Citric acid is mainly used as acidulate, flavoring agent, preservative and antistaling agent in food and beverage industry. It is also used as antioxidant, plasticizer and detergent in chemical, cosmetics and cleaning industries. Citric acid is an excellent chelating agent, binding metals. It is used to remove limescale from boilers and evaporators. It can be used to soften water, which makes it useful in soaps and laundry detergents. By chelating the metals in hard water, it lets these cleaners produce foam and work better without need for water softening. Citric acid is the active ingredient in some bathroom and kitchen solutions. A solution with a 6% concentration of citric acid will remove hard water stains from glass without scrubbing. In industry, it is used to dissolve rust from steel. Citric acid can be used in shampoo to wash out wax and coloring from the hair. In food industry widely used as sour agent, solubilizer, buffering agent, antioxidant, removing fishy smell removing sweetening agent, chelating agent, its specific purpose, numerous enumeration.