Citric Acid
The short version
A weak organic acid found in citrus fruits, used to add tartness and act as a preservative.
It's widely considered safe at the amounts used in food, so we mark it green. The Safety section below has the details.
Where it comes from
First isolated from lemon juice by Carl Scheele in 1784. Industrial production today relies on fermentation by the mold Aspergillus niger from corn or sugar feedstocks.
How it's used
Used in soft drinks, candies, jams, dairy products, and canned vegetables. Provides tart flavor, lowers pH for preservation, chelates metal ions, and acts as a synergist with antioxidants.
Safety profile
No ADI required. Naturally occurring central intermediate in human energy metabolism (the citric acid cycle). High concentrations may erode tooth enamel over time.
Physical & chemical properties
Colorless crystalline solid, very soluble in water. Triprotic acid with pKa values of 3.13, 4.76, and 6.40.
Regulation worldwide
Permitted globally with no quantitative restrictions for most applications.
Educational information only. Not medical or dietary advice.