Study: Quantity of Peanut Protein Found in Common Environments


Sufferers of peanut allergy avoid contact with the allergen at all costs in order to prevent life-threatening reactions from occurring. Simply ingesting or breathing trace amounts or touching a trace amount of the allergen and then touching one’s eyes, nose or mouth can result in a severe reaction or anaphylaxis.

Researchers from the Mayo Clinic investigated how much peanut trace could be found in public environments and presented their findings at this year’s annual meeting of the American Academy of Allergy, Asthma & Immunology (AAAAI).

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Dr Jay Jin“Clinicians often make avoidance recommendations without direct evidence of the amount of peanut or peanut exposure in these environments,” primary author Jay Jin, MD, PhD, said.  “So we quantified aerosolized and surface levels of Ara h2 – one of the peanut proteins associated with food allergy – in common, public locations hoping to provide evidence-driven recommendations.”

Using personal zone breathing samplers for 1 hour, large air samplers for 15 minutes, and swabbing surfaces with special membranes, peanut protein was extracted and analyzed from common public environments. The protein content reported in nanograms per milliliter varied widely depending upon the circumstances:

  • During active shelling of peanuts, 1.4ng/mL of trace was detected by the large air sampling equipment, though none was detected by the personal zone detectors in areas where unshelled peanuts were available;
  • On table surfaces in restaurants that offered peanuts, 41.1ng/mL of trace was detected vs. 0.77ng/mL at restaurants that did not offer peanuts;
  • 0.75ng/mL was detected on library tables;
  • A whopping 11,126.7ng/mL was detected at the topping bars of frozen yogurt shops.
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“Interestingly, we found an average of 13.5 ng/mL of Ara h2 on airplane tray tables when peanuts were not even served during the flight,” Jin explained. During flights where peanuts were available, tray table surface averages climbed to 175.3 ng/mL of Ara h2 after mid-flight service with peanuts.

“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,” Jin said.

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Dave Bloom
Dave Bloom
Dave Bloom is CEO and "Blogger in Chief" of

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