Did you cook any soup and the soup is already having another taste and it is no longer fresh? What you need to do is to place that soup on fire and add just a piece of charcoal. Put a piece of charcoal in that food that got spoilt. If you do that, the charcoal you kept in that soup will help you to remove the bad taste and when you eat it, you will love your food again.
To prevent your soup from getting spoilt, its best not to put a spoon into a pot of soup while not hot, on the heat or still steaming. As sometimes you might get lucky, sometimes, you may not be lucky.
If a soup or stew is too salty, add raw cut potatoes. Discard them after they have cooked – they will have absorbed the salt.