Is there evidence that samples are safe at -70C?
Spoiler alert - YES! If you've been following My Green Lab, you know that we coined the phrase '-70 is the new -80'. Adjusting your ultra low temperature freezer set point to -70C can reduce energy consumption by 30-40% and prolong the lifetime of a compressor-based freezer. For years we've been directing people to check out the incredible crowd-sourced document, that Dr. Kathy Ramirez-Aguilar at CU Boulder put together, of samples that have been stored at -70C. And now, thanks to our collaboration with the European organization EGNATON on the Freezer Challenge, we have been made aware of these two publications, which show sample stability at -70C for yeasts and molds, and the enzyme PON1. Furthermore, suppliers such as GE and Qiagen have updated their storage recommendations to -70C for certain reagents as well.
The community is still working on obtaining evidence for a wide range of samples, but it's clear the evidence is mounting in favor of safe, sustainable sample storage at -70C.
If you choose to set your ULT freezer to -70C as part of the Freezer Challenge be sure to add your name and your samples to the Google doc! We would also be happy to add them for you - just email us at email@example.com.
Spring is officially here (in the Northern hemisphere) and that means it's time to do some spring cleaning. That's right - it's time to put on some gloves and dig through your refrigerators, freezers, and cold rooms to find those long-forgotten samples.
Thankfully there is a reward for your hard work - Freezer Challenge points! Whether you're cleaning out your cold storage units for the first time ... ever, or whether you have just cleaned them out, the Freezer Challenge gives generous points to any lab willing to re-evaluate the samples they store in their freezers and refrigerators.
Cleaning out cold storage units has three main benefits: