How Germs Spread from Surfaces
Many of us have become obsessed with the world of microorganisms during the COVID-19 pandemic. We are more aware of the surfaces we touch and who has touched them before, touchpoints such as door handles, touch screens and elevator buttons in public spaces.
Scientists have found that many potentially infectious bacteria, viruses, yeasts and moulds can survive on surfaces for longer than you might expect.
We know that diseases often spread via direct contact with other people. Germs can easily find a way out of an infected person through sneezes and coughs, but to make you sick, they need to find a way into your body in sufficient numbers to survive the initial assault of your immune system, and multiply.
Surfaces add a new level of difficulty. Germs need to land on a surface and be able to survive on it until you touch it. After that, it still has to make it from the touch point to whatever area of your body that they target to thrive.
Some germs and viruses are better suited for surface transmission than others such as the fungus that causes athlete’s foot, which survives on warm, moist surfaces like showers.
Since they are dependent on a host, their survival on surfaces can be limited.
On their own, virus numbers can’t increase on a surface—only decline.
Surface contamination is a serious issue in healthcare and other settings, where lots of people carrying all sorts of germs gather.
Cardboard, wood and cloth:
The kind of surface matters. A recent review of the scientific literature found that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes COVID-19, can survive on different surfaces for different amounts of time.
On cardboard, it can survive for up to 24 hours. “I don't think that's likely to be a major source of infection,” said Australian immunologist Professor Peter Doherty in a recent interview, “but it's something you just might keep in mind when you're taking hold of the pizza box.”
Surface porosity might be the key. Viruses are some of the tiniest biological organisms known.
Like a golf ball rolling into a field of holes, they might sink into porous materials—like cardboard, wood or cloth—seldom to be seen again.
It’s all about what is available on the surface. If germs get sucked into a porous surface like wood, they might not be able to transfer to anything you place on the surface. Moisture is also drawn away from the surface, which makes it less friendly to germs and viruses.
Items in you home such as old chopping boards of any material should be replaced. Knife grooves and worn areas on plastic chopping boards can become a breeding ground for microorganisms. Pores in old wooden chopping boards can become clogged and lose their food safety benefits.
Steel, plastic and touchscreens:
In coronavirus studies, the most resilient viruses took up residence on non-porous plastic and steel. Infectious particles have been detected on both surfaces for up to 72 hours.
Because virus numbers can’t increase on surfaces, every hour that passes between the virus landing on a surface and you touching it decreases the chance of you getting sick. Conditions such as sunlight and high humidity can also cause harm to the virus.
When it comes to surface transmission, non-porous surfaces that we touch often but rarely clean remain a concern.
You are likely to be aware of door handles, elevator buttons and other surfaces in high-traffic areas touched by multiple strangers. But at this very moment, you might be staring at one surface to which you haven’t given a lot of thought.
They are always in our hands or being passed around to show things to other people. Many of us keep them with us when we eat, sleep with them and even go to the toilet. A lot of what we touch is therefore likely to end up on our phones.
A 2009 review of mobile phones as a carrier of disease-causing bacteria found that up to a quarter of healthcare workers’ phones studied were contaminated with bacteria.
If you don’t frequent hospitals or other healthcare facilities, it’s less likely that your mobile phone is contaminated with disease-causing germs—but it is possible. Surfaces that are ‘primed’ by skin oils and other gunk are more likely to enable pathogen transmission.
As the restrictions lift and we return to the outside world, be mindful of what you touch.
Take a look at our self cleaning products for some of these high traffic touchpoints and make a difference in your home or workplace.