Allergic reaction after consumption of "meat-free chicken” (Quorn mycoprotein) by a patient with mold allergy

Authors: M. Sandhu, M.D., Allergist/Immunologist; R. Hopp, D.O., Allergist/Immunologist
Reviewer: V. Dimov, M.D., Allergist/Immunologist and Assistant Professor at University of Chicago

A 14-year old African American male had a suspected allergic reaction while eating “meat-free chicken” and a vegetable stir fry. The allergic reaction manifested within 2-minutes as throat irritation followed by generalized pruritis, difficulty breathing, lip, tongue, eye and laryngeal edema.

The reaction required an emergency room visit and overnight hospitalization. While in the hospital, he received 2 doses of subcutaneous epinephrine, intravenous corticosteoids (methylprednisolone, Solu-Medrol), H1- blocker (diphenhydramine, Benadryl) and H-2 blocker (famotidine, Pepcid). After 24 hours of observation, he was discharged.

The patient presented to the allergy clinic two months after the allergic reaction. He and his mother were uncertain of the contents of the stir fry. He did recall sampling the “meat-free chicken”.

Past medical history (PMH)




Physical examination

Stable vital signs (VSS).
Skin: no rashes, keratosis, excoriations, or lichenifications.
HEENT: normal. Eyes had no conjunctival injection or swelling, ears had no fluid or inflammation behind the TMs, nose had no mucosal edema or discharge.
Chest: clear to auscultation bilaterally (CTA (B)).
CVS: Clear S1S2.
Abdomen: Soft, non-tender, non-distended with normal bowel sounds (NT, ND, +BS).
Extremities: no cyanosis, clubbing or edema (c/c/e).

What diagnostic tests would you suggest?

Immediate type hypersensitivity skin tests to commercial food allergens (Hollstier Stier 1:20) demonstrated a negative reaction to soy and +1 positive reactions to corn and eggs.

What happened?

The patient's mother was asked to bring the product he ate during the follow-up appointment in one week.

The patient returned the following week with the product. It was a meatless, soy-free mycoprotein with egg binder. A skin test to the mycoprotein (100 mg in 2 ml normal saline) produced a 30 x 20 mm wheal and 100 x 100 mm flare (positive reaction).

Skin testing to molds was positive, including Fusarium vasinfectum, Alternaria tenuis, and to a lesser extent Aspergillus fumigatus. The Fusarium reaction was particularly "aggressive" with a 10 x 12mm wheal and 40 x 40mm flare with pseudopod formation.

Final diagnosis

Type I Hypersensitivity Reaction to Ingestion of Mycoprotein in a Patient With Mold Allergy.

Mycoprotein is a food made by continuous fermentation of the fungus, Fusarium venenatum (fungal family, fusarium genus). The fungus is grown in a large fermentation tower to which oxygen, nitrogen, glucose, minerals and vitamins are added. After harvesting, the fungus is heat treated to reduce its RNA content to the WHO recommended levels before being filtered and drained. The resulting sheet of fungal mycelia is mixed with egg albumin which acts as a binder. The mycoprotein is then textured to resemble meat.


Mycoprotein is marketed as Quorn. Quorn may be purchased as chunks, mince, sausages, burgers, fillets and is found in a wide array of frozen ready meals such as pies, curries and casseroles. In the United kingdom it enjoys around 60% of the meat-replacement food market, with annual sales of around £95 million. Mycoprotein was introduced in the USA in 2002. Approximately 1/140 000 consumers report adverse reactions after eating Quorn. Few case reports have been published describing the type I hypersensitivity reaction of ingested mycoprotein. Crossreactivity studies have shown that mycoprotein shares common allergenic determinants with molds such as Aspergillus fumigatus, Cladosporium herbarum, Alternaria alternate. The most likely allergenic determinant is the 60S ribosomal protein P2, which was identified as allergen Fus c 1 from Fusarium culmorum.

Related reading

Anaphylaxis to ingested molds in a mold-allergic patient. AAAAI, 2011.

Type I Hypersensitivity Reaction to Ingestion of Mycoprotein (Quorn) in a Patient With Mold Allergy. Manbir Singh Sandhu M.D., Russell J. Hopp D.O., FAAAAI, FAAP. Pediatric Asthma, Allergy & Immunology. March 2009, 22(1): 5-6. doi:10.1089/pai.2008.0518.

'Quorn' Meat Substitute Raises Allergy Concern. WSJ, 2011.

Infectious Fungus Common In Household Drains (Fusarium) - NPR, 2011. "Meatless chicken" (Quorn) is made of Fusarium.

Published: 03/19/2010
Updated: 11/30/2011

Comments from Twitter

@sarahjchapman: well isnt it mold anyway? its black slime made in vats, skimmed and bleached anyway, often has egg white added. Isn't it a mold so has links to mold allergy? i suppose its a new type of food to go into the food supply. I have heard that there are no pictures on net of it 'growing' as its so disgusting. we avoid mainly due to egg allergy as well. Obviously egg allergy more common, but can grasp idea of a up and coming new allergen in form of quorn.

@AllergyNet: Valuable case. New to me. Just checked, Quorn launched in Australia last year.

@DrVes: WSJ interviewed me last week about allergy to Quorn (different from corn) - see the report here: - It was published by 2 of my colleagues, UpToDate now quotes it in the section about quorn allergy - very few reports so far. Apparently the Quorn label does not mention anything about mold allergy...

@sarahjchapman: it wouldn't , apart from allergy wouldnt mention the 'mold' aspect in case it put off consumers. I wonder how many people have had cross reactive reaction to quorn and not connected reaction to it?

@IgECPD4: It's not quite the same thing but I had a patient with anaphylaxis to quinoa--a "new" gluten free grain from South America.

@scanman: I wonder how long it will be before this meat substitute 'vegetarian' fungus based Quorn is available in India


Anonymous said...

I had an allergic reaction to a Quorn product I ate yesterday..(turkey.) Several hours after eating, my face became slightly pink.
I thought it was from an exfoliating cream I had just used.
However, this morning my face, eyes & lips are pink & swollen. I suspect the Quorn as I have had nothing else different than usual foods I always eat. I have discovered I am allergic to sulfites and nitrates, and I think chocolate, possibly cheese has caused hives in the past. I will add to this list FUNGIS/MOLDS.

Michael F. Jacobson, Ph.D., Center for Science in the Public Interest said...

The Center for Science in the Public Interest (CSPI) has collected 1,700 reports of adverse reactions to Quorn, including severe vomiting, hives, and anaphylaxis. See for more information or to file an report.

The statement above that 1/140,000 people are sensitive to Quorn is wrong. The company has used that figure, based perhaps on the number of reports it has received, but CSPI's telephone survey of consumers of Quorn in the UK found that about 5% of people reported being sensitive to the product.