Hi Angela, Please refer to the following passage in the linked document on freezing:
"The two major insect adaptations to cold are to avoid freezing or to tolerate freezing. Insects that avoid freezing do so by increasing the concentration of glycerol and sugars in their tissues in order to lower their freezing point. Sufficient time for metabolic changes (acclimation) and habitat preparation is necessary for these insects to survive such low temperatures. Low temperature extermination methods usually eliminate this period of adaptation. Insects that tolerate freezing do so by controlling ice formation in their bodies by infusing a special nucleating protein into their body fluid. These insects can remain frozen for months and still recover on thawing. Insects generally do not maintain these cold protective systems when their environment remains relatively warm (late spring to early autumn conditions) because there is a metabolic cost involved. For this reason, determine the past temperature history of the artifact and allow a preconditioning quarantine period in warm temperatures if the object has come from cool or cold conditions. As a rough guide, allow one month at room temperature to induce insects to flush protective substances from their bodies." Controlling Insect Pests with Low Temperature – Canadian Conservation Institute (CCI) Notes 3/3 - Canada.ca<https://www.canada.ca/en/conservation-institute/services/conservation-preservation-publications/canadian-conservation-institute-notes/controlling-insects-low-temperature.html> Perhaps more people can weigh in on their experiences dealing with this specific situation, however the linked document above suggests that you should let the objects warm up again for a month and then re-freeze if they have not been frozen for at least a week at -20C. Best, Cynthia Cynthia Kapteyn Book and Paper Conservator, Digitization Coordinator The Huntington T: 626-544-0338 | E: [email protected] 1151 Oxford Rd, San Marino, CA 91108 [The Huntington Logo.png]<https://www.huntington.org/> ________________________________ From: [email protected] <[email protected]> on behalf of Duckwall, Angela, DCA <[email protected]> Sent: Friday, August 8, 2025 10:31 To: [email protected] <[email protected]> Subject: [PestList] Freezer query You don't often get email from [email protected]. Learn why this is important<https://aka.ms/LearnAboutSenderIdentification> This query is sent on another institutions behalf and they were in the middle of low temperature treatment for a clothes moth infestation: We have the freezer truck, and its been holding at -4F for since Monday, but then we had an issue with the truck and it shut off at 2am and the temp went up and it took like 12 hours to get back down to -4. It is back up and running correctly, and cold again, but my question is: does this re-set the clock for my 2 weeks at -4? Do I need to have 2 weeks of continuous -4? Or is a freeze, short thaw, freeze within the 2 weeks sufficient do you think? Just trying to figure out if I need to extend the rental for the freezer. Thank you, Angela -- You received this message because you are subscribed to the Google Groups "MuseumPests" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]<mailto:[email protected]>. To view this discussion visit https://groups.google.com/d/msgid/pestlist/SJ0PR09MB9953620612BAE65FA443A20FC02FA%40SJ0PR09MB9953.namprd09.prod.outlook.com<https://groups.google.com/d/msgid/pestlist/SJ0PR09MB9953620612BAE65FA443A20FC02FA%40SJ0PR09MB9953.namprd09.prod.outlook.com?utm_medium=email&utm_source=footer>. -- You received this message because you are subscribed to the Google Groups "MuseumPests" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/pestlist/SJ0PR10MB4575DB0294828D4C8D225E47A32FA%40SJ0PR10MB4575.namprd10.prod.outlook.com.
