I’ve just been through the only other sous vide for face masks thread, read everything, watched all the videos, etc., but that information only seems to deal only with N95 masks. But most of us who are not healthcare workers are wearing cotton masks (or some other fabric material).
My partner and I go out infrequently, and I’m trying to come up with a good way to sanitize our masks as soon as we walk in the door so we can get in the habit of doing it. I figure, with SV, we could start the water bath before we leave, then it would be ready when we return. I’ve looked at the rice cooker and instant pot approaches and want to compare those with sous vide.
Can anyone who really knows about this topic post temperature/time and method for SVing a fabric face mask? If sealed inside a ziplock bag with as much air pressed out as possible, would SV work? Or should they go directly into the water, then be hung up to dry? Should the disposable filter that so many masks come with now be removed, or could it be sanitized as well along with the mask?
Diane, welcome to your Community here, and congratulations on being a diligent mask user.
I wouldn’t reprocess masks the way you want to. It’s likely heresy to post this here, but i use a different technique because i only want to wear a clean and disinfected mask. Sanitizers typically kill fewer germs and just plain water and heat won’t do the whole job either. And the last thing you want to do is incubate and grow any virus cells that might be present on your masks.
Most disposable mask filter inserts are not meant to be reprocessed. Have you tried using half a paper drip coffee filter as a disposable replacement liner?
I vigorously disinfect several masks at a time in a solution of laundry detergent, 10% bleach, and hot water ( >160F), rinse well, and hang to dry in sunlight if possible. It takes about a minute per batch after heating (sans SV) the water to complete the task. Use tongs as the water has to be too hot to touch.
Why do it this way?
The bleach and hot water kills the virus while the detergent weakens the waxy outer layer of the virus and removes any soil and dead cells from the mask material which you won’t want to inhale.
Ample rinsing and sunlight is advised to rid the masks of any beach odour.
Good advice, chatnoir. I haven’t tried the coffee filters, but those would be a heck of a lot cheaper than the filter inserts!
I suppose since we go out so infrequently (we broke down and signed up for a year of Instacart Express for groceries), doing it the way you suggest would not be such a big deal. We have a very shady lot, though, so I’m thinking it would be better to dry the masks in the dryer. Of course, we could wash them in the washing machine, too, I suppose. Something I was reading today said that’s what the experts are recommending people do, washed on warm or hot.
It’s good to know you found the information helpful. Your reply is appreciated.
If you use a dryer consider setting it on “delicate” so your masks’ elastic straps aren’t ruined. Since you don’t often go out you might just dry them at ambient temperature indoors. They will dry overnight.
Of course you can simply launder your masks. There’s not to much risk from your masks if you enjoy normal good health.
However, at my advanced age i am more comfortable using a higher temperature than most people set their water heater at in order to achieve the virus’s thermal death point. Please know 160F hot water can be dangerous, particularly if there are children who may come in contact with it. ( I’ve seen far too many accidentally scalded children.) It also wastes a lot of energy unless you have a tankless system.
I really do think, the more I think about it, that I might plan on using my Instant Pot under pressure. I know it’ll get hot enough that way.
Thanks for sharing the interesting outcome of all your thinking. It will be plenty hot.
If you have masks with tie straps instead of elastic straps your IP with just water certainly won’t do any harm, - and if appearance doesn’t particularly matter as it may not leave your masks looking clean
FYI - you can’t incubate viruses on a mask. Viruses require live cells as hosts to replicate, they can’t replicate on their own the way bacteria can. Heat alone will kill the viruses, but I am not qualified to provide specific guidance on temp and time, though I don’t see why it would be any different for N95 vs fabric or surgical masks.
There appears to be lots of live cells and moisture on my masks after wearing them for a few hours, particularly in the current heat wave. It’s good to know viruses can’t replicate on masks.
There’s considerable scientific evidence that using FDA approved ambient temperature sterilizers with combinations of ozone and hydrogen peroxide have been demonstrated to be effective in healthcare facilities.
JoshK, I agree with you. There is no reason disinfecting an N95 mask should be different from a cloth mask. There are special instructions for the N95 due to the valve, but with a cloth mask you don’t have to worry about the valve. (Besides, the general public is being cautioned against wearing any kind of mask with a valve because, although it may protect you, it does nothing to protect those around you if you are infected - whether asymptomatic or not.)
I subscribe to consumerlab.org . It is an incredibly helpful resource. Takes no advertisements and runs thorough tests on anything they review - primarily supplements - for inappropriate content, etc. Since the pandemic, they have been supplying extra information about anything related - pulled mainly from authoritative studies.
FWIW, they cited recent tests in Hong Kong demonstrating that the Sars-CoV-2 virus (in a culture medium)
became undetectable after 5 minutes at 158 degrees, 30 minutes at 132 degrees, two days at 98.6, two weeks at 71.6 . Remember that this was tested in a culture medium which would tend to make the virus hang around longer. (Chin, Lancet 2020) As for sterilizing in a sous vide, they cited from another study for N95 masks (again, should be no different), that 30 minutes at 149F should do the trick. With the N95 mask it should be elevated over the water on a rack, and the mask or masks can be placed inside a paper bag and stapled.
Steam sterilization has indeed been validated for this use. Don’t recall the time, but I’d do 212F, 100% steam, for the recommended time (I think it’s 5 minutes, but don’t quote me.)