Citric acid is a weak organic acid that occurs naturally in various fruits, especially in citrus fruits such as lemons, limes, oranges, and grapefruits. It is a white crystalline powder or granules with a sour taste. Citric acid is widely used as a food additive and preservative due to its acidity, refreshing flavor, and antioxidant properties.

Here are some key points about citric acid:

1. Food and Beverage Industry: Citric acid is commonly used in the food and beverage industry as a flavor enhancer, natural preservative, and pH regulator. It gives a tart taste to soft drinks, candies, jellies, and many other food products. It is also used as an ingredient in baking powders to create a leavening effect.

2. Preservation: Citric acid helps preserve the freshness and quality of various food and beverage products. It inhibits the growth of bacteria, molds, and yeasts by lowering the pH level, thereby increasing the shelf life of these products.

3. Cleaning and Household Uses: Citric acid is a popular ingredient in many cleaning products due to its excellent chelating properties. It can bind to metal ions, making it effective in removing limescale, rust, and stains. It is often found in dishwasher and laundry detergents, toilet cleaners, and descaling agents.

4. Personal Care Products: Citric acid is used in various personal care products such as shampoos, soaps, creams, and lotions. It can act as a pH adjuster, buffering agent, and preservative. It helps control the pH of the formulations and enhances the effectiveness of other ingredients.

5. Medical and Pharmaceutical Applications: Citric acid has medical applications as well. It is used in some medications as a tart flavoring agent to mask unpleasant tastes. It can also be used as an anticoagulant in blood transfusions and as a component of certain kidney stone treatments.

6. Industrial Applications: Citric acid finds applications in several industrial processes. It is used in the production of detergents, cleaning agents, and various chemicals. It is also used in the textile industry to modify dye processes.

It's worth noting that citric acid is generally recognized as safe (GRAS) by regulatory authorities such as the U.S. Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA) when used in accordance with approved guidelines.