Can somebody help me where to find dry long (the slimy one..

My husband is flying to Helsinki for only a few days end of this week and I promised him I will do my best
researching where he can find this, since he has no time to do it himself.
It is one of his childhood memories and he told me so often about this very special kind of joghurtlike stuff.
I would be so happy if I could come up with some information where he could get it.
Since I am doing other diary product myself I know about problems how to keep the culture living while on holiday etc.
I' ve been trying to keep eg Kefir Culture "backups" in the freezer but this did not work out.
This is why a dry starter culture like I know it from different type of yoghurts would be the perfect solution.
Neither do I (we) speak Finnish nor do we live in the USA or UK where you can order it and have it shipped.
SO THIS IS THE CHANCE! I' ve been researching the internet but with no results.
So here in this forum I hope to find some help!!
Thank you in advance, any hint how do go ahead is perfect!
Have a nice day!
Anna