Omelet's thread has taken on a life of its own, so I thought I would
post this separately:

In her "Crockery Cookery," Mable Hoffman's co-author Howard Fisher
measured the temperature vs. time for some 20 slow cookers, at both
the low setting and the high. He filled the pots with cooking oil to
extend the curves above the boiling point of water.

Anyhow, set to LOW, it took roughly 2.5 to 3 hours for the (Rival)
Crock Pots to reach the boiling point of water. After 1 hour on LOW,
the original Crock Pot only heated the oil to 140F.

So quite possibly her food was under safe temperature the entire time
it was in the Crock Pot.