so clean (that) (one) could eat off the floor(s)
Of a room, house, restaurant, etc., so clean and hygienic that one could hypothetically eat directly off the floor without getting sick. I want this place to be so clean you could eat off the floor! The health inspector was impressed. He said the whole kitchen was so clean that you could eat off the floors.
so clean you could eat off the floor
[of a room or a house] very clean. Her kitchen is so clean you could eat off the floor! It's so clean here you could eat off the floor. I prefer a little mess, myself.