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JimHi Shuswap, you might know more about this than I do, but my understanding is that the acidity/ph is dependent on several things: Type of bugs that are in the starter culture, the amount of food (dextrose) they have in the formulation, the length of time they get to eat the food (length of fermentation) and the temperature of fermentation (the higher the temp the faster they convert dextrose to lactic acid).
Given those variables one can control the acidity of the sausage by putting less dextrose into the formulation, fermenting for shorter time or at lower temp. In general T-SPX is a milder type of culture used for European style dry sausage.
Some straight forward reading I found of this is from our friend Stanley Marianski:
http://www.meatsandsausages.com/sausage-types/fermented-sausage