A complete stranger? I wouldnt take that risk. You dont know what they might have put in the food or what conditions it was made in. Accept it to be polite then throw it away when they are gone.
Is it ok if I accept the food from a stranger? I don't know him/her just a small meeting and good gesture from his/her side?
no.
No I wouldn't.
In the distant past it might have been.
But no longer reliable. Do not !