My in-laws have a practice in which they make soup with the lid on the pot, turn off the heat, and leave the pot on the stove without lifting the lid until the next day when they eat it.

Their claim is the heat destroys any existing pathogens, and the lid prevents outside contamination, and that the contents are thus safe to consume.

I found this all a bit dubious. It seems to me that if the lid did have such a good seal, there would be a pressure differential giving significant resistance when trying to remove it.

Is this a safe means of short-term room-temperature preservation?