Frozen dried culture - clumping?

[Mina]

Hi
i have several packets of dry culture that I have been storing in my freezer since the day I purchased them.  I'm not too concerned with their viability, since I was told that they can extend past their expiry date if kept that way...I hope 

I've since opened a few packets to make various cheeses.  Once opened I quickly vacuum bagged them making sure all the air was out. I have noticed that on more than one occasion that as I take out the required amount from the packet, it will start to clump up.  I'm assuming this is because it is starting to 'thaw'?  I did have a problem with this one batch where the culture did not rehydrate well when introduced to the milk vat.  Some remained in a clump.  I had to stir quite a while and I managed to get it thoroughly mixed.
So - two questions:
1) Is there a better way to handle the packets?  Should I remove the dosage and allow it to sit at room temp for a while?
2) Can I pre-hydrate in some warmed milk in a sterile cup just prior to adding to the rest of the milk in the vat?

Thanks!