<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">USDA recommends a water activity below 85% to be considered safe. </div></BLOCKQUOTE>
If they do this would be moot. (It sounds a bit like their simplified dumbed-down info they proffer to consumers rather than their info for pros.
When dealing with pathogens on an HACCP level, it's the combination of results - pH, aw, etc. - and the process getting there - the procedures used in making the sausage, e.g., the cleanliness during its making, ingredients used, temp of ingredient during processing, temp post processing, etc.
Aw < 92 in one way to deal with most common fb pathogens - Clostridia spp, Listeria. Vibrio, Salmonella, Campylobacter. S. aureus does require a much lower aw, but that's only one control. S. aureus does not compete well with spoilage bacteria (which is why it is less of a concern on raw foods, much more on cooked foods, especially those that are handled after cooking - like meats turned into salads, pulled pork, et al.) and needs sufficient time at sufficient temps to outgrow till the point sufficient numbers are reached. It is at that point toxin is produced.