cleaner replace all this multi-step process of cleaning and disinfection cleaner? There is limited peer-reviewed evidence that steam cleaners (sold as industrial steam cleaners) do in fact provide a more effective bacterial effect when compared to current chemical disinfectants. The steam cleaners used in these studies directs a jet of steam on to a cloth attached to a head, the cloth is then pressed against the surface and the steam provides the hot moist heat needed to effect disinfection; the cloth also functions to remove organic soiling as it passes over a surface. The advantage to this method over a jet of steam is ensuring the temperature is high enough and reducing aero bio-contamination.

However, one study (Meunier et al, 2009) found that the efficiency of steam cleaners, in comparison to chemical disinfectants, diminishes rapidly when the effective contact time is greater than the prescribed time. The minimum contact time seems to be equipment dependant, varying around the 2 minute mark per 4 square metre surface area. Another study (Tanner, 2008), utilising a novel steam cleaner, claim a 5 second contact time to inactivate an assortment of pathogenic microorganisms. This particular system introduces calcium carbonate (dissolved in tap water) crystals into the steam flow and it is claimed to have a disruptive effect on cell membranes.

A significant drawback to the steam disinfection method is the detrimental effect temperature and moisture has on some materials like plastics or adhesives. Another disadvantage with the use of pure steam to disinfect, as oppose to the introduction of auxiliary disinfectant chemicals, is that the effect is non-residual – the surface can become re-contaminated the moment the surface cools below the threshold temperature.

Both chemical and steam-based disinfectant systems suffer from the lack of a ‘fool-proof’ process: both systems require adequately trained personnel in order to efficiently and effectively disinfect a surface – there really is no magic bullet. When using the steam cleaning system, for example, the cloth must be pressed against the surface, or the jet of steam must be positioned close enough in order to deliver the require temperature, for the required time.

Refs:

Meunier O, Meistermann C, Schwebel A.. (2009). Effectiveness and limits of the cleaners steam in hospitals. Pathologie Biologie. 57 (3), 252-7 – http://www.ncbi.nlm.nih.gov/pubmed/18321661

Tanner BD. (2008). Reduction in infection risk through treatment of microbially contaminated surfaces with a novel, portable, saturated steam vapor disinfection system. AM J Infect Control. 37 (1), 20-7 – http://www.ncbi.nlm.nih.gov/pubmed/18834748

Rutala, WA Weber, DJ et al (2008). Guideline for Disinfection and Sterilization in Healthcare Facilities. CDC: Healthcare Infection Control Practices Advisory Committee. 8-12

Rafael Cobos
rafcobos@futurecleansystems.com