Low levels of food allergens commonly detected in students’ environments

Published: June 23, 2021

The prevalence of IgE-mediated food allergy (FA) is increasing, with milk, egg, peanut, and tree nuts being the most common triggers in pediatric patients. Small amounts of these allergens can accumulate in the dust which collects on table surfaces and floors. For people with known FA, reactions from food protein in the environment are a concern. Prior studies have evaluated environmental food allergen exposures in different environments. However, children spend the most of their days in school, and little is known about environmental food allergen exposure there, especially for foods other than peanut.

In this sub-study of the School Inner-City Asthma Study-II, published in The Journal of Allergy and Clinical Immunology: In Practice, Maciag et al evaluated the detection rates and levels detected of the major food allergens: milk, peanut, tree nuts and egg, in table wipes and floor dust in inner-city schools and homes. They then determined the difference in food allergen levels in locations across the schools in different samples and compared the distribution of food allergen levels across home and school environments of children with and without IgE-mediated FA. Overall, 103 table wipe samples and 98 floor dust samples from cafeterias and classrooms in 18 elementary schools along with home kitchen floor and bed dust samples from 90 students were analyzed by multiplex array.

Food allergens were readily detectable on tables and floors in elementary schools but at levels lower than in students’ homes. In schools, milk and peanut were detected in every table wipe sample; and milk and egg were detected in every floor dust sample. Table samples from cafeterias contained significantly higher levels of milk, peanut, hazelnut, and egg, than table samples collected from classrooms. Cafeteria floor dust samples contained higher levels milk allergen than classrooms. Although limited by small sample size, peanut allergen level was lower in dust from homes of the five students with peanut allergy compared to levels from homes of the 85 students without peanut allergy. Reassuringly, peanut allergen in the school environments of peanut-allergic students was not significantly different than in their homes. Peanut-restrictive policies did not consistently reduce environmental peanut exposure in schools. The low levels of detectable environmental food allergens in schools are unlikely to result in severe allergic reactions.

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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