Bananas do not contain citric acid. They are safe for people with citric acid sensitivities to consume although they can cause reactions in people who are allergic to latex.
While citric acid powder is a lung irritant and causes coughing when inhaled, the American Academy of Allergy Asthma & Immunology does not recognize citric acid as an ingested allergen. Citric acid forms a vital part of human metabolism and is present in every human body. It is also important to the formation and maintenance of bones. Citric acid's primary danger is causing tooth decay if ingested regularly by someone who does not practice proper oral hygiene.