The sponges of our kitchen are very useful for the cleaning of the same. But it can also be a deposit of germs, because most of the time it is wet and in contact with different foods and liquids.
Dip the sponge into a hot water mixture with a bleach of 3 to 5 minutes.
Place it inside the dishwasher in a hot water cycle.
Place in a solution of water, bleach and lemon juice, for one minute inside the microwave at maximum power.
With these simple methods you will eliminate the bacteria that can form in the interior of the same and that can affect the health of you and your family.