How to Use Surface Disinfection to Fight COVID-19

Nowadays, we hear a lot about viruses, disinfection and sanitising in the media, but the real science is rarely explained.  

How do you protect your vulnerable residents from harmful microorganisms like COVID-19?  

We partnered with Everard Paynter of Actichem in our webinar to answer this question. 

Surface Disinfection, Explained 

Everard broke down the topic of surface disinfection into three distinct parts: 

• The problem 

The science behind microorganisms and the infections they cause. 

• The solution 

Disinfection, how it works and the effect of surface type. 

• The details 

Methods of application of surface disinfection. 

Surface disinfection is a key ingredient of hygiene in an aged care home.  

It’s not only an answer to the immediate problem of COVID-19. It’s a continual protection against infections in a facility full of vulnerable people.   

The Science Behind Surface Disinfection 

The goal of surface disinfection is to prevent infections, by targeting the cause of the illnesses. 

Pathogens. 

There are thousands of these harmful microorganisms. Microbiology classifies them into six groups, according to their composition and nature: 

• Vegetative bacteria 
• Bacterial spores 
• Mycobacteria 
• Moulds 
• Viruses 
  – Unenveloped 
  – Enveloped   

Types of Harmful Microorganisms 

Lifespans of Microorganisms 

Lifespans are defined as how long microorganisms usually survive outside of a carrier. This is important, because the longer a germ stays alive on a surface, the more likely it is to transfer to a carrier and cause an infection. 

Knowing the factors that can decrease lifespan of microorganisms is an important tool to reduce infection risk in aged care facilities. Some key environmental factors that decrease lifespans include: 

Table 1: The Effect of Environmental Factors on Lifespans 

Key Factor	Effect on Lifespans
Organic waste	Increases lifespans
Sunlight (UV)	Decreases lifespans
Extreme temperatures	Decreases lifespans
Surface type	Smoother surfaces increase lifespans for viruses Porous surfaces increase lifespan for bacteria

A critical takeaway: 

Keeping surfaces clean (removing organic waste) limits the chances of germs surviving on those surfaces. 

Resistance to Surface Disinfection 

Here are the microorganisms in order of decreasing resistance to environmental factors and to disinfectants: 

• Bacterial spores 
• Mycobacteria 
• Unenveloped viruses 
• Mould 
• Vegetative bacteria 
• Enveloped viruses 

SARS-CoV-2, the virus that causes COVID-19, falls into the enveloped virus group. So, it’s one of the easiest microorganisms to neutralise when outside its human carrier.    

In other words, SARS-CoV-2 is easy to kill, but easy to spread. 

This is why surface disinfection plays such as important role in the fight against infection. 

What is Surface Disinfection? 

Surface disinfection is using a chemical to kill the microorganisms which could cause infections.  

First, it’s important to define the various kinds of chemicals we use to kill microorganisms, as these are often confused. 

Table 2: Types of Disinfectant and Their Uses 

Type of Disinfectant	Use
Sterilant	Sterilizing surgical implements and therapeutic instruments.
Hospital Grade Disinfectant	Neutralising common healthcare infections caused by enveloped viruses, bacteria and mould. These are verified by the TGA and are designed to provide reliable service in healthcare environments.
Commercial Grade Disinfectant	Neutralising enveloped viruses, bacteria and mould. These do not have to meet the same stringent testing as the hospital grade disinfectants and are more suited to lower risk, public areas.
Sanitisers	Disinfecting in food preparation and kitchen facilities.
Skin Care Sanitisers	Killing germs on hands and skin. These are mainly used in general and low risk healthcare settings.
Antiseptics	Killing germs in wound care and surgical applications.

Author’s Note: 

When you’re using disinfectants, it’s essential to use them exactly as per the instructions. This includes: 

• using the disinfectant at the correct strength 
• allowing stipulated dwell times  
• not using disinfectants past their expiry date 
• never mixing disinfectants with any other chemicals, and storing solutions in sealed, supplier provided bottles.  

The Effect of Surface Type 

We saw in Table 1 that surface type affects lifespan. 

Similarly, surface type has a significant impact on disinfection.  

Smooth surfaces are difficult to fully wet and keep wet (to ensure dwell times and full disinfection). On the other hand, rough and porous surfaces have difficult to access pores (which can prevent all the surface from being disinfected).  

Your disinfectant needs to have excellent wetting and penetrating ability. But, you must team this up with wiping to dislodge any remaining organic matter. 

Author’s Note:  

Touch points are mostly smooth surfaces. They hold microfilms of skin oil which need to be broken through with wiping to guarantee effective disinfection. Even hydrophobic surfaces such as phone screens hold tenaciously onto oily skin residues. 

How Do We Use Surface Disinfection? 

Now we know the key points to consider when you’re choosing a disinfectant, how do we apply this knowledge to an aged care facility? 

Cleaning Before Surface Disinfection 

The first and most important thing when disinfecting surfaces is to clean first. 

A clean facility is 90% of the way to complete infection control, because organic matter (dirt) on surfaces has two massively negative factors:   

1. Organic matter harbours microbes, feeding and housing pathogens.  

2. Organic matter deactivates disinfectants by getting in the way of the chemical.   

So, cleaning is the first thing to tackle, especially in high-risk and high contaminant areas such as showers and washrooms.  

Methods of Surface Disinfection 

There are two methods you should use side-by-side when disinfecting most surfaces: 

1. Spray and wipe 

2. Fogging/spraying 

Spray and wipe 

You need two steps to clean dirty surfaces and localized decontamination such as blood or urine spills. Always clean the area first (preferably with the disinfectant) and then disinfect in a second step.   

For visually clean surfaces, you can clean and disinfect in one step. Always wipe with a cloth to break through any micro-oils on the surface. 

Everard’s pro tips on the spray and wipe method: 

• The most effective cloth for disinfection is chux cloth. It doesn’t absorb the disinfectant moisture and provides good agitation. 
• Don’t use microfibre cloths with disinfectants. Microfibre cloths will work against the biocide chemistry due to conflicting charges. They’ll also absorb the moisture, taking it away from the surface.  
• Pre-moistened disinfectant wipes can also be useful as an alternative to spraying. 

Fogging/spraying 

In bio-decontamination situations, fogging or micro-spraying is an effective disinfection method.  

Depending on the disinfectant used, most surfaces can be left to air dry. However, touch points must be wiped with a premoistened cloth for disinfection to be effective.  

If you need to conduct a deep clean, research options to buy your own fogger or sprayer. It’s also worthwhile to get quotes from outside contractors. 

Author’s Note 

The most effective method when wiping is to allow the surface to air dry, as opposed to wiping dry. 

Air drying provides the dwell time required for neutralizing germs. It also leaves a microfilm of residual biocide on the surface for extended protection. 

The Results from Surface Disinfection 

Regular, effective cleaning and disinfection is a lot less expensive than an outbreak. 

You can save money on surface disinfection by: 

• Using professional dispensing systems,  
• Keeping equipment maintained, 
• Outlining clear, simple processes, and 
• Preventing wastage with best practices. 

Most importantly, effective surface disinfection will protect your elderly residents from potentially deadly pathogens.