Colour coding is based on the idea of designating particular cleaning products and processes to consistent colour schemes. Its purpose is to segregate equipment and procedures in order to prevent cross contamination in the home and workplace. Follow the 'Golden Rules' below to use colour coding successfully and help protect human health. Red High Risk Sanitary Areas such as toilets, urinals and washroom floors. Blue Low Risk General Area such as desk tops, window ledges, dusting & polishing. Green Catering Departments Food processing, food services & bar areas. Yellow Washbasins & surfaces including tiled walls, mirrors, glass & metal.