White Coat, Black Art

The Dose: What you need to know about face masks and food safety

Dr. Goldman talks to 'the germ guy', Jason Tetro. They cover: How to don and doff a mask. The best material for making masks. Should a mask cover your nose? Can hospitals clean masks?  Should you worry about take-out food? Should you share homemade food? Does heat kill the virus on food? Do you need to disinfect every item from the store? Is it safe to handle money? What about pin pads?  Do gloves protect you from anything? 
Microbiolgist Jason Tetro offers tips on faces masks and food safety during COVID-19. (supplied by Jason Tetro )
Listen to the full episode19:21

In this bonus episode of The Dose, we talk microbiologist Jason Tetro, 'the germ guy," The author and host of the 'Super Awesome Science Show' podcast. separates fact from fiction about masks and food safety, in relation to COVID-19. 

Making a mask at home? Go for layers

When it comes to homemade masks, Jason Tetro, aka "the germ guy", says to imagine the layers of material that envelop you when you sleep.

"I like to idealize your bed when it comes to masks," Tetro told Dr. Brian Goldman, host of the CBC health podcast The Dose

"Cloth masks, the homemade stuff that we have at home, [they're] kind of like sheets."

Surgical masks, on the other hand, are made with a nonwoven material, more similar to a pillow, Tetro said.

For daily use, he recommends multiple layers of material that may protect up to 60 per cent of the droplets that could be in the air nearby. 

"Remember when we're talking about droplets, for the most part, unless you're taking a picture of someone sneezing with a backlight, you can't really see them," Tetro said. 

"So, you have to be aware that yes, indeed, [the droplets] are going to be small enough to get through that first layer. But if you've got the second or the third or the fourth, you're reducing the probability of it getting through and as a result of that you're improving the chances that you're going to be safe."


Wearing a mask during intimate encounters with new partners is a best practice during the pandemic, according to experts. (Fabiola Carletti/CBC )

Not sure what fabric to use? Go dense

For the most effective coverage, go with wool material that has a high density, and if that's not available most fabrics you find around the house will do.

"The fact is that we can use almost anything. So, if you look at some of the studies that have been done, you'll actually notice that pillowcases can be used, T-Shirts can be used, dish towels can be used," the microbioligst said. 

And if no scarves or shirts are on hand, mask makers need not feel limited to traditional types of cloth.

"Believe it or not, they've actually shown that a vacuum cleaner bag is almost as effective as a surgical mask, If you want to go for it. Hey, why not? But I probably would suggest that you leave that for your vacuum," Tetro said. 

Not sure how to wear your mask? For starters, never touch your face

The question of efficacy of homemade masks is getting a lot of attention on the world stage, as public health officials tell citizens that non-medical masks are a practical way to protect yourself and those around youif used correctly.

Tetro said there is danger related to improper handling of a mask, adding it's not just about refraining from touching your mouth and nose when putting on the mask, it's about avoiding adjusting or touching the mask once it is on. 

"When you're wearing [a mask], you have to maintain that constant pressure and constant coverage. If your face starts to itch, you can't scratch it. If you suddenly have to say something or something feels muffled, you can't take the mask off," Tetro told Goldman.

"You can't touch that front part of the mask because that risks any kind of contamination onto your fingertips."

You should not touch the outside of the mask when taking it off, and properly dispose of it, or store it for sterilization before reuse. 

"You have to essentially take it off from the back so the straps come first, and then it comes down. The part that has been potentially contaminated stays away from you until it goes either into the receptacle or into whatever package it's going to be, if it's going to be reused."

Worried about COVID-19 on groceries? Rinse or leave for a few days

With the importance of handwashing and social distancing well established, many still wonder what's the best way to clean food.

Tetro said the key ingredient comes down to heat and when the food will be used.

The grocery store is one of the few places left where we can have interactions with people. Experts say it's important to keep being friendly where we can during the pandemic. (wavebreakmedia/Shutterstock )

"What I like to say is that 65 degrees Celsius and above is really all that you need."

"Any kind of cooking that you're doing, and heck, even reheating in a microwave, if it's hot to taste, if it's hot to touch, then you've probably done an effective job of getting rid of this virus."

As for instructional videos posted online of people disinfecting each item that they get from the store, Tetro thinks the message goes too far.

"The only things that you really need to be thinking about [for cleaning] are produce because most of the time you're having that within that 48 to 72 hour period where the virus may still be alive." 

His advice: run food under water, and rub gently with "a little bit of friction, nothing huge, as if you were sort of rubbing raspberries."

Tetro says the coronavirus droplets are not part of the integral makeup of the food but on the outside layer and very easy to take off. 

As for your cans, as long as they won't be used immediately, they can go right into a dark cupboard or pantry for 48 to 72 hours or longer to get rid of the virus. 

For plastic, Tetro says you can wipe it down with soap and water if you really want to, "but again, unless you're going to be using it within that two to three-day period, why would you even bother? Just make sure that after you've handled your groceries, you're washing your hands just to be sure."

Craving take-out? Order in, just don't lick the containers

What if you're craving a slice from your local pizzeria or some sushi? There are precautions you can take if you miss eating at local restaurants (and want to support them by picking up dinner).

As for the menu, Tetro says most of the risk comes with foods that aren't heated (like salad) because cooking food will kill the virus. However, he does caution against licking the containers.

"Cardboard is porous, [and] it's actually going to absorb the virus," Tetro told Goldman, explaining that studies have shown a deep scrub is necessary to get the virus out of cardboard because of how it soaks in to the material.

Signs relating to the coronavirus outbreak are displayed on the doors of businesses in Carleton Place, Ont., on Friday, March 20, 2020. As many business have shuttered their doors due to the COVID-19 pandemic other business have continued with take-out and delivery. (Sean Kilpatrick/Canadian Press)

Tetro said just use common sense about getting your meal into your home and to your dinner table.

"It's being trapped when it's traveling [from the restaurant to your home], it's probably inside a secondary container that is held by the delivery person. The only opportunity that you could possibly have any kind of contamination is when that particular driver is taking the food out of that secondary container and handing it to you."

Tetro advises taking the container out of the bag in the entrance way of your home and leaving it there (to dispose of later), and then washing your hands before taking your food itself out to eat.

Baking for a neighbour?  Think twice

As for making food to share with neighbours, Tetro does not encourage it.

"When we're talking about a homemade pie, we're starting to get a little bit into that sort of iffy zone," Tetro told Goldman.

"[Although] the pie has been cooked... I personally would still say that it's best for you not to do this."

If you're going to share food, best that you cook it and transport it in a container that can be wiped down with soapy water, and when you're dropping it off, don't come within six feet of anyone you're not living with.

Do you have questions for The Dose? Let us know what they are and we'll do our best to get you the answers you're looking for. If there's something you want us to tackle — let us by emailing TheDose@cbc.ca or tweet us @cbcwhitecoat or @nightshiftMD with the hashtag #TheDoseCBC.  

Produced and written by Arianne Robinson. 




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