Frankly, I don't think there's much difference in the outcome at those temps (and I use 131ºF for beef). And, yeah, bumping the temp a few degrees is prudent if you've got immune system issues to deal with. EnriqueB has argued for years here (sorry, no link handy) that there aren't as many studies at the lower temp as we'd like.
ETA: Here's a post by EB I particularly had in mind, which links to various earlier discussions of the lower limit issue.
ETA2: I use 131º for short cooks of beef. For long cooks, I don't go below 135º, in part because of this issue.
