The use and value of salt

[Caratacus]

I did a search of the Vindolanda tablets and found this:

December, through Audax, of salt, pounds 85+, asses 12+ (?)

Does the tablet say anything about how many men this amount of salt was bought for? It could possibly have been an amount for an entire century - or an amount for a specific purpose, such as salting down meat for the winter stores? Even so, it does seem a trivial price for such an important dietary commodity - it's not even a full denarius. This amount of salt might also be a year supply.

Mike Thomas
(Caratacus)