Q:

Baked potato okay after sitting in the oven all night vs. Botulism or other risk?

Sometimes I forget the potatoes in the oven when there's enough going on. And there they are again - baked last evening, they sat through the oven's cool-down and then through the night. 
Should they be re-baked for safety? (That might just produce inedible potato-pucks.) Or is this a "cut your losses" situation? 
Thanks!

A:

You could probably leave a baked potato sitting at room temperature for days and it would still be safe to eat as long as it wasn't contained in a sealed container. But notice I said "probably." That's not the stance of food safety experts, and I would never serve other people something I'd left sitting at room temperature for so long. 
Note that if you wrap your potatoes in foil to bake them, it's a different matter altogether. Thirty people in El Paso, Texas discovered this the hard way in 1994:
https://www.ncbi.nlm.nih.gov/pubmed/9652437

In April 1994, the largest outbreak of botulism in the United States
  since 1978 occurred in El Paso, Texas. Thirty persons were affected; 4
  required mechanical ventilation. All ate food from a Greek restaurant.
  The attack rate among persons who ate a potato-based dip was 86%
  (19/22) compared with 6% (11/176) among persons who did not eat the
  dip (relative risk [RR] = 13.8; 95% confidence interval [CI],
  7.6-25.1). The attack rate among persons who ate an eggplant-based dip was 67% (6/9) compared with 13% (241189) among persons who did not (RR
  = 5.2; 95% CI, 2.9-9.5). Botulism toxin type A was detected from patients and in both dips. Toxin formation resulted from holding
  aluminum foil-wrapped baked potatoes at room temperature, apparently
  for several days, before they were used in the dips. Consumers should
  be informed of the potential hazards caused by holding foil-wrapped
  potatoes at ambient temperatures after cooking.

Can you re-bake the potato to make it safe? The short answer is no, as explained by the accepted answer to this question. Although the botulinum toxin is destroyed by heating to 85C/185F for 5 minutes, there are other more hardy bacterial toxins that can't be destroyed short of turning the potato into a cinder.
The US Department of Agriculture, which tends to be ultra-conservative with food safety, has this to say about your potato:
https://www.stilltasty.com/fooditems/index/18081

How long can cooked potatoes be left at room temperature? Bacteria
  grow rapidly at temperatures between 40 °F and 140 °F; cooked potatoes
  should be discarded if left out for more than 2 hours at room
  temperature.

So when you get up in the morning and discover a potato in the oven, the only safe thing to do is toss it. Considering that a potato costs about 15 cents (US) in most of the world, why would you risk otherwise?

