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April 2018

Fact or fiction: old = dirty

Written by Nicole Horne
Cleanliness and Hygiene

Have you ever come across an item and thought it was dirty, just because it looked old?

How about that noisy blender your mom always used to make milkshakes, that has yellowed with age and looks absolutely filthy! Or how about your grandparents’ faithful old pot they still use to make your favourite Sunday dish? I know what you are thinking;  “how can it be okay to still eat from that?”

The perception of dirt

When we think about dirty objects, we often equate dirt with grime or dust.

It’s common practice (especially amongst mother-in-laws) to run your fingers over a surface and to use the amount of of dust as a measure of cleanliness.  I always imagine a health inspector wearing white gloves, running his fingers across the top of a cupboard and declaring an establishment unworthy of a star rating. We often think that just because objects are old (and possibly dusty) they must be dirty...

The compounds normally found on old items i.e. dust, contain a number of elements such as plant pollen, organic compounds from outdoor soil, dead skin cells, textile and paper fibers which is gathered onto an object like a basket with dirty laundry. Grime - on the other hand - may be ingrained onto the surface of an object.

There is a big difference - from a hygiene perspective - between dirty as referring to weathering, grime or dust particles, and the connotation of dirty as referring to an environment where bacteria and viruses thrive. Unhygienic surfaces that can cause us to feel unwell or ill is where dirty becomes concerning.

Type of surfaces that attract dirt and bacteria

When we look at what attracts bacteria, and the studies done around the 5 second rule, contamination of food comes down to three variables;

  1. The type floor surface (dry vs damp)
  2. The type of food (food that contains higher levels of moisture versus others that don’t)
  3. The length of time food comes in contact with surfaces (the longer time being the culprit)

All three of these greatly determine the transfer of bacteria. If we apply this principle to the surface of everyday objects, moisture levels and the length of time bacteria spends on a surface should therefore also have an impact on the levels of bacteria found on an object.  

In a previous blog we investigated the upcoming trend of antimicrobial surfaces that repel bacteria and rougher surfaces containing nanoscale pores that make it difficult for bacteria to attach. Surprisingly, we might think coins are highly unhygienic, but Philip Tierno, director of microbiology and immunology at New York University Langone Medical says that because of their antimicrobial properties, metals such as copper, nickel and silver don’t support bacteria.

Did you know that some bacteria hotspots are places and things you may not have ever have thought about? Read our blog, 7 Bacteria hotspots we bet you didn’t know about to find out more. 

Read the blog

Thus the surface type of an object greatly determines its propensity to become a bacterial breeding ground, and this is applicable to both old and new surfaces.

The most common culprit for bacterial transfer

You may look at the old rag lying in the corner of the garage and think “Yuck, I’ll never in my life touch that with my hands”. You’d be surprised to find that it is those very hands that are the biggest source of bacteria transfer, not the rag!

Did you know that 80% of germs (such as E.Coli, Salmonella and diarrheal infection) are spread through touch?

Hands are the perfect breeding ground for bacteria as they contain the four key ingredients to host a big bacteria party. Disease-causing bacteria thrive in temperatures close to body temperature, areas containing moisture, environmental oxygen and environmental ph similar to that of the human body. So next time be sure to look at your own hands before you point fingers at an old object in disgust.

So do you still think shiny equals clean?

Because hands are the main vehicle for transferring bacteria,  (new) household objects that we use regularly may actually be dirtier than the dreaded old rag silently waiting in your garage. We tend to think that items such as our mobile phones, laptops and desks - which are new and on-trend - are less likely to contain germs. However these items can be seen as bacteria’s working headquarters, with frequent contact being the main source of bacterial transfer. In fact, that dusty old object that hasn’t been used in years may not miss your frightful touch.

Did you know that a mobile phone can harbour as many as 25 000 germs per square inch? Find out how clean other items are in our blog Rank these by their cleanliness [Quiz].

What it all comes down to

As we mentioned above there are various factors that can impact an object’s level of hygiene; mainly the type of surface (smooth versus rough), moisture levels, temperature, and of course cross contamination in which our hands are the key source of spreading bacteria.

Even though objects may seem clean, we don’t really know what is lurking on the surface and what has come into contact with it before we use it; whether old or new.

It’s important to keep in mind that hygiene is everyone’s responsibility, so ensure that you wash your hands frequently and sanitise those objects that come into contact with hands on a regular basis.

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Nicole Horne

Nicole Horne

Nicole is a Digital Marketing Executive at Rentokil Initial Hygiene in Johannesburg. A self-proclaimed germaphobe, her love for hygienic environments and curiosity of all things “beneath the surface” fuels her enthusiasm for writing about the impact of germs in the workplace. She is passionate about creating awareness and sharing her knowledge on the impact of good hygiene practices. Follow Nicole on Twitter and LinkedIn for updates on the the good, the bad and the germy.

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