9 Dos and Don’ts of COVID-19 Disinfecting

About a 8 minute read

By: Carey Rossi

Here’s how to use everyday cleaners safely and correctly to ward off germs.

There’s a reason why the cleaning section of your local grocery store has likely been empty: New Zealanders are disinfecting their homes in huge numbers during the COVID-19 pandemic. “Any time there’s a change in normal routine, that’s when we see increased risk of accidental exposure,” says Dr Daniel E. Brooks, Medical Director of Banner Poison and Drug Information Center.

Given the current environment, with New Zealanders having been confined to their homes for weeks, day after day, it’s especially important to keep an eye on how we’re using these powerful cleaning chemicals. Now that we are allowed to venture out into the community again, its especially important we understand the correct way to keep ourselves protected by using correct hygiene measures and cleaning products safely.

Do we really need to clean so much?
Basic hygiene measures are the most important way to stop the spread of infections, including the 2019 novel coronavirus (COVID-19). Basic hygiene measures include:

  • hand hygiene – that is, washing hands regularly with soap and water, or cleansing with hand sanitiser
  • staying at home if you are sick
  • coughing or sneezing into a tissue or your elbow and then performing hand hygiene
  • cleaning surfaces regularly.

It’s normal to want to clean as much as you can during the pandemic, but do we need to scour our entire home?

Every single surface doesn’t need to be disinfected, notes Elizabeth Scott, PhD, associate dean and professor at the College of Natural, Behavioural and Health Sciences at Simmons University.

Instead, Scott recommends an approach called “targeted hygiene,” which entails focusing on areas that are most involved in the transmission of disease. In layperson’s terms, that means addressing common-touch surfaces such as:

  • Counters and tabletops
  • Appliance surfaces
  • Doorknobs
  • Light switches
  • Bathroom fixtures and toilets
  • Phones and tablets
  • Computer keyboards
  • Remote controls
  • Bedside tables

And if any other surfaces become visibly dirty, disinfect them, too, just to be safe.

Be careful to not use the same cloth with a ‘cleaner’ on multiple surfaces, or with a ‘disinfectant’ on a dirty surface as it may also transfer organisms from one place to another, rather than stamping them out.

“The organisms might be moved around on the surface or be transmitted via the cloth used. A fresh cloth or a disposable wipe would be better to use,” said Simon Swift, Associate Professor of Microbiology and Infectious Disease in the School of Medical Sciences at the University of Auckland.

Cleaning vs. disinfecting
Our supermarket shelves contain the same types of cleaning products to fight the virus as listed by the WHO, but they might have different brand names.

Swift said when shopping for cleaning products consumers should: “Check the product says it is antiviral, and then that it contains hypochlorite (the main active ingredient in bleach), or a quaternary ammonium chemical like benzalkonium chloride​, or activated hydrogen peroxide. “The main brands will have a product in this space.”

The terms cleaners and disinfectants might be used interchangeably and not necessarily correctly, or to mean the same thing each time. The important difference to remember is that a cleaner removes ‘dirt’ and anything else from the surface, but might not inactivate viruses or kill bacteria.

Whereas, “a disinfectant will destroy the micro-organism, but it won’t be as effective if there is dirt around, so it is advised to clean the visible dirt away first, and then to disinfect,” said Swift.

Do clean areas with soap and water before disinfecting—and rinse after. Depending on the surface you’re disinfecting, it’s often a good idea to rinse with water afterwards. For example, bleach and peroxide can discolour or damage certain types of countertops if the chemicals are left to stand on them. Because bleach can corrode metal, it’s also advisable to use other products on faucets and stainless steel.

Do follow directions on cleaners and disinfectants. There are comprehensive instructions on all cleaning products for sale in New Zealand which will help you use products safely and effectively. Be mindful of what kind of surface you are disinfecting. You don’t want to damage it says Microbiologist Dr Siouxsie Wiles who urges Kiwi’s to follow any instructions, and definitely don’t mix disinfectants together as you could end up with all sorts of dangerous chemical reactions happening.

Unsure of how to handle electronics? Wipes or sprays containing at least 70 percent alcohol can disinfect screens. Just remember to dry your gadgets thoroughly so liquids don’t remain on them.

Don’t use disinfectants in close spaces, like closets. Exposure to cleaning product fumes can contribute to respiratory distress. To prevent this, make sure there is a good amount of ventilation where you’re cleaning. If there isn’t a window that can be opened, consider running a fan to promote air movement.

Do wear rubber gloves. They help protect your skin from harsh chemicals. Wash your hands with soap and water for 20 seconds after you take the gloves off.

Don’t disinfect foods. “Even before COVID-19, people were cleaning food or fruits with stuff like hydrogen peroxide, and all of that is completely unnecessary. There’s no science behind it,” Brooks says. “It’s potentially harmful. Cleaning fruits and vegetables and foods with hydrogen peroxide does not promote health.”

That said, if you have a wooden or plastic cutting board that can’t be placed in the dishwasher, you can disinfect it with a solution of 1 tablespoon of unscented chlorine bleach per 5L of water (more on mixing ratios below). Saturate the surface with the solution, let it stand for several minutes, rinse thoroughly with water, then air dry or dab with paper towels.

Don’t use vinegar solutions to disinfect. “There is plenty of evidence that so-called home remedies such as vinegar and water are not effective at disinfecting inanimate surfaces,” Scott says. “Using them can leave people with a false sense of security.” Although some research suggests that vinegar cleans surfaces and helps kill some bacteria, it doesn’t do so as effectively as commercial cleaners.

So, if you’re cleaning things like mirrors, break out the vinegar solution. But, Scott notes, “to safely and effectively disinfect an area such as a food prep surface or a common-touch surface, the recommendation is to use the appropriate dilution of household bleach or other disinfectant such as Lysol, following the label recommendations.”

Don’t mix chemicals. “Combining chemicals poses a risk of unknown synergistic effects,” Brooks says. In other words: “You could actually start a chemical reaction that generates heat or gas, which could lead to eye injury or pulmonary or lung injury.”

Some common chemicals you should never mix include:

  • Ammonia (often found in glass cleaner and some paints) and bleach
  • Bleach and any acid (including vinegar; any lime, calcium or rust removal products; glass or toilet or drain cleaners; and dishwashing detergents)
  • Bleach and rubbing alcohol
  • Hydrogen peroxide and vinegar
  • Hydrogen peroxide and bleach

Simply put, don’t mix any cleaning chemicals or disinfectants with anything besides water.

Do dilute concentrated products with water. “The safest way to do it is to add the cleaning agent into water,” Brooks says. Many product labels explain the product-to-water ratio to use, but for a basic bleach disinfecting solution, mix 5 tablespoons (or 13 cup) of bleach for each gallon of water, or use 4 teaspoons of bleach per quart of water. Just remember to use your solution within 24 hours. The bleach will fade in strength and can cause certain plastic containers to deteriorate in the meantime.

Do use common sense. “You can prevent injuries and exposures just by using your head,” Brooks says. Needless to say, only use household cleaners and disinfectants on surfaces in your environment, and never eat, drink or inject them. And always keep chemicals away from children.

If you have any questions about the safety, use or handling of any chemicals, or if someone in your household has consumed any chemicals, don’t take a chance — call the National Poisons Control on 0800 764 766. This is a free 247 service for all New Zealanders.

Medically reviewed in May 2020.

Jan Conway. “Cleaning product sales growth from the coronavirus in the U.S. in March 2020.” Statista. April 17, 2020.
A Chang, AH Schnall, R Law, et al. “Cleaning and Disinfectant Chemical Exposures and Temporal Associations with COVID-19—National Poison Data System, United States, January 1, 2020-March 31, 2020.” Morbidity and Mortality Weekly Report. Centers for Disease Control and Prevention. 2020;69:496-498.
New York State Department of Health. “Interim Guidance for Cleaning and Disinfection for Non-Healthcare Settings Where Individuals Under Movement Restriction for COVID-19 are Staying.”
United States Department of Agriculture Food Safety and Inspection Service. “Cutting Boards and Food Safety.”
Perry Santanachote. “These Common Household Products Can Destroy the Novel Coronavirus.” Consumer Reports. March 28, 2020.
Centers for Disease Control and Prevention. “Cleaning and Disinfecting Your Home.”
Centers for Disease Control and Prevention. “Cleaning and Disinfection for Households.”
M Carder, MJ See, A Money, RM Agius, M van Tongeren. “Occupational and Work-Related Respiratory Disease Attributed to Cleaning Products.” Occupational and Environmental Medicine. 2019 Aug;76(8):530-536.
N Goodyear, N Brouillette, K Tenaglia, R Gore, J Marshall. “The Effectiveness of Three Home Products in Cleaning and Disinfection of Staphylococcus Aureus and Esherichia Coli on Home Environmental Surfaces.” Journal of Applied Microbiology. 2015 Nov;119(5):1245-52.
WA Rutala, SL Barbee, NC Aguiar, MD Sobsey, DJ Weber. “Antimicrobial Activity of Home Disinfectants and Natural Products Against Potential Human Pathogens.” Infection Control & Hospital Epidemiology. 2000 Jan;21(1):33-8.
Utah Department of Health. “Common Cleaning Products Can Be Dangerous When Mixed.”
Elisabeth Anderson, Jinpeng Li. “COVID-19 – Disinfecting with Bleach.” Michigan State University, Center for Research on Ingredient Safety. March 13, 2020.
Environmental Protection Agency-Chemical Safety and Pollution Prevention. “News Release: EPA Provides Critical Information to the American Public About Safe Disinfectant Use.” April 23, 2020.
Ministry of Health New Zealand. (2020). Face mask and hygiene advise. Retrieved from https://www.health.govt.nz/our-work/diseases-and-conditions/covid-19-novel-coronavirus/covid-19-novel-coronavirus-health-advice-general-public/covid-19-face-mask-and-hygiene-adviceStuff. (2020).
Coronavirus how cleaning hightouch surfaces can help to prevent illness. Retrieved from https://www.stuff.co.nz/national/health/coronavirus/120016312/coronavirus-how-cleaning-hightouch-surfaces-can-help-to-prevent-illness
The Spinoff. (2020). How to get rid of covid 19 from surfaces the right way. Retrieved from https://thespinoff.co.nz/science/07-03-2020/how-to-get-rid-of-covid-19-from-surfaces-the-right-way/

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