All items should be stored away from the walls and how many inches from the floor?

There are several reasons why all food, supplies, and equipment should be stored away from the walls and at least 6 inches above the floor. The biggest reasons are pests and cleanliness. Despite your best efforts, pests may still enter the establishment. Rats, mice, and cockroaches are able to climb and crawl almost anywhere. But other pests may find it difficult to reach items stored above the floor and away from the walls.
The floor is often the dirtiest place in the establishment. Storing items above the floor keeps them away from dirt, dust, and debris. It could also make cleaning underneath the shelves easier. Storing items away from the walls also makes for easier cleaning. It also prevents spiders from making webs or dirt and debris from accumulating in hard-to-reach spaces.