Many Common Food Allergens Found at Lower Levels in Schools Than in Homes

By Lisa Rapaport

July 06, 2021

(Reuters Health) - Milk, egg, peanut and tree nut allergens are detectable in dust samples from table surfaces and floors in U.S. elementary schools, although at lower levels than in student homes and low enough that the risk of anaphylaxis is minimal, new research suggests.

In a sub-study of the School Inner-City Asthma Study-II, researchers examined levels of milk, peanut, cashew, hazelnut and egg allergens found in 98 floor dust samples and 103 table wipe samples from classrooms and cafeterias in 18 elementary schools as well as kitchen floor and bed dust samples from 90 student homes.

Within the schools, milk and egg allergens were detected in all floor dust samples, and milk and peanut allergens were found in all the table wipe samples. Table wipe samples from cafeterias had significantly higher levels of milk, peanut, hazelnut, and egg allergens than samples from classrooms.

Peanut allergen levels were lower in dust samples from homes of students with peanut allergies than in homes of students without peanut allergies, the study also found. Peanut allergen levels inside the schools of students with peanut allergies, however, were low and similar to levels found in homes of students with peanut allergies.

"This study showed that food allergens are ubiquitous," said senior study author Dr. Wanda Phipatanakul, a professor of pediatrics at Harvard Medical School and director of the research center for asthma, allergy, dermatology, rheumatology, and immunology at Boston Children's Hospital.

However, the "study provides important real-world data that it is highly improbable that enough environmental food allergen in schools could be ingested to precipitate a systemic reaction, or that cutaneous exposure to minute amounts of these food proteins could cause a clinical reaction," Dr. Phipatanakul said by email.

One limitation of the study is that SICAS-II wasn't designed specifically to examine differences in food allergen levels in schools and homes, or differences in food allergen exposure at home or school for allergic versus non-allergic children.

Results from elementary schools and homes of students in the inner-city in the northeast also may not be generalizable to other populations, the study team notes in the Journal of Allergy and Clinical Immunology: In Practice.

Still, the results point to the difficulty of regulating food allergens in public places like schools, said Dr. Ruchi Gupta, director of the Center for Food Allergy & Asthma Research at the Northwestern Feinberg School of Medicine in Chicago.

"Even if a school is free from certain foods, we cannot check every student that comes in for what they are bringing," Dr. Gupta, who wasn't involved in the study, said by email. "It is important to discuss the food allergy with school staff and take precautions for avoidance."

Clinicians should also ensure that students have an action plan, epinephrine, and depending on age, be aware of allergic reaction symptoms and what to do if they have a reaction, Dr. Gupta advised.

"Education on avoidance, not sharing food, and reading labels is also very important," Dr. Gupta said.

SOURCE: Journal of Allergy and Clinical Immunology: In Practice, online June 24, 2021.