Happy new year! It might have been two weeks since you last set foot in the office. And while your top priority is to get through the mountain of emails, it might pay to give your desk some attention before you fire up your computer.
And for some very good reasons, too. The pantry sponge, for example, may be germier than the office toilet seat.
First, the science.
While you were on your year-end break, bacterial activity in your workspace didn't stop. For instance, clostridium perfringens, the bacteria that can cause food poisoning, has a generation time or doubles in number in about 10 minutes, according to Britannica.
Escherichia coli or E coli can double every 20 minutes. In fact, if left unchecked for 36 hours, it can fully cover the surface of the Earth in a 30cm-deep layer, according to the book Alcamo’s Fundamentals Of Microbiology: Body Systems Edition. The reason why we aren’t buried in bacteria, noted the book, is because the nutrients they need to grow are limited, or the environment for growth isn’t conducive.
“Bacteria are able to grow rapidly, from several to hundreds of thousands if the environment is conducive enough, that is, a room temperature with high humidity and some surface for bacteria to attach,” said Richard Khaw, deputy director of the School Of Chemical And Life Sciences at Nanyang Polytechnic.
WHEN BACTERIA GO ROGUE
Bacteria, whether beneficial or adverse to health, were one of the first life forms to appear on Earth about 3.8 billion years ago. And they are everywhere, including in and on your body. In fact, scientists have estimated that humans have about 10 times more bacterial cells in our bodies than we have human cells, according to Phys Org.
“Most of the bacteria are found on our skin, and in our mouths and nasal passages,” said Dr Edmund Lui, who lectures at Singapore Polytechnic’s School Of Chemical And Life Sciences.
And as research has shown, bacteria is essential for your health. Digestion-aiding bacteria, for instance, doesn’t just benefit your gut – mice without such bacteria have been found to have defects in the brain that control anxiety and depression, noted Phys Org. Upsetting the bacteria balance may also lead to diabetes, inflammatory bowel disease and infections.
But with the good comes the downside of bacteria. It is interesting that some dangerous bacteria such as Staphylococcus, which can cause toxic shock syndrome, exist harmlessly on human skin. Even some strains of E coli, despite its notorious food poisoning reputation, is benign in the digestive system, according to Science Clarified.
For bacteria to cause health issues, they have to reach a certain level or infectious dose. “This refers to the minimum amount of bacteria that will make you sick,” said Dr Lui.
Different bacteria have different infectious doses. “For staphylococcus aureus, the infectious dose is around 100,000 organisms, while salmonella is 10,000,” said Dr Lui. “It also depends on the host’s immune system and the part of the body that the bacteria gain entry into.”
However, there are some pathogens that may cause illnesses even at lower counts, said Khaw. “That is why it is best to keep all these items thoroughly cleaned before the next use, especially if they will be left unattended for a while, for instance, during the holiday period,” he said.
So, what’s the healthy limit on the bacteria count then? If you’re talking about anything that comes into contact with food, including the pantry tap and sponge, as well as common-use coffee mugs, utensils and cutlery, the total bacteria count should not exceed 100,000 per gram of food, said Khaw, citing the Agri-Food and Veterinary Authority of Singapore’s guidelines.
Some bacteria are able to attach themselves on such damp surfaces to form a layer of biofilm and multiply. The biofilm formed cannot be dislodged easily by just rinsing the utensils with water.
As for items that impact the office environment and indoor air quality, Dr Khaw referenced the National Environment Agency’s indoor air quality guidelines of not exceeding 500 counts per metre cube.
WHAT ARE THE FILTHY ITEMS IN YOUR OFFICE?
There are many things that you come into contact with when you enter the office. There’s the elevator button, the door handle, the keyboard and mouse, the coffee mug and the pantry sponge, to name a few. What are you picking up as you make your way to your desk?
“A wide range of bacteria could be found, including staphylococcus, streptococcus, coliform bacteria and enterococcus,” said Dr Lui. Fortunately, they are unlikely to cause specific diseases in most cases, he added.
Typically, the more human contact an item receives, the germier it is. Another factor that determines an object’s bacteria count is its material and whether it can hold water. Explained Dr Lui: “Usually, the less porous the material, the lower the bacterial growth. If the surface is dry, bacterial growth would also be reduced.
“A quick way of preventing the bacteria’s survival rate is to coat the surface with a material that prevents attachment,” said Dr Lui. “An example is the use of silver nanoparticles or copper, which could disrupt and inactivate the protein in the bacteria and inhibit growth.
“Cutlery made of stainless steel also has the ability to harbour bacteria, but we can reduce the bacteria load by reducing the rough surface area to prevent attachment. Another area of research is to have structurally modified super-hydrophobic surfaces that prohibit bacterial growth,” he said.
Do not use one damp cloth to wipe something else without rinsing it first.
In other words, a wooden spoon may harbour more bacteria than a stainless steel one. The pantry sponge may be germier than the office toilet seat. In fact, Khaw rates the common touch zones in the office from the dirtiest to the least dirty as so:
- Pantry sponge for washing dishes
- Taps in the kitchen and bathroom
- Common-use coffee mugs
- Personal water bottle
- Doorknobs or handles
- Elevator buttons
- Keyboard and mouse
- Conference room phone
CLEAN UP GOOD
If your desk has been left vacant for two weeks or more during the festive season, it is important that all contact surfaces such as the desk top, keyboard, mouse as well as the shared and personal phones are wiped thoroughly with a damp cloth, followed by a dry cloth or paper towel, said Khaw.
However, wiping something longer does not mean that its surface will be cleaner – it is more important to wipe the entire surface thoroughly. “The cloth must also be rinsed with detergent after wiping each surface or item. Do not use one damp cloth to wipe something else without rinsing it first,” said Khaw.
If you are using disposable wet wipes and paper towels, use a new piece for each surface or item. If a disinfectant is used, go with the most effective concentration indicated on the label. “If you are using alcohol as a disinfectant, the optimum concentration is 70 per cent,” said Khaw.
“The spraying of a disinfectant is optional and only if some colleagues have fallen ill as the bacteria and viruses may be present in the office environment,” he said.
As for personal utensils such as cups, teaspoons, water bottles, and thermos flask, give them a good scrub with a (new) sponge and washing detergent, and rinse them thoroughly before use. “Scrubbing is important as some of these utensils may have been left damp, or washed but not dried properly before you left for your break,” said Khaw.
“Some bacteria are able to attach themselves on such damp surfaces to form a layer of biofilm and multiply. The biofilm formed cannot be dislodged easily by just rinsing the utensils with water. Therefore, scrubbing is a must.”
Take note to also check the sponge before scrubbing your cutlery and utensils. If you’re doubtful about its cleanliness, use a new one. “We should be mindful to change the sponge frequently, and clean it,” said Dr Lui.