I have stumbled on a local supplier of Mesophilic DVS culture, however his supply is just sitting on the shelf and is at least a year old. It is marked as "shelf stable" however it's not been stored in the freezer.
The brand is Mad Millie and it's packaged in the UK, sold in the US.
How can I tell if it's any good? He has a small case of this and wants to know if he should trash it or not.
I don't know how I can tell, but I thought perhaps measuring PH would be one way since this is an acidification stage.
TIA