What to look out for when buying an effective disinfectant

by WeCare Pharmacy Network
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Johannesburg, 29 July20: With the arrival of the novel COVID-19 virus, shoppers are finding shelves and in store displays stacked with more hand sanitisers and general disinfectants than ever before. But how exactly does one know what to choose amongst the myriad of options available?

According to Dr Jacques Snyman, Chief Executive Officer of Medical Specialist Holdings, the massive choice of disinfectant products on the market makes it important to educate consumers about what constitutes a good sanitiser and inform them about what to look out for when navigating this increasingly diverse range of products.

Dr Snyman says: “Not all sanitisers and disinfectants are created equal and consumers need to educate themselves properly before filling their shopping baskets with potentially ineffective products that look good on the shelf but do little to eliminate the dangers against which people need to guard.”

“A disinfectant is defined as a chemical substance which has the ability to destroy harmful micro-organisms, such as bacteria, viruses, moulds, mildews and fungi, especially on non-living objects as well as provide effective protection when used as hand sanitation devices.1 Disinfectants must be effective and safe regardless of any other compounds present during use. They must also be stable in both diluted and concentrated forms.” says Dr Snyman.

Dr Snyman adds that most shoppers were probably unaware that sanitisers even existed prior to the COVID-19 pandemic, however these products aren’t necessarily new and their ability to curtail the spread of viruses and even organisms that cause the common cold, influenza and even TB and other infectious diseases has been well documented. 

The highly respected United States Environmental Protection Agency (EPA) classes disinfectants as either high, intermediate or low. High-level disinfectants kill almost all organisms while intermediate-level disinfectants are able to kill mycobacteria (a group of bacteria which includes the causative agents of leprosy and TB), most viruses as well as bacteria.  Finally, low-level disinfectants kill just some viruses and bacteria.

“A good disinfectant should, therefore, be active against a broad spectrum of germs, spores, and fungi and display slight to moderate efficiency in the presence of organic matter. It must be safe for both humans and animals, kind to the environment and leave no damage or odour. It must also be non-corrosive, affordable, and suitable for straightforward usage,” says Dr Snyman.

Commonly used disinfectant categories include alcohols, alkalis, aldehydes, oxidising agents (chlorine bleaches), phenols, and quaternary ammonium products. In many cases, two or more different disinfectants are combined to improve activity or application properties.

Dr. Snyman says that disinfectants cannot merely be mixed or used in combination without the proper knowledge of each mechanism of action. For this reason, it is best to stick to trusted brands rather than simply selecting the cheapest product on the shelf.

“It’s always a good idea to read the label before buying an unknown product and the one thing which you must always take note of, is the concentration of the alcohols used in a product,” says Dr. Snyman.

“Alcohols between 60-90 % are considered to be good general disinfectants. However, the usefulness of alcohol as a single agent decreases as the concentration used drops below 50 %. It is important to understand that higher concentrations of alcohol within a disinfectant do not necessarily generate more desirable effects against bacteria, viruses, and fungi,” says Dr. Snyman.

Dr Snyman also stresses that using a good disinfectant doesn’t mean that you don’t have to wash your hands. Instead, soap and water actually go hand in hand with disinfectants because cleaning with water and the use of soap enables the physical removal of dirt and grease. When cleaning with soap, one simply moves pathogens from one surface to another. Disinfection allows for the elimination of pathogens from these surfaces and ensures that they cannot reproduce.9

Most importantly, proper hand washing removes organic or non-organic material which may impair the efficacy of the disinfectant being used. For example, disinfectants may bind to something on your hands and fail to kill the germs you wanted to eliminate. That means, for disinfectants to be most effective, your hands should be clean before disinfectants are used.

Dr. Snyman says skin safety must be a top priority. “Always use a disinfectant that is more friendly to your skin. Some products not only eliminate 99.9% of bacteria and fungi but are dermatologically approved, pH neutral for skin, and have added moisturizing ingredients such as glycerin and aloe vera oil,” says Dr. Snyman. If you use products without these ingredients or have to use a number of different sanitisers during a shopping trip, remember to apply good hand lotion to prevent your skin from cracking or peeling as this can provide hiding places for germs.

Dr Snyman offers the below tips when it comes to choosing a disinfectant:

  1. First, look at the tests done and accreditation status of the product – i.e. SABS or similar registration – as this confirms the validity of claims about the antimicrobial activity. The product must submit proof of efficacy to obtain this accreditation.
  2. Don’t be too fixated on the concentrations of the various ingredients as this means little if not understood and evaluated in the context of the product’s intended use e.g. hand sanitisers often contain additional products to prevent excessive drying of the skin while others need to be less corrosive to the surface they must be used on. All these properties are taken into consideration when products get their registration for use.
  3. Only use a product for its labelled use as this will guarantee successful protection.
  4. Select products which are non-irritating and do not trigger allergies or eczema if you are prone to be sensitive to colourants and fragrances. If your skin is particularly sensitive, use protective gloves when scrubbing and disinfecting surfaces.
  5. Shop with a conscience. A sudden surge in the use of soaps and disinfectants could potentially harm the environment through polluting our water. As a responsible consumer, choose a product which contains biodegradable and environmentally ingredients and is not tested on animals.
  6. When you buy your sanitiser, make sure it comes from a reputable source. There are a number of well-known, South African manufacturers that are reputable suppliers of products to the South African market.

How to read labels:

An arbitrary list of ingredients will mean almost nothing to most consumers. However, for those who make a point of reading labels and the many of us who are using these products, it is important to know “what ingredient does what” according to Dr Snyman.

Alcohols: The alcohols that you’re likely to see most often on product labels are ethanol (fermented from plant products such as sugar cane), propylene (from natural gas) and isopropanol. These are fast acting disinfectants with a rapid evaporation time which leave no residue.  Alcohols may have a strong smell and can harden certain rubbers and plastics.  Alcohols are active against bacteria, fungi, and tuberculosis (TB) causing organisms. 

However, alcohols have limited activity against viruses and have no activity against spores.  Solutions with an isopropyl alcohol concentration above 91 % can kill bacteria but may require longer contact time for disinfection and thus allow spores to lie dormant without being killed.  Alcohols are also highly flammable.

Alkalis: Calcium hydroxide, sodium carbonate and calcium oxide are only a few of the disinfectants which form part of the alkali group.  Alkalis have a slower acting disinfecting time, are affected by pH and perform optimally at higher temperatures.  These agents are corrosive to metals and may cause severe skin burns as well as mucous membrane irritation.  Alkalis are active against bacteria, viruses, fungi as well as spores.  Alkalis show limited action against pathogens causing TB.

Aldehydes: This class of disinfectants includes agents such as glutaraldehyde. These disinfectants have gained wide acceptance as high-level disinfectants as well as a chemical sterilant.  It is a slow acting disinfectant which is affected by both pH as well as temperature.  It is a colourless liquid with a pungent smell and is classified as non-corrosive.  Glutaraldehyde is proven to be able to kill bacteria, viruses, fungi, and TB causing organisms as well as spores. A 2% solution of glutaraldehyde exhibits good activity against vegetative bacteria, spores as well as viruses.  Glutaraldehyde is 10-fold more effective than formaldehyde and is less toxic.

Oxidising Agents: (Halogens: Chlorine and Iodine; Peroxygen compounds): Halogen disinfectants containing chlorine such as sodium hypochlorite (bleach), calcium hypochlorite and chlorine dioxide are fast acting agents which are affected by pH and require frequent application and are inactivated by UV radiation.  These agents can corrode metals, rubbers as well as fabrics.  Chlorine halogens cause mucous membrane irritation and may release a toxic gas if mixed with strong acids or ammonia.  Chlorine disinfectants are active against bacteria, viruses, fungi, TB causing organisms as well as spores.

Phenols: Phenol disinfectants may leave a residual film on treated surfaces and can damage rubber and plastic but are non-corrosive.  Phenols are stable in storage but may cause irritation to skin as well as to eyes.  Phenols are considered toxic to animals, especially to cats and pigs.  Phenols are effective against bacteria, fungi, viruses, as well as TB causing organisms but have no effectivity against spores.

Quaternary Ammonium Compounds: Benzalkonium chloride is stable in storage and provides best activity at a neutral or alkaline pH.  Quaternary Ammonium Compounds are effective at high temperatures.  Higher concentrations are corrosive to metals and cause irritation to skin, eyes and the respiratory tract.  Quaternary Ammonium Compounds are effective against bacteria, selective viruses, fungi and spores.  These agents show no activity against TB causing organisms pathogens.4



1. Disinfectant. Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam    webster.com/dictionary/disinfectant. Accessed 11 Apr. 2020.

2. Characteristics of a good disinfectant. 2017. Safespace®https://www.safespaceco.com/characteristics-of-a-good-disinfectant/. Accessed 11 Apr. 2020.

3. General characteristics of disinfectants. Mississippi state university Extension. http://extension.msstate.edu/content/general-characteristics-disinfectants Accessed 11 Apr. 2020.

4. Characteristics of selected disinfectants. 2018. The centre for food security & public health. Iowa State University.

5. cience Clarified. “We Are Surrounded.” Scienceclarified.com. http://www.scienceclarified.com/scitech/Bacteria-and-Viruses/We-Are-Surrounded.html. Accessed 1 Apr 2020

6. Rutala, William A. “Selection of the Ideal Disinfectant.” Disinfectionandsterilization.org. http://disinfectionandsterilization.org/selection-of-the-ideal-disinfectant/. Accessed 11 Apr 2020.

7. Centers for Disease Control and Prevention (21 December 2012). “Sterilization or Disinfection of Medical Devices”. CDC. Archived.

8.Figueroa, A., Hauck, R., Saldias-Rodriguez, J. & Gallardo, R.A. 2017. Combination of quaternary ammonia and glutaraldehyde as a disinfectant against enveloped and non-enveloped viruses. Poultry science association Inc. p1-7.

9.Rose, J.B. 2013. Cleaning vs. disinfecting: what’s the difference? Water quality & Health council.

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