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Science Says: Wear A Mask
Wearing a mask is a simple thing that you can do to help protect yourself and others from COVID-19. The more things you can do (masking up, social distancing, staying home when possible) the more protection you afford to yourself and those around you, including the people that you love.
This is Part 4 of a series explaining the COVID-19 pandemic. Please consider starting at Part 1: What is a virus or check out the whole series by clicking the button below.
A Brief History of Mask Usage
Today it’s common knowledge that microorganisms such as bacteria and viruses may cause disease in plants and animals (including humans). But a few centuries ago, the causes of infectious diseases and their methods of transmission were not known. Here is a brief summary of how our understanding of disease transmission has evolved and how science proved that something as simple as wearing a mask helps to prevent the spread of disease.
17th Century
Many of the top scientists of the era believed that disease was carried by bad smells or “miasmas”. As a result, their strategy to avoid spreading disease revolved around the avoidance of bad smells.
The first masks appeared during the later waves of the bubonic plague. A French doctor, Charles de Lorme, designed a special suit for physicians treating plague patients. It consisted of a large leather tunic, gloves, boots, a hat, and a mask in the shape of a bird’s beak that contained aromatic herbs.
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Plague Doctor, Rome, Circa 1656 via Wikipedia
Even if the doctors of that time did not know the actual cause of disease transmission, this attire played a part in protecting them from the plague. The leather protected them from disease-carrying fleas, the gloves prevented direct contact with patients, and the herbs in the nose had antiseptic properties, thus neutralizing bacteria passing directly from one individual to another.
19th Century
In the mid-19th century, French chemist and microbiologist Louis Pasteur showed that fermentation and putrefaction are caused by organisms in the air. Later in the 19th century, scientists including Pasteur, Lister, and Koch proposed theories that living organisms called germs were responsible for causing and spreading disease.
“Germ theory, in medicine, the theory that certain diseases are caused by the invasion of the body by microorganisms, organisms too small to be seen except through a microscope.”
-Britannica.com
This theory revolutionized the human understanding of infectious diseases and toppled the miasma theory. In 1870 John Tyndall, an Irish physicist, presented a paper to the Royal Institution in London in which he demonstrated that dust in the air could contain germs and disease and that a cotton-wool respirator could filter them out. Applying his research, he developed a much-improved gas mask for firefighters.
“If a physician wishes to hold back from the lungs of his patient, or from his own, the germs by which contagious disease is said to be propagated, he will employ a cotton wool respirator … Such respirators must, I think, come into general use as defense against contagion.”
-John Tyndall, On Haze And Dust
20th Century
During the early 20th century, various types of cloth masks (made of cotton, gauze, and other fabrics) were used in US hospitals to protect healthcare workers from diphtheria and scarlet fever. Wu Lien-teh, a public-health specialist from Malaya, was investigating a pneumonic plague that had broken out in northern China. He developed a mask from layers of gauze enveloped in cotton, with ties so that it could be hung on the ears. This was the prototype from which the masks currently used in medicine today evolved.
During the 1918 Spanish influenza pandemic, masks made of various layers of cotton were widely used by healthcare workers and the general public. Gauze masks were used during the second Manchurian plague epidemic in 1920–1921 and a pneumonic plague epidemic in Los Angeles in 1924; resulting in a decrease of infection rates among healthcare workers.
During the 1930s and 1940s, gauze and cloth masks were used by healthcare workers to protect themselves from tuberculosis. In the middle of the 20th century, after disposable medical masks had been developed, the use of cloth masks decreased; however, cloth mask use is still widespread in many countries in Asia.
Modern Masks And How they Work
How Can Cloth Masks Prevent the Spread of Disease?
When we breathe, talk, cough, sneeze, or sing, we emit droplets across a range of sizes, and these particles may contain viruses. Putting on a cloth mask can trap these droplets and prevent the virus from spreading to other people.
Cloth is a woven material, with threads intersecting each other in a pattern. It’s true that there are gaps between the threads and that these gaps are larger than the width of a single virus. Sometimes people are lead to believe that the virus is able to simply sail through a mask, but this isn’t true.
.Although the size of a single virus is smaller than the size of the gaps between the individual fabric threads of the mask, the size of the droplets that contain viruses could be bigger than these gaps. In addition, even though there are gaps between the threads in cloth, the individual threads are wider than the gaps. In addition, each thread has microfilaments or imperfections that project into the gap, further providing an obstruction. Finally, a good mask has multiple layers (Health Canada recommends masks with 3 layers) for extra protection.
It’s also worth noting that the droplets containing the virus don’t move in a straight line - they move and swirl in the air which makes them aligning with and passing through a tiny hole very unlikely. And, as droplets are not living things they can’t change direction to go around the fibers or move to avoid obstacles in their path.
Don’t be concerned about an individual gap in the weave of a fabric - instead, think of the entire mask with multiple layers and how everything works together to act as a filter.
Source: Center For Disease Control
Source: The Conversation
What Is An ‘N95’ Mask?
An N95 mask is technically a respirator. In order to use the term N95, the mask (respirator) must be certified by NIOSH - the National Institute for Occupational Safety and Health. During the COVID-19 pandemic we have begun to think of them in association with the medical field, but N95 respirators are used as protection in a number of non-medical fields ranging from autobody repair to construction, welding, and more.
The name N95 is actually a description of the capabilities of the respirator. The ‘N’ means that the respirator is not resistant to oil, and the 95 means that they filter 95% of 0.3 micron and larger materials. There are even multiple types of N95 respirators - including those intended specifically for surgical use and those with or without breathing vent holes.
N95 Respirators utilize capture or filtration to remove airborne particles as described below:
The particles that come in direct contact with the fiber cannot pass through the filter
Larger particles have too much inertia and thus can’t follow the airstream as it is diverted around the filter.
Small particles are easily moved and deviated by air molecules, making it likely that they come into contact with a filter fiber.
For the particles that are neither small enough nor large enough to be captured by any of the methods described above, N95 respirators utilize a type of electrical charge. The charge on the fiber filter attracts the oppositely charged particle, stopping all oppositely charged particles from passing through the filter regardless of their size.
In all cases, once a particle comes in contact with a filter fiber, it is removed from the airstream and strongly held by molecular attractive forces. It is very difficult for such particles to be removed once they are collected.
What’s The Point If Masks Are Not 100% Efficient Or If Other People Don’t Wear Masks?
When it comes to viral science, numbers count. It is true that if everyone in a community wears a mask, the probability of infections drops drastically. The studies clearly show that the more people there are wearing masks, the less the disease will spread.
That is because wearing a mask helps not only the wearer from coming in contact with the virus, but also helps prevent an infected person from spreading the virus. In other words, they offer two-way protection: when breathing in and when breathing out.
Avoiding Misinformation And Memes
There is a lot of incorrect and misleading information available on the internet, and sometimes that information is shared by friends or family members; sometimes even people that we trust.
Just because someone shares incorrect information, that doesn’t mean that they are a bad person - it just means that they’ve made a mistake. Unfortunately, it’s not always easy to tell when a piece of information is wrong. The most convincing, and dangerous, forms of misinformation are those that appeal to our “common sense” or that seem logical when first viewed.
For example, look at this meme often seen on Facebook:
Don’t Be Fooled By Misinformation!
At first look, it appears to make sense: why do I need to wear such a complicated mask when using spray paint, but cloth masks with images of Baby Yoda are enough to protect me from COVID-19?
The answer, also explained above, is simply that while the gaps in a cloth mask may be larger than the size of a single SARS-CoV-2 virus, the virus spreads in liquid droplets. A single layer of cloth might not be great against a single virus, but a multi-layer cloth mask, as recommended by Health Canada, has been proven to be effective against droplets containing the SARS-CoV-2 virus.
Other common pieces of misinformation about masks are that face masks can cause other health problems (not true) or that if you wear a mask you don’t need to practice social distancing (you still do).
Sometimes misinformation comes from a misunderstanding of a scientific article, from old information, or a single report or study that might have errors in it. It’s always a good idea to search for multiple reputable sources of information when trying to confirm a piece of information or advice that you hear.
Wearing a mask is a simple thing that you can do to help protect yourself and others from COVID-19. The more things you can do (masking up, social distancing, staying home when possible) the more protection you afford to yourself and those around you, including the people that you love.
How To Choose The Right Mask
Here are a few things to consider when selecting a mask:
Wear a mask that fits snugly on your face
Put on the mask such that it covers both mouth and nose at all times
Choose a mask with two or more layers of breathable fabric
Use only masks without exhalation valves or vents because they may not prevent you from spreading COVID-19
For more details and the latest updates on mask recommendations, please visit:
World Health Organization: https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public/when-and-how-to-use-masks
Center For Disease Control: https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cloth-face-cover-guidance.html
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Wash Your Hands
Washing your hands is a key part of preventing the spread of all diseases, including COVID-19. Read on to find out why.
Soap doesn’t (usually) kill germs, but it can break them up and remove them. Washing your hands is a key part of preventing the spread of all diseases, including COVID-19. Read on to find out why.
This article is part of a series to help people understand COVID-19. Click the button below to see all of the articles in the series.
Wash Your Hands
One of the most effective ways we have to prevent the spread of viruses such as SARS-CoV-2 is to properly wash our hands with warm water and soap. By doing so, we remove highly contagious pathogens from our skin, preventing those pathogens from spreading to other surfaces we touch or to other people around us. A pathogen is a micro-organism such as a bacteria or a virus that can cause disease or illness in a host.
According to the Government of Canada, we know that the SARS-CoV-2 virus (and accordingly, COVID-19) spreads:
"from an infected person to others through respiratory droplets and aerosols created when an infected person coughs, sneezes, sings, shouts, or talks. The droplets vary in size from large droplets that fall to the ground rapidly (within seconds or minutes) near the infected person to smaller droplets, sometimes called aerosols, which linger in the air under some circumstances.
The relative infectiousness of droplets of different sizes is not clear. Infectious droplets or aerosols may come into direct contact with the mucous membranes of another person's nose, mouth or eyes, or they may be inhaled into their nose, mouth, airways and lungs. The virus may also spread when a person touches another person (i.e., a handshake) or a surface or an object (also referred to as a fomite) that has the virus on it, and then touches their mouth, nose or eyes with unwashed hands.”
It’s All About The Molecules
Proper handwashing is such an effective tool to prevent the spread of SARS-CoV-2 and other harmful viruses because of how soap molecules work.
Scientists know that the structure of the SARS-CoV-2 virus contains a crown of external spike proteins that attach to our cells in order to reproduce and spread throughout our bodies.
“The spike protein is the major surface protein that it uses to bind to a receptor — another protein that acts like a doorway into a human cell. After the spike protein binds to the human cell receptor, the viral membrane fuses with the human cell membrane, allowing the genome of the virus to enter human cells and begin infection.”
These spikes are the reason that we call viruses such as SARS-CoV-2 coronaviruses - under a microscope these spikes resemble the corona of the sun, which looks similar to a crown. The Latin word for crown is corona, hence coronavirus.
Soap molecules are a type of surfactant. These molecules have two opposite ends: one which is hydrophilic (likes water) and one which is hydrophobic (does not like water, but DOES like lipids - natural oils and fats). Many bacteria and viruses are surrounded by a protective lipid layer. These lipid layers protect the virus from threats and also help it to stick to our skin. In addition, our skin is covered in oils and the virus can easily attach to those oils.
When we use soap and water to wash our hands the hydrophilic end of the soap molecules attaches readily to the water molecules, but the hydrophobic ends want to get away from the water. One of the best ways to do that is by inserting themselves into the lipid layer of the pathogens (in this case, SARS-CoV-2) and to the oils on our skin.
As we continue to scrub our hands with soap (for at least 20 seconds) we build a lather and lift these oils from our skin and encourage the hydrophobic ends of the soap molecules to connect with the pathogen. When we rinse our hands, the viruses and oils are washed away.
In the case of SARS-CoV-2 (the virus that causes COVID-19) and other viruses, soap is also very good at breaking up the non-covalent bonds that hold the virus together - breaking the virus apart into tiny pieces.
When we rinse the soap lather from our hands, the viruses (and pieces of the virus) which are now attached to the soap molecules are removed from our skin. Without soap molecules to bind to the proteins surrounding the virus, handwashing would not be an effective means for preventing the spread of bacteria and viruses. This means that simply running your hands under water without using soap is not effective.
You can explore soap molecules at home with this simple demonstration.
How to Wash Your Hands
Wet your hands with clean, running water.
Apply soap
Lather your hands by rubbing them together: rub your palms together, lather the backs of your hands, between your fingers, under your fingernails, your thumbs and up near your wrists. To make sure your hands are clean lather them for at least 20 seconds (an easy way to keep track of the time is to sing Happy Birthday twice)
Rinse well under clean, running water.
Dry your hands with a paper towel and then use that towel to turn off the tap and open the bathroom door if needed. This ensures your hands remain clean without coming into contact with a potentially contaminated surface like a tap or door handle.
Proper Handwashing - Click To Download a PDF
Proper handwashing does more than prevent the spread of COVID-19. According to the Center for Disease Control about 1.8 million children under the age of 5 die each year from diarrheal diseases and pneumonia. It is estimated that handwashing alone could protect 1/3rd of these kids from diarrhea and 1/5th of these kids from pneumonia.
Some Additional Notes That May Be Helpful:
Because the temperature of the water is never hot enough to kill pathogens, even cold water can be used to wash your hands. Some health organizations do state to use warm water, however. This is because warm water may help to maximize the lathering effect of soap.
Drying your hands with a clean towel may improve the benefits of handwashing - the towel can help to remove additional pathogens that may not have rinsed off during the handwashing process.
Running water is a key component to rinse away the germs. Don’t simply use a still tub of water. Remember, handwashing doesn’t kill the germs - it lifts them from your skin and allows you to rinse them away.
Global Handwashing Day is celebrated annually on October 15.
What About Hand Sanitizer?
Hand sanitizer is an alcohol-based chemical compound that has been proven to kill many bacteria and viruses. Hand sanitizer, as long as it contains at least 60% alcohol, is effective in helping prevent the spread of harmful pathogens when access to clean, warm water and soap is not available. One of the key steps in using hand sanitizer is to ensure that it dries on the skin - do not rinse or wipe off hand sanitizer before it is dry or the effectiveness will be compromised.
However, the best option is always to wash your hands with soap and clean running water. Proper handwashing removes all types of germs from your skin, preventing spread and infection, while hand sanitizer works by killing certain germs on the skin. Handwashing can also remove chemicals such as pesticides and certain heavy metals from your skin, and will remove germs that hand sanitizer can not. As a result, alcohol-based hand sanitizers should be used if soap and water are not available, not as an alternative to washing your hands with soap and water.
Additional Sources And Reading
Government of Canada: Coronavirus disease (COVID-19): Prevention and risks
Government of Saskatchewan: COVID-19
World Health Organization: Coronavirus disease (COVID-19) pandemic
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COVID-19 and Mental Health
The total impact of the COVID-19 global pandemic will not be fully known for some time. One thing, however, is clear: no matter your specific experiences during the pandemic, your mental health has been affected.
The impacts — both physically and mentally — of the COVID-19 global pandemic will not be fully known for some time. Whether you’ve had COVID-19 and recovered, were tested and the results were negative, known someone in one of both categories, or you simply have been isolated in your home for months, you have experienced the pandemic and your mental health has been affected.
Today, as we join the conversation for Bell Let’s Talk Day let’s take a look at mental health and mental illness.
What is mental health?
Mental health can be described much like our physical health. We exercise and eat well to maintain healthy bodies. In the case of your mental well-being, you need to give awareness to how you are managing your life, how you cope with the highs and lows, the stresses and anxieties, that we all experience regularly.
Conditions like depression, anxiety disorder, addictive behaviors, and eating disorders are all examples of types of mental illness. They become concerning and in need of attention when your moods, thoughts, and behaviors are impacting your ability to function on a day-to-day basis.
The brain is complex. Let’s look at how it works.
Our brain contains billions of neurons that are essentially the communicators. They communicate with the help of brain chemicals (neurotransmitters) moving from neuron to neuron. You might be familiar with some of the common brain chemicals associated with joy and happiness — serotonin (mood stabilizer), dopamine (reward chemical), endorphins (painkiller), or oxytocin (the love hormone). Working together these brain chemicals all contribute to how we feel emotionally.
Watch this video for a crash course on how brain chemicals work.
Scientific advances in recent years have made it clear that the brain plays a central role in mental health. Our brains are complex organs and much like other organs — the heart, kidneys, or lungs — illness occurs when it is not working properly.
Watch for signs of mental illness
With all the activity happening in the brain it is not surprising that disruptions occur. Like our physical health, learning to recognize the signs and symptoms of mental illness is key. The symptoms can range from loss of motivation and energy, changed sleep patterns, extreme mood swings, disturbances in thought or perception, or overwhelming obsessions or fears. Sometimes symptoms of a mental health disorder appear as physical problems, such as stomach pain, back pain, headaches, or other unexplained aches and pains.
From time to time many of us will experience symptoms and have concerns about our mental well-being, more so now as we live through a pandemic. The good news is there are resources and techniques to help improve your mental wellness. However, sometimes the chemicals in your brain don’t work as they should. For example, if you aren’t producing enough serotonin you may suffer from ongoing symptoms of depression making it difficult, or unbearable to function on a daily basis. Eventually, this affects your life at home, work, or school. Fortunately, there are medications and/or therapeutic ways to help. A visit to your primary health care provider is a great place to start.
What can I do to help improve my mental health?
Start with your outlook on life. Is your glass half full or half empty? Having a positive outlook makes a difference in how you feel. Yes, we all can feel grumpy sometimes, but it has been proven that focusing on the positive, rather than having negative thoughts has an impact on your mental well-being. It won’t happen overnight. It will take work, much like physical exercise, but it is worth the effort.
Here are some simple things you can try today:
• Take a walk or run outside.
• A nap can always give a boost of energy.
• Call a friend or family member.
• Read a book.
• Listen to a podcast.
• Tidy your workspace and get rid of clutter.
Longer term strategies to improve your mental wellness:
• Practice gratitude with a daily journal or create a Gratitude Jar
• Include meditation and yoga in your daily or weekly activities.
• Consider a yearly mental health check-up with a psychologist.
Online Resources:
The Saskatchewan Science Centre is honoured to work with local organizations like The More Joy Movement led by the author of Journey to Joy, Christalee Forese. Learn more about Christalee’s journey and the movement at morejoy.ca
Government of Saskatchewan: Mental Health and COVID-19
Mental Wellness Support Lines in Saskatchewan: CMHA Saskatchewan Division
Depression in men has long been surrounded by strong stigma. HeadsUpGuys aims to destroy these myths and empower men with the tools they need to combat depression.: You’re Not Alone | Depression Stories from Men
Resources for children: CTV Your Morning - 10 Amazing Reads That Will Help Your Kids Understand Mental Health
Did you find this helpful? Consider making a donation to the Saskatchewan Science Centre!
Cleaning, Sanitizing, and Disinfecting
Cleaning, Sanitizing, and Disinfecting… we talk about them all the time, but what do these words really mean, and why should you care?
Cleaning, Sanitizing, and Disinfecting
This article is part of a series of articles designed to provide science-based information to regular people so that they can better understand the science around the COVID-19 pandemic. If this is your first time here, you may want to start at the beginning.
Looking for the answer to a specific question?
Find answers to The Big Questions at the bottom of the page.
We know that the primary way that the SARS-CoV-2 virus (and thus COVID-19 ) is spread is through aerosol droplets. When the pandemic began, and science didn’t truly understand the virus, the disease, or the modes of transmission, precautions were taken to cover all possible modes of transmission, and a lot of focus was placed on surfaces as a vector that was easier to control. Sanitizing wipes became almost impossible to find, and any product in the store that claimed it killed 99.9% of anything flew off the shelves.
People used many terms to describe how to halt the spread: cleaning, sanitizing, disinfecting. Some people viewed these terms as interchangeable, but each has a specific meaning, and there are specific reasons to choose each one. What do the words actually mean? What is the difference between cleaning, sanitizing, and disinfecting?
When a product says it kills 99.99% of germs, what does that mean? Do you need to follow certain precautions for the products to work properly? And do you need to purchase specific products to kill germs and viruses, or do some of the products you already have at home do the job?
A note about ‘killing’ viruses: As we discuss in Part 1: What Is A Virus, viruses are not really alive. So while the term ‘kill’ may be used in reference to viruses, disinfectants really inactivate the virus so they cannot cause harm.
Fomites & Fomite Transmission
There are many different forms of disease transmission. By now, we’re all likely familiar with aerosol transmission – when a pathogen contained in aerosol droplets passes from one animal to another, or Vector-borne, where a disease is spread by an insect (such as malaria or Lyme disease). Fomite Transmission is the name for when a pathogen is transmitted by an inanimate object, or “fomite”. A fomite is any inanimate object, such as a doorknob, light switch, or cell phone, that a pathogen can remain on and be passed from person to person. Fomite transmission can include secondary sources of exposure – for example, when a pathogen is transferred from an elevator button to a finger, and then the finger is used to rub your eye (or pick your nose!).
Imagine a freshly painted wall. Unknowingly, you place your hand on the wall, covering the surface of your hand with paint. You then open a door and leave paint behind on the doorknob. The next person who opens the door also gets paint on their hand and they might place their hand on another wall. Each time the paint moves to a new surface less paint is deposited, but the paint is still present.
Note: The idea of cross-contamination of disease is a common form of Obsessive-Compulsive Disorder called Contamination OCD. While you should make every effort to be safe, such as washing your hands, if the fear of germs or disease is causing stress in your life, consider talking about it with a medical professional.
In order to remove pathogens and other contaminants from surfaces that we interact with every day, there are three commonly discussed methods.
What Is The Difference Between Cleaning, Sanitizing, And Disinfecting?
Cleaning removes dirt, oils, dust, and germs from surfaces. Cleaning generally involves using soap and water and mechanical action (such as scrubbing or high pressure) to remove objects from those surfaces. Cleaning may remove some pathogens, and soap may even kill some pathogens leaving behind fewer pathogens that can cause infection.
Sanitizing is defined by Health Canada as reducing the population of microorganisms on environmental inanimate surfaces and objects. Sanitizing may still leave microorganisms on surfaces. In the United States, the CDC defines sanitizing as “removing the number of bacterial contaminants to safe levels as judged by public health requirements”. Today, many people will think of hand sanitizer when they think of sanitizing, but “surface sanitizers are considered pest control products and must be registered before they can be manufactured, imported, distributed, sold, or used in Canada to ensure they meet Canadian health and environmental standards.“ Surface sanitizers are NOT as effective as disinfectants but may be suitable for your use.
In Canada, disinfectants are treated like drugs and all disinfectants that are approved for sale in Canada will have a drug identification number or DIN. Most disinfectants will likely work against SARS-CoV-2, the virus that causes COVID-19, but Health Canada records disinfectants that have demonstrated that they are effective specifically against SARS-CoV-2 and maintains a list of these hard surface disinfectants on their website.
Disinfectants, household cleaners, and bleach are meant to be used to clean surfaces. Never use these products on the skin or internally (e.g. by swallowing or injecting these products) as this could cause serious harm. – Health Canada
Contact Time or ‘Kill Time’
True disinfectants are not just cleaning products, they are actually tested and controlled by Health Canada as a drug, and are issued a Drug Identification Number. The process of being tested by Health Canada ensures that each product actually does what it claims when the proper instructions are followed. One important part of these instructions is ensuring that the appropriate Contact Time (sometimes referred to as ‘Kill Time’ or ‘Wet Time’) is observed.
Contact Time is the length of time that a surface or object must remain wet with the disinfectant for the disinfectant to work properly and kill all of the germs. Different products have different amounts of Contact Time. This time will be included on the spec sheet for the product along with other information such as pH, and whether or not the product is Food Safe or needs to be rinsed after application.
Contact Time will vary depending on the concentration and strength of the disinfectant being used with stronger and more concentrated chemicals having a shorter Contact time.
Based on this, it might seem to make sense to choose a disinfectant with the highest concentration of active ingredients, but there is a cost. Having a higher concentration and stronger solution may reduce the time needed to disinfect a hard surface, but it also often means that the disinfectant is more likely to leave behind more residue and eventually cause damage to the surfaces which are being cleaned repeatedly.
How Do Disinfectants Work And What Kinds Of Disinfectants Are There?
Disinfectants can be made from many different types of compounds, including Alcohol, Chlorine, Hydrogen Peroxide, Quaternary Ammonium Compounds, and many more. Choosing the proper disinfectant for a specific use case is a subject of much research as the end-user must consider the surfaces to be disinfected, temperature, humidity, ease of use, Contact Time, and whether the disinfectant is food safe.
Different types of disinfectants work in different ways. For example, acidic disinfectants destroy the bonds of nucleic acids and precipitating proteins, while phenols denature proteins and inactivate membrane-bound enzymes.
Food Safe or Food Contact Surface disinfectants are those that can be used in settings where food may come into contact with the surfaces being disinfected, such as restaurants or movie theatres.
How to Properly Disinfect A Hard Surface
Remove Debris. Remove debris from the surface. Imagine trying to spray disinfectant on a surface that was covered in breadcrumbs. The disinfectant may not be able to get under the breadcrumbs, leaving those spaces not disinfected. By removing debris (including dirt, garbage, or food) we ensure that the disinfectant will have full access to the surface to do the work.
Cleaning. Using warm soapy water, wash and dry the surface prior to disinfecting. Washing with soapy water will remove dirt and oils from the surface to allow the disinfectant to have complete access to the surface. Ideally, let the surface air dry or dry with a towel.
Disinfect. Following the instructions on the container, allow the disinfectant to sit on the surface for the specified Contact Time.
Never mix cleaning or disinfecting products. For example, if ammonia and bleach come into contact with each other they create chloramine gas which is toxic to people and animals.
The Big Questions
Does COVID-19 spread on surfaces?
“SARS-CoV-2, the virus that causes COVID-19 may be spread when a person touches another person, or a surface or object that has the virus on it, and then touches their mouth, nose, or eyes with unwashed hands.” - HEALTH CANADA
Can I catch COVID-19 from doorknobs or other surfaces?
“Viable SARS-CoV-2 virus and/or RNA can be found on surfaces for periods ranging from hours to days. Despite consistent evidence as to SARS-CoV-2 contamination of surfaces and the survival of the virus on certain surfaces, there are no specific reports which have directly demonstrated fomite transmission. However, fomite transmission is considered a likely mode of transmission for SARS-CoV-2, given consistent findings about environmental contamination in the vicinity of infected cases and the fact that other coronaviruses and respiratory viruses can transmit this way.” - WORLD HEALTH ORGANIZATION
Do I need to wash my groceries?
“Wash fruits and vegetables under running water. Washing fresh produce with soap, chlorine, or other chemicals is not recommended.” - HEALTH CANADA
“There is no evidence to date of viruses that cause respiratory illnesses being transmitted via food or food packaging.” - WORLD HEALTH ORGANIZATION
What can I use to disinfect my home?
“In non-healthcare settings, sodium hypochlorite (bleach/chlorine) may be used at a recommended concentration of 0.1% or 1,000ppm (1 part of 5% strength household bleach to 49 parts of water). Surfaces must be cleaned with water and soap or a detergent first to remove dirt, followed by disinfection.” - WORLD HEALTH ORGANIZATION
“Prepare a diluted bleach solution according to instructions on the label or if using bleach that has a concentration of 5% hypochlorite, add 5 mL (1 teaspoon) of bleach in 250 mL (a cup) of water, or add 20 mL (4 teaspoons) bleach in 1 litre (4 cups) of water to give a 0.1% sodium hypochlorite solution. Be sure to prepare the solution fresh, when you are intending to use it, and only dilute bleach in water (and not with additional chemicals).” - HEALTH CANADA
Do you need to disinfect? Learn about the difference between cleaning, sanitizing, and disinfecting (above). Many cleaners, sanitizers, and disinfectants are available for home use - read and follow the labels and instructions carefully. Do not mix different types of cleaners.
What are the best ways to prevent me and my loved ones from getting COVID-19?
Follow all Public Health Orders.
Get vaccinated as soon as you are able to.
Stay at least 2 meters away from others who do not live in your household.
Avoid crowds and poorly ventilated spaces.
Clean and disinfect frequently touched surfaces.