Propionic Acid (CH₃CH₂COOH) is a naturally occurring carboxylic acid with a sharp, pungent odor. It appears as a clear, colorless liquid and is miscible with water, ethanol, and ether. Propionic acid is widely used as a preservative in food and animal feed, as well as in the production of herbicides, plastics, pharmaceuticals, and flavoring agents. Due to its antifungal and antibacterial properties, it is particularly valuable in mold inhibition in stored grains and baked goods.