At least one million children and adults in the United States are allergic to sesame, an ingredient used in everything from hummus to snack bars, researchers reported on Friday.

The finding indicates that sesame allergy is more prevalent than previously known, al though still far less common than peanut allergy. But sesame is not among the allergens that the Food and Drug Administration requires manufacturers to list on food labels.

“Sesame allergy is becoming a common allergy in the U.S.,” said Dr. Ruchi S. Gupta, a professor of pediatrics at Northwestern Medicine in Chicago and senior author of the study, which was published in the journal JAMA Network Open . “The impact on over a million people in the U.S. is significant.”

The study relied on online and phone survey responses from 40,453 adults and 38,408 children. People who have had at least one symptom of sesame allergy made up an estimated 0.23 percent of the population, Dr. Gupta and her colleagues found.