The three-color towels in the canteen represent the cleanliness of food contact surface, indirect contact surface and cleaning utensils. The food contact surface refers to the surface of the article that is in direct contact with food; Indirect contact surface refers to the surface of items that are not in direct contact with food, but may contact with food, such as kitchen wall, kitchen floor, kitchen ceiling, kitchen utensils, etc. Cleaning utensils refer to articles used for washing, wiping and storage during cleaning, such as rags, brushes, detergents, etc. The three-color towels in the canteen are blue towels for food contact surface, red towels for indirect contact surface and white towels for cleaning utensils.