The insect killing protocol you describe is for freezers which are
unable to reach and sustain the recommended temperature for killing all
the life stages of the insect for a full week.  The target temperature
for killing all stages of insect life is at least -20, and the typical
chest freezer you might use in your home doesn't stay at the necessary
temperature continuously if it is a "frost free" model.  In order to
stay frost free, the freezer warms up on a cycle to prevent frost build
up.  This warming allows some insects to form a kind of anti-freeze
chemical in their bodies and survive the cold.  If you remove them from
the freezer and allow them to return to room temperature for a day or
two, this antifreeze mechanism can then be foiled by re-freezing for
another week.  Two standard resources for the process can be found on
the internet:

National Parks Service Conserve O Gram number 3/6 from July 1994
http://www.nps.gov/history/museum/publications/conserveogram/03-06.pdf

Canadian Conservation Institute Notes 3/3 from 1997
http://www.cci-icc.gc.ca/publications/ccinotes/pdf-documents/n3-3_e.pdf


Good luck!
Ellen Carrlee

Conservator
Alaska State Museum
395 Whittier Street
Juneau, AK 99801
(907) 465-2396 
-----Original Message-----
From: Museum discussion list [mailto:[log in to unmask]] On
Behalf Of George Harris
Sent: Tuesday, July 10, 2007 12:14 PM
To: [log in to unmask]
Subject: [MUSEUM-L] Drestmid killing schedule

Hi,
We have some objects that are being treated for drestmid infestations. 
They have been in a freezor for over two weeks.  The previous
collections
manager said that they should now be taken out for two weeks to allow
any
existing eggs to hatch (because they are not affected by the cold) and
then the objects put back in the freezor for two weeks to kill newly
hatched bugs.  Then if we felt it was necessary repeat the process
again. 
The current collections manager said that where she worked before they
only froze objects for one week and that was it and that was supposed to
kill all the bugs and any eggs.  What is the correct way for doing this?

Thank you.

Beau Harris
Registrar
Fairbanks Museum and Planetarium
1302 Main Street
St. Johnsbury, VT 05819

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