Parents of peanut allergic children may worry about how much exposure to peanut protein can actually occur in places such as restaurants, or on commercial airplanes. The reason for their concern is that even trace amounts of peanut allergen can trigger severe reactions, including anaphylaxis, in allergic individuals.
Air and Surface Levels of Peanut Protein
Some researchers at the Mayo Clinic in Rochester, MN harbored the same concern, and decided to measure air and surface levels of the peanut protein Ara h2 in public locations.
“Clinicians often make avoidance recommendations without direct evidence of the amount of peanut or peanut exposure in these [public] environments,” said lead research author Jay Jin, Ph.D.
To assess levels of Ara h2, the scientists used Teflon membranes to wipe surface areas, and exposed Teflon membranes to air samples. Captured peanut protein was extracted from the membranes using a phosphate buffered saline solution, and Ara h2 levels were measured.
Trace Amounts Found
The Ara h2 that researchers found is measured in ng/mL, or nanograms per milliliter:
- Large air samples picked-up Ara h2 (1.4ng/mL) in eateries when peanuts were actively being shelled.
- In small, personal breathing zones within restaurants, where unshelled peanuts were available in dining areas, no airborne Ara h2 was detected.
- Restaurant table tops averaged 41.1 ng/mL of Ara h2; however, in places where peanuts were absent from the dining area, table surfaces had only 0.77 ng/mL of the peanut protein.
- Library table tops had a small amount of Ara h2 (0.75ng/mL).
- The counters in frozen yogurt stores had 11,126.7 ng/ML of Ara h2.
- When peanuts were not served during flights airplane trays averaged 13.5ng/mL of Ara h2; when peanuts were served inflight, airplane tray tops averaged 175.3ng/mL.
“Our research shows that peanut exposure in public settings is most likely to occur by contact with surfaces harboring allergens rather than by inhalation, even in peanut-rich environments. It also reinforces the practice of regularly cleaning common surfaces, especially for individuals with a peanut allergy,” says Jin.