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katbusa
TC Enthusiast

Registered: 02/19/13
Posts: 172
Last seen: 6 years, 8 months
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LFH why no hoods?
#17833235 - 02/19/13 10:23 PM (11 years, 2 months ago) |
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First time post and hopefully more. I hope I'am putting this into the correct forum. If I'm not please go easy and point me in the correct direction.
I have been viewing this forum for some time and I have noticed people are using Laminar Flow Hoods with out the hoods that help keep dust off the working surfaces. I do not know much about mycology. I do know a good bit about plant tissue culture. I own a 24x36 LFH that I use for plant TC. I have read about people having contamination issues while still working under a LFH. The first thing that pops to my attention is that some people have no way to keep dust from landing on their cultures. Dust alone can carry some nasty microbes. With out the hood dust is still a major factor. The only thing that I can imagine why no hood is used is because of the size of the fruiting chambers.
Maybe I'm missing something. I'm not totally sure and I'am a complete noob when it comes to fungi. I just know the sterilization protocols I go through with tissue culture have to be to the "T" or plants will not strike or your get some nasty contamination that consumes the explant.
Please enlighten me for I would like to learn.
Edited by katbusa (02/19/13 10:35 PM)
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Fruitbuddy
Mycophilic Cultivator


Registered: 09/01/10
Posts: 214
Last seen: 7 years, 6 months
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Re: LFH why no hoods? [Re: katbusa]
#17834248 - 02/20/13 05:23 AM (11 years, 2 months ago) |
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my flowhood has a hood. the hood does not only protect the filter, but also from turbulences, and it helps the laminar flow "finding its way", if you will. it does work without a hood, but gives a higher risk, especially the nearer you get to the edges of the filter.
small dust particles should not be heavy enough to overcome the laminar flow. this depends on flow speed and particle size/weight.
the reason for many not to build a hood, is probably indeed space requirements. you are speaking of fruiting chambers here, but flowhoods have nothing to do with fruiting chambers.
when there are contamination problems in a flowhood, may it be DIY or professional, it's usually because of poor technique, broken filters/insufficient sealing or spore-infested hoods/filters. if the sealing is sufficient, but there is a source of contamination, uv-c radiation can help to sterilize the hood, like used in many professional enclosed hoods for surface sterilization with protective measures against the radiation.
i don't routinely use uv-c irradiation, but i did use it to initially sanitize the work area of my flow hood after building it.
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Amanita virosa
botanist by day



Registered: 12/04/11
Posts: 2,458
Loc: north kakalacky
Last seen: 10 months, 4 days
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Enclosures limit space and are less convenient to use. They can get in the way to a certain extent. They can also make it difficult to get right close to the filter. I work literally two inches from my filter most of the time. With an enclosure I would have to have my whole body inside to get that close Dust particles are swept away from the workspace by laminar flow. I run test plates once a week while working. I can leave an open plate in front of my lfh for six hours or more with zero contam. Folks having contam issues either have a faulty filter or are not practicing sterile technique.
Edited by Amanita virosa (02/21/13 10:19 AM)
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RogerRabbit
Bans for Pleasure



Registered: 03/26/03
Posts: 42,214
Loc: Seattle
Last seen: 1 year, 2 months
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Exactly. It's a space thing. Also, dust doesn't settle into the laminar flow. It's pushed back and away. There's also no turbulence because we work in small, closed rooms in which we run the flow hood for at least an hour before use to pre-scrub the air of contaminants. We wipe table surfaces with disinfectant before use. RR
-------------------- Download Let's Grow Mushrooms semper in excretia sumus solim profundum variat "I've never had a failed experiment. I've only discovered 10,000 methods which do not work." Thomas Edison
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t3chnobily
Strangest


Registered: 02/04/12
Posts: 651
Loc: As Seen In VT
Last seen: 7 years, 1 month
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I built mine with a small "hood" because I had the space and material.

Glass top lets me get close to open dishes for inspection/photography. Also a sneeze guard. Pretty happy with it so far. Still need to enclose the lab like RR said but too busy with work. Soon....
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katbusa
TC Enthusiast


Registered: 02/19/13
Posts: 172
Last seen: 6 years, 8 months
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RR I totally understand and I see where it makes sense not to use an enclosure. The thing is the hood causes the air to be funneled in one direction which in turn can increase the workable are. I'm not saying not using an enclosure does not work. I'm used to having to run my LFH for a good amount of time while replating 75-100 culture. Not useing an enclosure is somewhat new to me. I think it will be something to try on my first myco grow.
Thanks guys! I think you might have opened the door to a different method of use for my LFH. It might work for tissue culture. Ill give it a shot and see what happens.
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