Both fresh and canned tomatoes do contain citric acid. Similarly, any product that is tomato-based also contains citric acid. If a person is allergic to citric acid, he or she should read the food labels on products to ensure it does not contain this substance.
Citric acid is found in many other foods, such as pineapple, cherries, citrus fruits, sourdough breads and canned goods. Citric acid is a preservative added to products like soda, mayonnaise and fruit preserves. It also is found in many different types of restaurant foods.
It is an organic acid that has the molecular formula of C6H8O7. It has a boiling point of 307degrees Fahrenheitand is soluble in water and ethanol.