What is deep cleaning and how does it work?
Original post by Doug Powell on barfblog.
It’s a phrase that is bandied about whenever there is an outbreak of foodborne or other microbiological thingies: We didn’t just clean, we did a deep clean…. But, what does a deep clean actually mean?
Andrew Brown of The Canberra Times had a go at the subject of deep clean.
While cleaning normally focuses on removing visible signs of mess through vacuuming, dusting and wiping things down, deep cleaning goes one step further.
Deep cleaning involves the use of disinfectant and other chemicals to remove any traces of germs and viruses, including coronavirus.
Part of deep cleaning also involves wiping down every surface in a venue, regardless of whether it has come into direct contact with an infected person or not.
A particular focus is high-frequency touch points, such as light switches, door handles, taps and areas like computer terminals or communal kitchens in office spaces. While high-grade disinfectants are used as part of deep cleaning, other chemicals can also help to remove traces of the virus.
Anthony Bailey, ACT Education Directorate senior director of school cleaning services, said a fine-mist spray was also used as part of deep cleaning efforts in Canberra schools.
“With the fine-mist spray, the chemical settles in areas you can’t normally reach,” Mr Bailey said. “It’s unlikely people are touching those surfaces, but it’s all about elimination.”
One of the ACT’s schools, Lyneham High School, required deep cleaning in March after a student attended the campus while potentially contagious with coronavirus.
Mr Bailey said swab tests of surfaces for traces of coronavirus were also carried out before students and staff members could re-enter the school.
One of the main ways coronavirus has been able to spread is through being picked up by humans after they come into contact with the virus on surfaces. Research is being carried out in a number of places on how long exactly the virus can linger on surfaces and lead to further infections.
Early findings have determined strains of COVID-19 can stay alive for several hours or even days, depending on the type of surface it lands on.
According to a recent study from the New England Journal of Medicine, the virus can last for four hours on copper surfaces, while it can stay on cardboard or paper for 24 hours and up to three days on plastic and stainless steel.
A similar study published in The Lancet had slightly different findings, with the virus lasting for three hours on tissue paper, while traces were still detected on cloth and wooden materials for two days.
Associate professor at the Australian National University medical school, Sanjaya Senanayake, said the Lancet study also found the virus could stay on surfaces such as surgical masks for up to one week after they were worn.
“The two studies were slightly different in the types of materials that were used, but clearly the virus can survive on surfaces for some time,” associate professor Senanayake said. “Maybe after half an hour on a surface, there’s a lot more virus on it, and therefore people are more likely to be infected if they come into contact. By the seventh day, the virus might still be around on surfaces, but may not be enough to cause an infection.”
At its core, deep cleaning is about attacking the virus at every possible location it could be in a building. However, for a virus that’s devastated nations around the world and locked down cities across Australia, associate professor Senanayake said COVID-19 was remarkably easy to kill.
“It’s an enveloped virus, meaning it’s got an outer covering and it’s very susceptible to things,” he said. “Despite it being this terrible thing that’s caused a pandemic, it’s easy to kill with things like standard detergents as well as soap and water.”
Using things like detergents might be enough to kill off the virus, but associate professor Senanayake said using just disinfectant or chemicals on their own might not have the desired effect.
“If you put just disinfectant on those areas, some of the virus particles might be able to hide,” he said. “Surfaces should be cleaned with detergent first and then disinfected after that with something like 70 per cent alcohol or bleach.”
It should also be noted that any cleaning of surfaces suspected of having traces of coronavirus should be done with personal protection, such as a mask.
COVID-19 Within the Work Premises
A COVID-19 certified decontamination program should be conducted by a third-party decontamination cleaning company. The company shall:
Be fully equipped to carry out a large range of control methods on site
Include all areas of the work premises for the decontamination: floors, walls, internal and external door handles, toilets, bathrooms, meeting rooms, stairwells, corridors, equipment, storage areas, kitchens, staff rooms, locker rooms and any other accessible and high touch areas
Depending on the size of the premises, clean-up shall take between 1-3 days
Upon completion of the job, the cleaning company should supply a comprehensive health certificate that may be required to be forward to the health department upon request.
To support the health certificate, swab tests of surfaces should also be carried out by a NATA-certified laboratory.
