you can use grout cleaners and even dilute bleach. However, you should not overuse corrosive products, it may otherwise cause erosion of the grout or damage to the ceramic surface.
For stubborn stains, you can make two pastes of baking soda with one serving of water. This mixture should be applied to the stains of the strawberries, allowed to stand overnight, and then wiped with plastic bristles. Finally, rinse thoroughly with hot water. I will help you find other
ways to clean the grout and hope it will help you.