I don't believe the lower than deep fat frying temp is a concern. One I'll have the box set to 250f. And cooking time for chicken is much shorter than most meats.
Also we use dairy in Sous Vide cooking at much lower temps for long times. A low temp for a long enough time actually pasteurizes the product. Too short of a cook time at a low temp would be dangerous.
And yes understand about Salt and umm, Brine... Just wondering if other properties of buttermilk lead to much the same effect, acids, proteins??? Where is that food scientist?
And what bugs can survive in buttermilk, it's so blasted nasty