Soup can go sour for many reasons. You can simply forget to put it in the refrigerator and the next morning you will have to pour the remains down the drain.
It may also happen that a spoon forgotten in the soup or improperly added greens will shorten the shelf life of the finished dish and a strange smell will appear.
If this is the only issue, then you can save a dish that is starting to spoil, eliminate the smell and eat it without harm. This is what experienced cooks say.
It is possible that during the preparation of the soup some ingredients were added that do not require cooking, after which the housewife did not bring the contents of the pan to a boil.
This can happen even after fresh herbs have been poured into the pan and the heat has been immediately turned off.
In the morning the soup may already start to smell of something not so fresh. This can still be fixed.
But if stale ingredients were used, as they say, meat with a smell or other products of dubious quality, then it is better not to take risks.
All that remains is to take the pan out of the refrigerator, place it on the stove, bring the contents to a boil and boil for 4-5 minutes.
This will be enough to destroy the beginnings of the pathogenic environment and get rid of the unpleasant odor.