Citric acid is a naturally occurring weak organic acid abundant in citrus fruits such as lemons and limes. It serves as a key intermediate in the citric acid cycle (Krebs cycle) central to cellular energy production in aerobic organisms. Industrially, it is produced via fermentation of sugars by Aspergillus niger and functions as an acidulant, flavor enhancer, preservative, and chelating agent in foods, beverages, pharmaceuticals, and cosmetics. Its three carboxylic groups confer strong buffering capacity and metal ion sequestration properties. The compound appears as colorless crystals or white powder with a tart taste and is biodegradable with minimal environmental persistence.