Mold problem in 4°C room

[RayHL]

Hello everyone,

we have a problem with mold and its spores in our 4°C room. It was used as a storage room for several kinds of mold (in unwrapped/unsealed petri dishes) in the last few years while the former department was studying it. Now, this research has been discontinued and we are trying to use it as a "standard" cold room for storage of molecular biology reagents, protein purification purposes and so on. However, you can still smell the mold, and LB agar plates show signs of mold shortly after they have been put there.

Does anybody know how to decontaminate it thoroughly? Or at least an idea how to do it?

Thank you very much in advance!


Greetings,
Ray
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[Dr. Hiranya S. Roychowdhury]

We have used 8-10% bleach successfully on non-porous surfaces.  Stainless
steel benches and tables only should be allowed in a cold rooms.  We have
had to discard any wooden drawers or boxes (and of course those infernal
cardboard boxes) from the cold rooms.

We wiped the surfaces down and left the bleach solution over the weekend.

> Hello everyone,
>
> we have a problem with mold and its spores in our 4°C room. It was used as
> a storage room for several kinds of mold (in unwrapped/unsealed petri
> dishes) in the last few years while the former department was studying it.
> Now, this research has been discontinued and we are trying to use it as a
> "standard" cold room for storage of molecular biology reagents, protein
> purification purposes and so on. However, you can still smell the mold,
> and LB agar plates show signs of mold shortly after they have been put
> there.
>
> Does anybody know how to decontaminate it thoroughly? Or at least an idea
> how to do it?
>
> Thank you very much in advance!
>
>
> Greetings,
> Ray
> --
> Jetzt kostenlos herunterladen: Internet Explorer 8 und Mozilla Firefox 3.5
> -
> sicherer, schneller und einfacher! http://portal.gmx.net/de/go/chbrowser
>
> _______________________________________________
> Methods mailing list
> Methods@...
> http://www.bio.net/biomail/listinfo/methods
>

--
Hiranya S. Roychowdhury, Ph.D.
Asst. Professor,
Health & Public Services
Dona Ana Community College
New Mexico State University
Las Cruces, NM 88003

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[Debra Swanson]

Greetings,

We had this problem a couple years back in our walk-in cold rooms and
the recommendation was to thoroughly clean the room, including walls
and floor, with Dreft detergent.  Also no paper/cardboard storage boxes
are kept at 4° - plastic only.

Good luck with the clean-up!

Deb


On Nov 5, 2009, at 11:25 AM, Thomas Schillinger wrote:

Hello everyone,

we have a problem with mold and its spores in our 4°C room. It was used
as a storage room for several kinds of mold (in unwrapped/unsealed
petri dishes) in the last few years while the former department was
studying it. Now, this research has been discontinued and we are trying
to use it as a "standard" cold room for storage of molecular biology
reagents, protein purification purposes and so on. However, you can
still smell the mold, and LB agar plates show signs of mold shortly
after they have been put there.

Does anybody know how to decontaminate it thoroughly? Or at least an
idea how to do it?

Thank you very much in advance!


Greetings,
Ray
--
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3.5 -
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[Deitiker, Philip R]

Mold grows in cold rooms because moisture collects on surfaces before being picked up by the evaporator coil on the refrigeration system. Many newer cold-rooms have a drying system on them to prevent the build-up of mold. They are expensive.  

In addition people who store live culture in the walk-in coolers have the most problem, because many volatile compounds can be effectively utilized by mold, and particular on wooden and paper surfaces. It is best to keep living culture wrapped or sealed tightly and to keep organic volatiles such as acetic acid, ammonia, amines, sulfides, etc sealed tightly.

One can deal with mold as described below. If the wooden surfaces in the room are wood they have been varnished, the mold and moisture eventually destroys this and a surface such as Stainless steel or polyurethane treated wood may be preferable. Corion or stainless steel works well for table tops.

One very common cause of mold is an improperly working fan-coil unit (the aspect of the machine that transfers air across the evaporator coil). This unit is supposed to pick up moisture and deliver that moisture to its condensate pan, were the condensate is rapidly drained. The condensate pan must be level on the outside edges and drain to a center position and quickly out of the cold-room. It is a frequent occurrence that the fan-coil unit is not doing this properly, the condensate tray builds up water and eventually waves form of the surface. The tops of these waves are picked up by lateral airflow and blow out the front of the unit as aspirate, basically causing all the surfaces in the walk-cooler to become permanently wet. Paper is a most effective collector of this moisture.

-Causes of this can be:
--Microbial clogging of the drain line.
--A unit that is out of balance and vibrating excessively (such as a bad fan-motor bearing)
--With volatile acids -  the corrosion of the evaporator coil or the drain pan itself.
--Other clogging agents.
--Improperly installed or improperly working cooling fans (erratic icing over as another symptom)
--A drain pan that is not properly leveled to expel excess water or blockage of the drain line for any other reason.

Other causes:
--Door left open excessively
--Door seals are no longer separating outside (moist) air from inside (cold) air.

A properly working cooler should not grow mold quickly, I cleaned out a cooler back in 1996 that had papered materials from 1984 stored on its shelf, most items did not have great amounts of mold on them.

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[Mr. Naveen V]

Dear Thomas,



The best, ideal and perfect way to abolish this problem is to fumigate your
4 degree/cold room. There are different ways to fumigate the best way is
KMnO4 (Potassium permanganate) + Formaldehyde (the amount of addition will
depend on size of your room) just i am illustrating the protocol



1. Vacate your room completely (the penetration and disinfection power is so
high it can kill even rigid spores)

2. for room of 10X10 feet you can use minimum of 500g of KMnO4 + 500ml of
Formaldehyde (when both are away they wont react, as soon as you mix it
fumes as volcano you should no be in the room and the surroundings, you
should run away from the room)

3. Seal the room to avoid the fumes to come out of the room

4. Wait for min 12 hours to act completely and efficiently

5. Wet the cloth with ammonia of 500ml and spread in the room for minimum of
6-7 hours to neutralize the fumes

6. Wipe the things with some disinfectant to clean and you can start your
work, I promise you won’t see any single mold for at least next 6 months and
year if you keep clean.



The only disadvantage is when fumigation is going on you can’t sit or work
for one day, maybe you can do this on Saturday night, So that it will be
ready for Monday. This is the usual method we do in CLASS-1 rooms and
CLASS-II, don’t look at the fumes or inhale and don’t near or it will harm
you lot take guidance from your professor and seniors while doing this. Any
thing else please feel free to contact.

--
Yours Sincerely,
*Naveen Vankadari*
Lab No: N209
Graduate Student,
Institute of Molecular & Cell Biology,
ACADEMIA SINICA,
128 Academia Road,section-2,
Nankang, Taipei-115
TAIWAN
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