Never heard of that method. I preserve my cells in a ~25% glycerol solution. I have an 80% glycerol stock solution and every time I need to make a freezer stock I use 300ul of Glycerol and 700ul of cell culture grown overnight. Then I store the cells at -80C and they could be stored like that for years. In fact, recently I asked my PI for a strain he used to work with and the tube was labeled 1999 and it grew like nothing happened!

Indeed, crypreservation using a cryoprotective agent is the method of choice. Glycerol between 15 and 50% should work well, also Sorbitol was reported in the literature and so you can imagine that other sugar (alcohols) could work as well. Also DMSO is worth a try if you want something different but I wouldn't use an undefined medium like skim milk powder without good reasons. If you don't want to resuscicate your cells but just analyze them, simple vacuum drying is worth a try.

http://onlinelibrary.wiley.com/doi/10.1016/j.femsre.2005.01.005/full

Here's a link to a comparison of deep freezing and vacuum drying.

http://www.jiomics.com/index.php/jio/article/view/115

Thanks

Dear Atheesha, You can please follow the links below to obtain certain valuable informations:-

1. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2551311/

2. https://catalog.hardydiagnostics.com/cp_prod/Content/hugo/CryoSaverSkimMilk.html

Thank you Sandip for referencing our work.   As a victim of Hurricane Katrina in 2005 in New Orleans--where our freezer was off and inaccessible for about a month----10% skim milk works FAR better than glycerol stocks.  We examined numerous Gram negatives and gram positives in a controlled study:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2551311/

 Add 10g Difco Skim milk to water and autoclave for 15 minutes.