By Ayisha I. A. Malik, Cole-Parmer, EMEA
A deep dive into cleaning, disinfection, sanitisation and sterilisation
Your workplace environment has a direct impact on your employee productivity and wellbeing. In every industry, maintaining a clean workplace has a huge impact on overall worker satisfaction. With the current focus on pathogenic virulence and disease persistence, hygiene and cleanliness has become a common topic of concern for everyone.
According to the Centers for Disease Control and Prevention (CDC), 80% of infections spread through direct and indirect contact at the workplace. Additionally, staff illness has a sizable impact on productivity for any business, with more absences and generally lower morale. With the current emphasis on safe return to work, hygiene and cleanliness have a newfound importance. With so much at stake, it is important to understand the cleanliness requirements for different workplaces. This is determined by the nature of the business, the materials being handled, and personnel health and safety requirement. Workplace decontamination can be classified into four main categories – cleaning, disinfection, sanitisation, and sterilisation; however, these differ in both purpose and outcome.
Cleaning is the most basic form of decontamination required at any place of work. It refers to the manual or mechanical removal of visible debris, dirt and dust from objects and surfaces using water and detergents or enzymatic products.
According to the United States Environmental Protection Agency (EPA), cleaning with soap and water decreases pathogen load on surfaces and objects, reducing the risk of exposure to dangerous germs. Additionally, thorough cleaning is a prerequisite for high-level disinfection and sterilisation. If organic and inorganic materials remain on the surfaces, it can interfere with the effectiveness of further decontamination processes.
While there are many brands of detergents on the market, soap in its basic capacity, works by breaking up oil-based compounds into small enough particles that can then be washed away with water. The CDC recommends washing hands with soap and warm water for 20 seconds for effective cleaning. However, when it is not possible to wash your hands or other high-touch surfaces, alternate methods of sanitisation and disinfection can be effectively applied instead.
Sanitisation is the process of making both inanimate and living surfaces bacteria-free; reducing the overall number of pathogenic microbes. Sanitisers have a broad and immediate action against a wide range of germs; quickly reducing overall numbers.
According to Gold and Evva, (2020), Ethanol has been known for its antimicrobial properties since 1888 and with the ease of availability and proven effectiveness in reducing microbial load, it has become one of the most common sanitisers in the world. Alcohol is an amphiphilic chemical, which means it has the properties to interact with both hydrophilic and hydrophobic molecules. Microbes, including bacteria and viruses, are often enveloped in a lipid bilayer membrane; alcohol interacts with this membrane to destabilise its integrity, destroy the cell structure and kill the germs. Most alcohol-based sanitisers contain isopropanol, ethanol, n-propanol, or a combination of two of these compounds; at 60% to 80% concentration. Anything with less than 60% alcohol is ineffective as a germicide because of its high water content. Whereas, any sanitiser solution with an alcohol content above 80% is likely to evaporate too quickly before it can effectively eliminate germs on a surface.
Non-alcoholic sanitisers usually contain Benzalkonium Chloride, a quaternary ammonium compound, as the active ingredient. It is non-flammable, and relatively non-toxic at the concentrations used in sanitiser solutions. However, as quaternary-ammonium-compound-based hand sanitisers are not commonly used in healthcare, they have yet to gain the same level of credibility as their alcohol-based counterparts.
Disinfection is the process of eliminating many or all pathogenic microorganism with the exception of bacterial spores from inanimate surfaces. Disinfectants have a stronger effect than sanitisers and requires dwell time to be effective against microbes; meaning they must remain on the surface for a certain period of time to successfully eliminate pathogens that are present. However, many disinfectants can be weakened by the presence of organic matter such as living tissue or faeces, highlighting the importance of cleaning as part of the decontamination process.
According to the CDC, low-level disinfectants can kill most vegetative bacteria, some fungi and viruses in approximately 10 minutes; whereas intermediate-level disinfectants are effective against mycobacteria, vegetative bacteria, viruses and fungi, but not necessarily bacterial spores. A few disinfectants can destroy these spores with prolonged exposure times of 3 to 12 hours, while other high-level disinfectants, such as 2% glutaraldehyde, can do so in a much shorter exposure time of 20 minutes.
Isopropyl alcohol is categorised as a low-level disinfectant and is effective for non-critical and general decontamination. Pre-moistened (isopropyl) alcohol wipes are a common surface disinfectant, extensively used in healthcare, pharmaceuticals, and medical device manufacturing industries. Providing the workforce with these wipes could ensure additional decontamination of common surfaces and equipment between each use.
Furthermore, the EPA released a list of disinfectant products that can be used to kill SARS-CoV-2 on everyday surfaces. Not every compound on the list has been tested against the COVID-19 bug; they are, however, expected to be effective because they demonstrate efficacies against other strains of human coronaviruses or other hard-to-kill virion particles. Decision makers can consult this list to make informed decisions for the disinfection needs at their facilities.
Sterilisation is described as a process of decontamination that eliminates all forms of pathogenic microbes on a surface, through the combined use of chemical application, heat, and / or pressure.
Steam sterilisation is one of the most widely used and dependable methods of sterilisation during which, the four parameters – steam, pressure, temperature, and time, work in unison to provide effective biocidal activity. It is carries out at 121° C or 132° C; and it is non-toxic, inexpensive, and rapid.
Dry-heat sterilisation, on the other hand, is only used for materials that are impenetrable to moist heat or can be damaged by it. While dry-heat sterilisation is a slow process, 170° C for 60 to 120 minutes, or 150° C for 150 minutes, it is also non-toxic, environmentally friendly, cost-effective and easy-to-implement.
Ethylene oxide (ETO) has been used as a low-temperature sterilant since the 1950’s for temperature and moisture-sensitive supplies. Mixed gas ETO sterilisation using Chlorofluorocarbons (CFCs) was replaced with alternate technologies, such as 100% ETO and ETO with carbon dioxide in healthcare environments after the Clean Air Act was passed in 1995. However, sterilisation via hydrogen peroxide, vapor phase peracetic acid, gaseous chlorine dioxide, ionising radiation, and pulsed light are routinely used as low-temperature sterilisation alternatives in other industries.
Ionising radiation is primarily performed by cobalt 60 gamma rays or electron accelerators. It is most suitable for large-scale sterilisation objectives. Vaporised Hydrogen Peroxide (VHP®) also offers several appealing features, including rapid cycle time, environmentally safe by-products and good material compatibility.
Ozone is produced when oxygen atoms loosely bond with a dimeric oxygen gas molecule. This powerful oxidant can then destroy microorganisms at room temperature. The method is compatible with a wide range of commonly used materials including stainless steel, titanium, ceramic, glass, silica, PVC, Teflon, silicone, polypropylene, polyethylene and acrylic. However, the ozone sterilisation devices, currently in the market, are not suitable for the sterilisation of large spaces.
The term sterilisation is intended to convey absolute meaning, unfortunately it is often misused and interchanged with the term disinfection. Therefore, it is of utmost importance that while choosing a sterilant, you thoroughly investigate the active ingredients or the credibility of the sterilisation technique against your own purposes and limitations.
Securing the right products and establishing a proper decontamination procedure will go a long way to preventing the spread of diseases amongst your team members at work. However, it is equally important to ensure that every member of your staff has a good understanding of the need for hygiene at the workplace. Putting up clear informational communication and arranging necessary training to educate your staff members on the importance of personal and workplace hygiene could also benefit your workforce and play an important role in preventing the spread of COVID-19 or any other illnesses that might otherwise easily spread.
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