No person shall serve colored oleomargarine or colored margarine at a public eating place unless a notice that oleomargarine or margarine is served is displayed prominently and conspicuously in such place and in such manner as to render it likely to be read and understood by the ordinary individual being served in such eating place or is printed or otherwise set forth on the menu in type or lettering not smaller than that normally used to designate the serving of other food items or each separate serving is accompanied by labeling identifying it as oleomargarine or margarine or each separate serving thereof is triangular in shape. No person shall serve colored oleomargarine or colored margarine as a spread or in melted form as a substitute for butter unless menus or other forms of notice are made indicating that oleomargarine or margarine is being served.