Innoculated Refirgerated Agar Slant shelf life

Sawdustguy · 09-02-2009, 07:48 AM

Once I innoculate an Agar slant with a colony of yeast and put it in the refrigerator how long can I expect it to be useable?

JKoravos · 09-02-2009, 01:16 PM

I've seen anywhere from 3 months to >1 yr. I think conventional wisdom is 4-6 months, but in reality most will last a year or more.

Anyone else feel free to chime in and disprove me. I'm new to slanting, I did my first slants in May and started my first starter off a slant last week.

**pjj2ba** · 09-02-2009, 02:00 PM

Properly stored in a fridge, I've had year old plates I've recultured from. Of course the yeast may have changed a little over that time. Frozen stocks is best of course

PseudoChef · 09-02-2009, 02:08 PM

It depends on how air-tight they are. I have found that wrapping parafilm around the caps helps to increase shelf life.

Sawdustguy · 09-02-2009, 02:10 PM

I didn't know I could freeze them. Is that true? I have a large chest freezer that has plenty of space for storage. Are there any caveats to freezing them?

PseudoChef · 09-02-2009, 02:51 PM

You will need to suspend the cells + medium in approximately 15% glycerol and keep in a freezer that does not have a freeze-thaw cycle.

fratermus · 09-03-2009, 02:24 PM

Quote:

Originally Posted by Sawdustguy

Once I innoculate an Agar slant with a colony of yeast and put it in the refrigerator how long can I expect it to be useable?

The general idea is to reculture every few months.

I had a series of 3068 batches start doing weird "no floc at all" behaviour after just under a year at 40F. Others have reported no obvious problems.

Storage in frozen media or room-temp distilled water (see sig) are recommended if you don't want to do the "serial reculturing" thing.