[Nhcoll-l] Moldy mammal specimens
John E Simmons
simmons.johne at gmail.com
Thu Jul 4 12:23:49 EDT 2024
Joachim,
Thank you for your comments and for posting the two papers.
It seems we are approaching this problem from two different points of view.
Neither one of the papers addresses the specific problem posed by Jessica,
which was what to do about mold on preserved mammal skins. From my point of
view, the issue is not how to kill the mold, but how to safely remove it
while minimizing its spread to other specimens―to do this you must take
into consideration the substrate the mold is growing on, which in this case
is the mammal specimens, some with fur, some without.
The mammal skins with mold growing on them will have already been damaged
to some extent by the mold—what is needed is a method to remove the mold
without causing further damage or spreading the mold to other specimens.
The advice provided by Thacker et al. is good for removing mold from
skeletal specimens which can be submerged in 70% ethanol, but submerging
mammal skins would cause more problems than it would solve. Meier compared
the effectiveness of immersion, spraying, and gas treatments for killing
mold, but as far as I can determine from her article (I do not speak German
so perhaps I have misunderstood the translation), Meier did not attempt to
remove the mold from the paper samples. This is significant because leaving
the supposedly dead mold on the specimens elevates the risk of further
contamination from the inactive mold, and given the difficulty in
distinguishing between an active mold infestation and an inactive one, will
complicate monitoring of the specimens in the future. For these reasons, I
recommend that it be removed from the specimens entirely.
The reason I suggested using full-strength ethanol is because it evaporates
more rapidly from the substrate it is applied to than do weaker dilutions
of alcohol. If applied as I recommended (by rolling a cotton swab moistened
with alcohol over the surface, rather than rubbing the surface), 70%
ethanol is far more likely to penetrate into the skin than 95.6% ethanol.
As Meier points out in her paper, the 70% ethanol was most effective in
killing the mold when the samples of mold were submerged in the fluid, but
much less effective in spray applications, but keep in mind that neither
the spraying or the submersion removed the mold from the paper samples.
I agree with your suggestions for elevating the cabinets from the floor and
keeping them from touching the walls of the storage room—these are both
proven ways to reduce humidity increases from rising damp—and it is
important to determine the source of moisture in the cabinet and why it
suddenly increased enough to enable the growth of the mold.
--John
John E. Simmons
Writer and Museum Consultant
Museologica
*and*
Investigador Asociado, Departamento de Ornitologia
Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Lima
On Thu, Jul 4, 2024 at 12:52 AM Joachim Händel <
Joachim.Haendel at zns.uni-halle.de> wrote:
> No, more is not better here!
>
> 70% ethanol is a fungicide that has a membrane-active effect on the cell
> wall. The 30% water transports the alcohol into the cytoplasm. The
> proteins in the membrane of the mould fungi and spores are denatured and
> the cell is prevented from carrying out vital metabolic processes, which
> kills the fungi and often even the spores.
> In the case of alcohol with a higher concentration, this transport does
> not take place or only to a limited extent. Growth is merely inhibited. The
> spores of the fungi are not destroyed by this application. In addition,
> alcohol in high concentrations can cause shrinkage.
>
> There is an excellent paper on this topic about mould on papers - see
> attachment (sorry, only in German).
>
> I am also enclosing an interesting publication on your topic from the
> journal "Copeia".
>
> Ben wrote that you should check the humidity conditions at the location of
> the cabinet. This is important. It is often sufficient for a better
> microclimate to move the cabinets 1...2 centimetres away from the wall and,
> if possible, place them on feet so that the entire cabinet is ventilated
> and no damp patches form.
>
> Good luck!
> Joachim
>
> --
> Joachim Haendel
>
> Center of Natural Science Collections
> of the Martin Luther University (ZNS)
> - Entomological Collection -
>
> Domplatz 4
> D-06099 Halle (Saale)
> Germany
>
> Phone: +49 345 - 55 26 447
> Email: joachim.haendel at zns.uni-halle.de
>
> >>> John E Simmons <simmons.johne at gmail.com> 04.07.2024, 05:00 >>>
> Ben's advice is good, but you might want to consider using full-strength
> ethanol (95.6%) rather than 70%. At 70%, ethanol is a good biocide, but the
> advantage to full-strenth is that it evaporates faster and therefore is
> less likely to affect the specimen or be absorbed deeply into the specimen.
> I also recommend cleaning the specimens by rolling a cotton swab (Q-tip)
> over the mold rather than brushing.
>
> --John
>
> John E. Simmons
> Writer and Museum Consultant
> Museologica
> *and*
> Investigador Asociado, Departamento de Ornitologia
> Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Lima
>
>
> On Wed, Jul 3, 2024 at 5:42 PM Benjamin Hess <bmhess at umich.edu> wrote:
>
>> Jessica,
>>
>> I treated an entire cabinet with mammal specimens, which included several
>> bats. I am listing our process steps below. If you have any
>> questions, please let me know. I am happy to share more specific details.
>>
>> - Isolate the cabinet out of the collection (if possible). We moved
>> ours to our preparation lab.
>> - Remove moldy specimens from the cabinet and place inside a fume
>> hood.
>> - Discard any archival trays that may hold mold spores. Place in a
>> sealed trash bag.
>> - Use 70% ethanol to wipe all surfaces of the cabinet including seal.
>> If possible, you can spray the cabinet with 70% ethanol. Use HEPA vacuum
>> after each treatment. Repeat 2-3 times depending upon mold severity.
>> - If this is an older cabinet, consider improving the seal.
>> - Check the temperature and humidity conditions of the cabinet
>> location. We discovered an airflow issue and resealed a collection door
>> that contributed to the issue.
>> - Specimens:
>> - Under the fume hood, use 70% ethanol and a small brush like a
>> toothbrush (soft brush or Q-tip for bat membrane) to coat all surfaces of
>> specimens with mold. Use new ethanol frequently based upon mold coverage.
>> - Leave specimens in the fume hood until dry.
>> - With a dry brush, brush specimens toward HEPA vacuum with screen
>> over tip to prevent unwanted vacuuming (e.g., specimen tags).
>> - Depending upon the severity of mold, repeat 2-3 times.
>> - Once complete, dry specimens under fume hood with a drying
>> method for specimen preparation including compressed air and additional
>> drying "dust" for skins.
>> - No paper material beyond specimen labels should be retained.
>>
>> Sincerely,
>>
>> Ben
>>
>> *Benjamin M. Hess | EEB Museums Registrar | **EEB Museums Safety
>> Representative to the RMC *
>>
>> University of Michigan | LSA Ecology & Evolutionary Biology | Research
>> Museums Center
>>
>> 3600 Varsity Drive, Ann Arbor MI 48108-2228
>>
>> bmhess at umich.edu | 734-764-2432
>>
>>
>>
>>
>> On Wed, Jul 3, 2024 at 2:56 PM Jessica E. Light <
>> jessica.light at ag.tamu.edu> wrote:
>>
>>> Hi everyone,
>>>
>>> Anyone have any advice for the best treatment for mold on preserved
>>> skins (small mammals, primarily bats, mostly on exposed wing and tail
>>> membranes and ear/face tissue) and skeletal elements (mainly skulls)? I'm
>>> looking for advice for treating the specimens themselves as well as the
>>> cases in which the specimens are stored.
>>>
>>> Thank you in advance for your help!
>>> Jessica
>>>
>>> --
>>> Dr. Jessica E. Light (she/her/hers)
>>> Professor and Curator of Mammals
>>> Department of Ecology and Conservation Biology
>>> Biodiversity Research and Teaching Collections
>>> Texas A&M University, College Station, TX 77843https://lightjessica.weebly.com
>>>
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