Why is it not allowed to stack dishes in the dishwasher?

Proper cleaning and sanitization of dishes in a commercial dishwasher rely on effective water and sanitizer exposure on all surfaces. When dishes are stacked, it obstructs the flow of water and the sanitizer, preventing them from reaching all areas. This can lead to incomplete cleaning and sanitization, thus increasing the risk of bacteria and pathogens remaining on the dishes, which poses a health risk if used for food service. Ensuring that all surfaces are adequately exposed to cleaning and sanitizing agents is critical in maintaining food safety standards. This principle highlights the importance of proper loading techniques in dishwashing operations to ensure effective sanitation.