When we think of food allergy, the first thing we remember is that there is a reaction if the person ingests the food and that by removing it from their food they will be safe. However, it is important to point out that, depending on the sensitivity of each one, food does not need to be ingested to trigger a reaction; touching the allergenic food, kissing or touching someone who has recently eaten it can be all it takes to cause an allergic reaction. (1)

Contact between lovers with food allergies

A passionate kiss can be an indirect way of ingesting the allergen, through contact with the saliva of another person who has consumed a food or drug that contains the allergen. (2.3)

Experts have documented that around 12% of food allergy sufferers develop a reaction after close contact with someone who has eaten a food they do not tolerate, namely through a kiss. (4) There are even reports of anaphylactic reactions triggered by a kiss between lovers a few hours after the non-allergic person has ingested the allergenic food. (1)

Contact parents/children and grandparents/grandchildren with food allergies

Even a simple kiss on the cheek, between parents and children, grandparents and grandchildren or between friends, can cause a reaction by contact that can range from localized symptoms on the skin to more serious and generalized symptoms. (3.5)

A study in peanut allergy sufferers found that 19% of allergic reactions were due to skin contact. (1)

How long does a food allergen stay in saliva?

A study was also carried out to assess the persistence of allergen in saliva after food ingestion and the effectiveness of mouthwash to reduce the amount of allergen in saliva.

Without any washing, in 13% of the subjects it was still possible to detect the allergen about 1 hour after the meal. Only after several hours, the allergen became undetectable in the saliva.

All mouthwash methods used in this study, namely, brushing teeth, brushing and rinsing, rinsing, chewing gum, were effective in reducing the allergen content in saliva by 95%, but about 40% of saliva samples still contained a small amount of detectable allergen.

Therefore, in more severe allergies where there is a reaction to traces, it is important to take into account the risk of reaction through a kiss even after washing the mouth, being the safest and most effective procedure to wait a few hours after ingesting the allergen. . (6)

Tips to avoid reactions when you are in contact with someone with a food allergy

When you are around someone who has a food allergy, avoid eating anything that contains the allergen in question. If you do, wash your hands and mouth afterwards to avoid touching reactions.
Do not share cutlery, plates, cups or napkins that may have touched the allergen (3).
If an allergen comes into contact with your skin, wash it off to avoid accidentally touching your mouth, eyes, or nose (where it can cause a more serious reaction). For this reason, it's important to wash your hands before eating or touching your eyes, nose, or mouth, especially in young children (3).

At Fidu we develop alternative recipes to create products that are more similar to traditional ones, so that all family and friends, with or without allergies, can share and consume without distinction or worries.

Fidu products do not contain the 14 main allergens or traces, and can be consumed by everyone, even the most sensitive.

Try our products and enjoy!


(1) Steensma DP. The kiss of death: a severe allergic reaction to a shellfish induced by a good-night kiss. Mayo Clin Proc. 2003 Feb;78(2):221-2. doi: 10.4065/78.2.221.

(2) SPAIC Food Allergy Interest Group. Food Allergy: Concepts, Advice and Precautions. Edited by Célia Costa et al., 1st Edition, Thermo Fisher, 2017.

(3) Pistiner, Michael, and Jennifer LeBovidge. Living Confidently with Food Allergy - A Guide for Parents and Families. 2nd Edition, Food Allergy Canada, 2015.

(4) Eriksson NE, Möller C, Werner S, Magnusson J, Bengtsson U. The hazards of kissing when you are food allergic. A survey on the occurrence of kiss-induced allergic reactions among 1139 patients with self-reported food hypersensitivity. J Investig Allergol Clin Immunol. 2003;13(3):149-54.

(5) Tan, Belen M., et al. “Severe Food Allergies by Skin Contact.” Annals of Allergy, Asthma and Immunology, vol. 86, no. 5, 2001, pp. 583–86.

(6) Maloney JM, Chapman MD, Sicherer SH. Peanut allergen exposure through saliva: assessment and interventions to reduce exposure. J Allergy Clin Immunol. 2006 Sep;118(3):719-24.