-80 Storage - What temp fluctuations are okay? (Jan/24/2010 )
Need some quick advice:
The door to our -80 freezer was left open for too long by members of another lab and the temperature raised to around -60. I don't have anything stored in there right now, but it's jam packed with stuff from other members of my lab. I am just wondering what kinds of things could have possibly gone bad or lost viability with a temperature change like this? It took almost an hour for the temperature to go back down, could we have lost some of our bacterial strains stored in there?
Iwas always told that -80 is much colder than it needs to be for most biologicals. I think your bacteria will be fine, as should your RNA, proteins, etc. Most of the mass of the freezer will still have stayed below -60 unless every rack was taken out and warmed a bit.
-60oC is about the temperature you would get on shipment of cells with dry ice which is quite a common practice.
bob1 on Jan 24 2010, 04:13 PM said:
The people from another lab were looking through many of the shelves trying to find something, so ... I guess I thought it might count as a freeze/thaw cycle. Not that any samples would have thawed completely, but the water activity of the samples would have increased possibly reducing the number of viable cells or allowing for slight protein degredation?
Thanks for your input!
First if the temperature is measured in the freezer it doesn't mean that your samples also are raised to -60. We have a temperature monitor system that has a alarm set to -65 because we think, after literature research, that at this temperature the samples still will be preserved.
You have to realize that even at -80 some protein will degrade. (Even some proteins degrade because of the low temperature.)
There is very little know about individual protein stability and sometimes you see conflicting results in papers.