Q:

9/20/2012
A local science teacher informed me she has some students interested in a research project relating to allergies and food residues left at places such as restaurants and cafeterias; they are investigating into what types of tests are available to detect the presence of food allergens (e.g. peanut) on surfaces such as tables, as well as what treatments are best at getting rid of such residue.

The teacher asked me if there is a test to detect food allergens on surfaces, but I do not know of any such tests available to detect the presence of food allergens on surfaces. My thought is that disinfecting wipes (e.g. Clorox Bleach wipes) can get rid of food allergen residue on surfaces; however I would greatly appreciate your input regarding this, which I could then pass on to the teacher, as this would be an interesting project for these students to pursue. Thank you.

A:

Thank you for your inquiry.

There are actually a number of commercial tests to detect food allergens. These have been published for the most part in literature outside of allergy journals such as Food and Agricultural Immunology. There is actually fairly voluminous literature in this regard. I copied below two examples of such tests. They are usually employed to detect cross contamination of foods or food products. However, the same techniques can be employed to detect allergens on surfaces.

There is not a large amount of data, to my knowledge, available on the effect of cleaning surfaces and washing hands regarding the removal of food allergen. However, the best data we have indicate that routine cleaning procedures are highly effective. I have copied for you below an abstract from an article, published in The Journal of Allergy and Clinical Immunology, that looked at this issue. As you can see, usual cleaning techniques should be highly effective in removing allergens from tables, other surfaces, and hands. In addition this article notes a method to detect food allergen as well.

Thank you again for your inquiry and we hope this response is helpful to you.

Determination of Peanut Traces in Food by a Commercially-available ELISA Test Food and Agricultural Immunology
Volume 11, Issue 3, 1999
Abstract
Peanuts are one of the most important food allergens. The unintended ingestion of peanut has caused severe allergic reactions and even deaths in sensitive individuals. Specific methods with sensitivities in the low ppm range are necessary to check whether a food contains relevant amounts of peanut protein. Based on a commercially-available ELISA test, a test protocol was established for the detection and semi-quantitative determination of peanut traces in a wide range of products, including chocolate and chocolate confectionery, ice cream and bakery goods. The test was rendered semi-quantitative by including a standard curve prepared from different peanut materials and by adapting the extraction procedure. Using the extraction buffer supplied with the kit, only 2-3% of peanut protein added to dark chocolate could be recovered. By using a fish gelatine containing extraction buffer, recoveries of 60-90% and a detection limit of 2 mg peanut protein kg-1 product were achieved for this matrix. Comparable results were established for other products with similar values for extraction with or without fish gelatine. No false positive results were observed. With this a sensitive method is available for the determination of peanut traces in a wide range of raw materials and finished products. The detection limit of 2 mg peanut protein kg-1 product is satisfactory if compared to the lowest tolerable dose of peanut protein as determined in recent challenge studies.

Development of a rapid dipstick immunoassay for the detection of peanut contamination of food Food and Agricultural Immunology
Volume 9, Issue 1, 1997Abstract
Polyclonal antisera were raised to conarachin, the 7S globulin of peanut, Arachis hypogea. The antisera were of high titre and were specific for conarachin, showing no significant cross©\reaction with proteins from a range of nuts and legumes, as determined by immunoblotting and ELISA. A dipstick ELISA was developed using these antisera as both the capture and detector elements of the assay. The final steps utilized an avidin©\biotin detection system and tetramethylbenzidine as the substrate. The dipstick assay was highly sensitive, and employed a simple one©\step extraction method. It was able to detect as little as 0.01% (w/w) of peanut in marzipan and 0.1% (w/w) of peanut in chocolate. Roasted nuts were also detected, down to a concentration of 0.1% (w/w) in both foods. The dipstick assay also functioned with a range of foodstuffs, and readily indicated any that contained peanut. This method enables analysts to test, for the first time, for the presence of peanuts in food in a fast and easy©\to©\use manner. The availability of such technology makes the task of monitoring foods for contamination by peanuts readily achievable, providing the industry with an important tool for quality control of raw materials, processes and products. Increased testing will give consumers, particularly those sensitive to this potent allergen, increased assurance as to the safety of the food they eat.

Journal of Allergy and Clinical Immunology
Volume 113, Issue 5, May 2004, Pages 973¨C976
Distribution of peanutallergen in the environment
Tamara T Perry, MD, Mary Kay Conover-Walker, CRNP, Anna Pom¨¦s, PhD, Martin D Chapman, PhD, Robert A Wood, MD
Abstract
Background: Patients with peanut allergy can have serious reactions to very small quantities of peanutallergen and often go to extreme measures to avoid potential contact with this allergen.
Objective: The purpose of this study was to detect peanut allergen under various environmental conditions and examine the effectiveness of cleaning agents for allergen removal. A monoclonal-based ELISA for Arachis hypogaeaallergen 1 (Ara h 1; range of detection, 30-2000 ng/mL) was used to assess peanut contamination on cafeteria tables and other surfaces in schools, the presence of residual peanut protein after using various cleaning products on hands and tabletops, and airborne peanut allergen during the consumption of several forms of peanut.
Results: After hand washing with liquid soap, bar soap, or commercial wipes, Ara h 1 was undetectable. Plain water and antibacterial hand sanitizer left detectable Ara h 1 on 3 of 12 and 6 of 12 hands, respectively. Common household cleaning agents removed peanut allergen from tabletops, except dishwashing liquid, which left Ara h 1 on 4 of 12 tables. Of the 6 area preschools and schools evaluated, Ara h 1 was found on 1 of 13 water fountains, 0 of 22 desks, and 0 of 36 cafeteria tables. Airborne Ara h 1 was undetectable in simulated real-life situations when participants consumed peanut butter, shelled peanuts, and unshelled peanuts.
Conclusion: The major peanut allergen, Ara h 1, is relatively easily cleaned from hands and tabletops with common cleaning agents and does not appear to be widely distributed in preschools and schools. We were not able to detect airborne allergen in many simulated environments.

Sincerely,
Phil Lieberman, M.D.

AAAAI - American Academy of Allergy Asthma & Immunology