Quick question: how long will mold cultures (geo & p. candidum) last reconstituted in water, stored in a spray bottle in the refrigerator? I have some that have been in there for a couple of weeks now and would rather use them than mix up a new batch. Thoughts?
Pure spores? In sterile water? 5-20 years.
Normal water/impure spores (spores with media or substrate)? maybe 6-12 months?
Anything else depends on how you did it. Do you mean they're mixed together?
I have a spray bottle with distilled water, a pinch of salt, a pinch of sugar, and a small amount of Choozit Geo 13 and P. Candidum. I sprayed some cheeses a few weeks ago and put the remainder in the refrigerator. I just wasn't sure if it would still be effective, or if I should mix up a new batch using new freeze-dried cultures.
You're fine. After it becomes turbid, you have about 2 weeks before you need to rebatch that mix. if you did it in sterile water, it would last years.
Where do you get sterile water?
I make mine. For a quick solution, take RO or distilled water, and boil it, or if possible, boil in pressure canner. Cool and use. Or filter through a bacteriological filter. Or autoclave.
Thank you.
arkc
Some spores can survive boiling, right? So using distilled water solves this problem? My water supply is a cistern. I usually boil water before using to dilute rennet etc, but always wonder if something might survive.
Susan
QuoteSome spores can survive boiling, right?
Many can, yes. That's why one autoclaves, 121C for 15-20 mins.
QuoteSo using distilled water solves this problem?
mmm, if one has a good process, most of the time, yes.
QuoteI usually boil water before using to dilute rennet etc, but always wonder if something might survive.
Yes, but honestly, there's more risk of contamination from the environment/during handling than spores surviving. It's typically a non-issue in practical use.
Good to know. Though I DO have access to an autoclave. Maybe I'll sterilize a half-gallon or so...
Susan