Most diseases spread by direct contact with others. To make you sick, a pathogen needs to find its way into you in sufficient numbers to survive the initial assault of your immune system, and then multiply.
However, this doesn't mean transmission doesn't occur via surfaces. Some pathogens are better suited for surface transmission than others; tinea, the fungus that causes athlete’s foot, survives on warm, moist surfaces like showers. In the right conditions, some microorganisms such as bacteria can even form biofilms (e.g. dental plaque).
Other pathogens, such as viruses, aren’t as suited to this pathway. Since they are dependent on a host, virus survival on surfaces is more limited.
Porous vs Non-Porous Surfaces
There is evidence to support the fact that hard, non-porous surfaces such as tables, door handles or toilets are far more effective in transferring germs from their surfaces to hands, than porous surfaces like fabrics.
Germs hide in gaps on porous surfaces, making them less able to spread. When these surfaces are wet, it can create a more favourable environment for microorganisms, but the porosity can mean that the moisture is drawn away from the surface, making it less likely to be transferred from surface contact. On non-porous surfaces like steel or plastic, the germs remain on the surface and are easy to have contact with, making them the most efficient in transferring and thereby transmitting disease.
Surfaces In Our Kitchens
Foods like raw meat, poultry and seafood have a high risk of cross contamination, enabling the transfer of harmful bacteria like salmonella via surfaces to other food items. To be on the safe side, food and health regulation agencies recommend that you use plastic or glass chopping boards for these foods, or have one chopping board and knife for meat and fish and another for everything else. Running chopping boards through a dishwasher at high temperatures helps disinfect them.
Knife grooves and worn areas on plastic chopping boards can become a breeding ground for microorganisms, and pores in old wooden chopping boards can become clogged and lose their food safety benefits.
Other Surfaces We Come Into Contact With Often
When it comes to surface transmission, non-porous surfaces that we touch often but rarely clean remain a concern. These include door handles, lift buttons and other surfaces in high-traffic areas that are touched by multiple strangers.
Surfaces like phone screens that are in contact with skin oils and other germs (such as those found in bathrooms) are more likely to enable pathogen transmission, so although if you don’t frequent hospitals or other healthcare facilities, it’s less likely that your mobile phone is contaminated with disease-causing pathogens, it is still very possible.