[Nhcoll-l] Moldy mammal specimens
a.j.van_dam at lumc.nl
a.j.van_dam at lumc.nl
Fri Jul 5 07:47:02 EDT 2024
Dear All,
If it is important to kill the active mould together with the still inactive spores, there are 2 methods that work very well, although both need some safety measures to be applied and might affect DNA.
1.
Short exposure to gamma-radiation (commercially applied in the food industry)
2.
Expose to formaldehyde vapor (8% formaldehyde dissolved in water; in US mostly known as 20% formalin)
Of course, there is the question if it is necessary to kill ALL the spores or just remove most of them for instance by using vacuum cleaner with HEPA filter. Mold spores are always present in the air and having a spores-free environment will be an illusion.
If mold is difficult to remove, wet cleaning might be considered. The antimicrobial spectrum of ethanol is the widest around 70%. The risk of severe dehydration of the skin is much higher when exposed for prolonged times to ethanol concentrations above 80%.
Kind regards,
Dries
Andries J. van Dam<https://www.linkedin.com/profile/preview?vpa=pub&locale=en_US> | curator-conservator
Anatomical Museum<https://www.lumc.nl/onderwijs/over-ons/anatomisch-museum/?setlanguage=English&setcountry=en> | Directorate of education | Leiden University Medical Center | Building 3 (V3-32)
P.O.Box 9600 | 2300 RC Leiden | Netherlands
Visiting address: Hippocratespad 21 | Tel: +31 (0)71 52 68356 | E-mail: A.J.van_Dam at lumc.nl<mailto:A.J.van_Dam at lumc.nl>
Scientific associate | Natural History Museum London
________________________________
Van: Nhcoll-l <nhcoll-l-bounces at mailman.yale.edu> namens John E Simmons <simmons.johne at gmail.com>
Verzonden: donderdag 4 juli 2024 18:23
Aan: Joachim Händel <Joachim.Haendel at zns.uni-halle.de>
CC: jessica.light at ag.tamu.edu <jessica.light at ag.tamu.edu>; nhcoll-l at mailman.yale.edu <nhcoll-l at mailman.yale.edu>
Onderwerp: Re: [Nhcoll-l] Moldy mammal specimens
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<mailto: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<tel:+49%20345%20-%2055%2026%20447>
Email: joachim.haendel at zns.uni-halle.de<mailto:joachim.haendel at zns.uni-halle.de>
>>> John E Simmons <simmons.johne at gmail.com<mailto: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<mailto: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<mailto:bmhess at umich.edu> | 734-764-2432<tel:734-764-2432>
On Wed, Jul 3, 2024 at 2:56 PM Jessica E. Light <jessica.light at ag.tamu.edu<mailto: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 77843
https://lightjessica.weebly.com<https://lightjessica.weebly.com/>
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