I prossed milk for a few years, when a truck lode of milk came in we tested is fresness and culture stability, if it was tanted/sower we wood add bakeing soda to fresen it back so it could be prosed would add 14 day's to end date.
It would be aroud a table spoon of soda for each gallon,
Hope this helps you guys you can only do this once to fresen it, we never pore out sower milk .