With souffle it is not a good idea to make it too far ahead because it will not rise as it should if it is prepared too far ahead. Rather make it and bake it immediately after having prepared it.
It's generally not safe to eat sweet potatoes that have been left out at room temperature overnight, as bacteria can grow on cooked foods left unrefrigerated for more than two hours. If they were cooked and left out for an extended period, it's best to discard them to avoid the risk of foodborne illness. Always refrigerate leftovers promptly to ensure safety.
I'd imagine that if the casserole contained dairy or dairy products such as milk, cream, or cheese, then it may have a hard time staying fresh without refrigeration. The lactic acid bacteria added to milk after pasteurization ferment lactose at room temperature, causing a sour taste and residual curdling. Refrigeration is never a bad idea if you're in doubt!
Sweet Potatoes are a good source of dietary fiber, vitamin A, vitamin C, thiamin, riboflavin, vitamin B6, folate, magnesium, phosphorus, potassium and manganese." This stellar vitamin profile puts them in the same league nutritionally as spinach and collards.
no
No, the oven was not left on overnight.
They may be unsafe to eat if left out overnight and should be thrown out.
does squash spoil if left overnight or two days
Don't use it. Throw it away. It might not appear spoiled in the traditional sense (moldy, bad odor, slimy), but bacteria could have grown and toxins could have formed that could make someone sick.
No. It is not safe to eat turkey left out overnight in any container.
No, it may not be safe to eat after being left out overnight.
Yes, I accidentally left the milk out overnight.
No. Stew left out overnight would not be safe to eat, covered or not - unless where it was left out was as cold as a refrigerator.