PH regulator, also known as pH regulator, acidity regulator or pH control agent, is a kind of food additive used to adjust or maintain pH value (acid or alkali). Acidity regulator can be organic or inorganic acid, alkali, neutralizer or buffer. Acidity Regulators are identified by their E-codes, such as E260 (acetic acid), or listed under "food acidity agents". The frequently used Acidity Regulators are citric acid, acetic acid and lactic acid. Sodium carbonate and potassium carbonate can be used in flour food. Hydrochloric acid and sodium hydroxide belong to strong acid and strong alkaline substances, which are corrosive to human body. They can only be used as processing aids and should be neutralized before food processing.