In the food industry, citric acid is often used as a flavoring agent to increase the acidity of foods and improve their taste. For example, the addition of citric acid to the preparation of foods such as candies, cookies, breads, jams, beverages, and canned foods can make the food taste better and promote appetite. In addition, citric acid is used as a preservative that inhibits bacterial growth and improves the color stability of foods, thereby extending their shelf life. Citric acid also plays an important role in the cosmetics industry. It acts as a mild cleanser, helping to remove dirt and oil from the surface of the skin, leaving it refined and smooth. In addition, citric acid softens the stratum corneum to some extent and improves skin roughness. In addition to the food and cosmetic industries, citric acid has a wide range of applications in other fields. For example, in cellulose production, citric acid can be used to make biodegradable materials, which has important environmental applications. In addition, citric acid is used in the production of liquid fertilizers, as it forms a protective layer on plant roots, preventing the invasion of pathogens and promoting plant growth and development.