@chickenlittle: Good point about thermoses. I hadn't thought of that. Note to self: no bleach allowed in the Nissan.

@Art in Fl: Generally, I'm not going to give up using chlorine bleach. There are too many situations where the "big nuke" is absolutely necessary. But I'll keep a closer eye on concentration and duration. Especially important since I'm seeing household bleach with concentrations ranging from 4% - 6% on the shelf, so it's really important to do the math.