Choosing a disinfectant or sanitiser

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Any one of us can walk in to a supermarket and purchase a disinfectant/sanitiser in the confident belief that this product will protect us and our family.

However, there are a number of important issues that should be taken into consideration. For example, is that product effective on the target microorganisms? And how quickly does it kill them?

Target microorganisms

Typically, an anti-bacterial sanitiser will offer 99.9% kill of bacteria, including, Salmonella, Listeria, Influenza and E.Coli. The main concern at the moment is, of course, COVID-19, a virus, so an anti-bacterial sanitiser is not necessarily suited for this purpose.

Contact time

There are of course disinfectants that have a proven efficiency against viruses, but in assessing that efficiency, it is important to note the contact time required, how long does the product have to be in contact with the virus before it is deactivated? This is important because extended contact times in laboratory tests are not practical in real world situations.

During a viral pandemic, it is important that appropriate surfaces are disinfected with products that quickly and effectively deactivate all of the main problematic pathogens including viruses. This means that all surfaces that are regularly touched should be disinfected, with sufficient contact time.

Efficiency

The percentage kill for a disinfectant is another vitally important consideration. The difference between 99.9% and 99.9999% may not seem like much, but in fact, it means, for example, that certain disinfectants/sanitisers are 1,000 times more effective than a disinfectant claiming 99.9%.

Hand sanitisers

In addition to the disinfection of surfaces that are regularly touched, it is also necessary to disinfect hands, hence the requirement for frequent hand washing. Alternatively, alcohol-based hand antiseptics containing ethanol, isopropanol or n-propanol, or a combination thereof, can be employed.

According to the World Health Organisation, the main advantages of alcohol-based hand sanitisers are that they are fast-acting and broad-spectrum. Also, in a healthcare setting they can overcome the limited availability of taps and washbasins.

Alcohol solutions containing 60-80% alcohol are most effective, with higher concentrations being less potent. Alcohols have excellent in vitro germicidal activity against Gram-positive and Gram-negative vegetative bacteria and a variety of fungi.

However, they have virtually no activity against bacterial spores or protozoan oocysts, and very poor activity against some non-enveloped (non-lipophilic) viruses.

Frequent use of alcohol-based formulations for hand antisepsis tends to cause drying of the skin, unless humectants or other skin conditioning agents are added to the formulations.

However, even well-tolerated alcohol-based handrubs containing humectants may cause a transient stinging sensation at the site of any broken skin. Alcohols are also flammable, so appropriate safety precautions are necessary.

Summary

As outlined above, there a number of important issues to be considered when choosing a disinfectant/sanitiser;

Does the product have sufficient efficacy against relevant pathogens?
How fast are the pathogens killed?
What is the efficiency in terms of percentage kill?
Is the product safe for use in terms of toxicity and flammability?
Is it easy to use on all surfaces and skin?