Covid-19: De-contaminating a surface is a two-step process - people are skipping the first step
- Ridding your home of the coronavirus requires two steps: cleaning and disinfecting.
- Cleaning involves wiping down a surface with soap and a rag, while disinfecting involves applying a chemical to kill off any germs.
- A professional biohazard cleaner said people often forget that first step and spray disinfectant right away. That means their surfaces are likely still contaminated.
- For mores stories go to www.BusinessInsider.co.za.
The coronavirus spreads primarily through respiratory droplets when you sneeze or cough, but it can also linger on surfaces in your home.
To reduce your chance of infection, the US Centers for Disease Control and Prevention recommends cleaning areas that you touch often, like doorknobs, sinks, and toilets.
But cleaning a surface isn't the same as disinfecting it.
The cleaning process involves scrubbing an area with soap and water, while disinfecting means applying a chemical to kill germs.
"The most important step is the cleaning step," Cory Chalmers, CEO of the professional cleaning service Steri-Clean, told Business Insider.
His team specializes in biohazard cleaning for sites contaminated with infectious diseases. For the past month, they've dedicated themselves almost exclusively to scrubbing down places contaminated by the new coronavirus. That includes homes, cruise ships, offices, factories, and fast food restaurants.
"A lot of people spray a surface and then wipe it around right away," Chalmers said. "But you're not letting the disinfectant do its job."
That's because dirty surfaces are coated in clusters of germs called biofilm that resist disinfectants. These germs have to be removed before a chemical can effectively kill off any lingering viruses or bacteria.
Chalmers said the first step in the cleaning process should be putting soap on a rag or paper towel, then folding the towel into quarters. The towel will lift the biofilm off the surface so that only residual germs are left behind.
After you've wiped down a small surface - a couple square feet - flip the towel over and use the other side, then turn it inside out and use the remaining quarters.
"People sometimes will walk around the house with the same rag, cleaning all the surfaces. That doesn't do anything because now they're just spreading the germs around," Chalmers said. "Once that towel or rag that you're using is full of germs, it's not going to absorb anymore."
After the surface is clean, you can apply a disinfectant spray or wipe.
Chalmers said the back of every disinfectant bottle is marked with a "dwell time" - how long the disinfectant needs to sit on a surface before it kills germs. Some disinfectants take 10 minutes, while others only about 30 seconds.
The virus lives longer on certain surfaces, like glass
Depending on the type of surface, it's possible to let the coronavirus die on its own. Research from the University of Hong Kong suggests that the coronavirus can live for three hours on printing and tissue paper, but for two days on cloth.
- The virus tends to survive for much longer on glass and paper money: around four days.
But its lifespan also depends on temperature and humidity. The Hong Kong researchers found that the coronavirus lasted lasted up to two weeks in a test tube under 39 degrees Fahrenheit, but just one day under 99 degrees Fahrenheit. A group of Beijing researchers also determined that high temperature and high humidity could reduce the virus' transmission.
Since there's still more research to be done, Chalmers said cleaning and disinfecting is a safer method than waiting for the virus to die.
"When you're dealing with a new strain like this, we really don't have all the answers," he said. "I don't think we have enough factual data to know that closing up a building or an office or a room will kill that virus."
That's also why he recommends being extra cautious when wiping things down - or hiring a service to do it for you.
"There are so many companies out there from landscapers to plumbers to exterminators that are all claiming they're experts and they're going to disinfect your house," Chalmers said.
"Ask them how they're doing it. What's the process? Are they cleaning first, then applying the disinfectant? Are they testing? If they're doing all three of those, you should be safe."
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