Citric acid is found naturally in citrus fruits, especially lemons and limes. It’s what gives them their tart, sour taste.
A manufactured form of citric acid is commonly used as an additive in food, cleaning agents, and nutritional supplements.

Manufactured citric acid is one of the most common food additive in the world.

It’s used to boost acidity, enhance flavor, and preserve ingredients 

Sodas, juices, powdered beverages, candies, frozen foods, and some dairy products often contain manufactured citric acid.

It’s also sometimes added to canned fruits and vegetables to protect against botulism, a rare but serious illness caused by the toxin-producing Clostridium botulinum bacterium.