Several proteins in sesame seeds might be allergenic. Five of those proteins have been studied in detail. Among these there are two oleosins. Oleosins appear in spherical lipid bodies in the seeds and might be the cause of severe reactions reported from consumption of sesame seed oil.
Sesame seeds are used for the taste and for decoration in different food products like bakery goods, confectionaries, bread, hamburger bread, rice cakes, fish coating, pasta sauces, vegetarian dishes and pesto.
Labeling
The presence of sesame seeds and products thereof must always be declared see further in LIVSFS 2004:27 Livsmedelsverkets föreskrifter om märkning och presentation av livsmedel [in Swedish] (see link to the right). Sesame seed oil is not exempted from labeling.
Examples of methods of analysis
Sesame seed proteins can be quantified with commercial enzyme immuno assays using specific antibodies. The limit of quantification is 3-6 mg sesame seed protein/kg (ppm).
Sesame seed proteins can also be detected in food samples using rapid methods, based on test strips, which are soaked in an extract of the food or in swab sample extracts. Such test are only qualitative, i.e. the result is given either as sesame seed protein is present (positive) or sesame seed protein is not present (not detected) in the food extract. Positive results need sometimes to be confirmed with quantitative method. It is very important that qualitative test kites don´t give false negative results.
Sesame seeds can also be identified with DNA methods. Positive results in DNA analysis indicate the presence of sesame seeds in a sample.
Allergic reactions / Doses
Four cases have been reported to the Swedish National Food Administration where sesame seeds were causing allergic reactions. Two cases dealt with rice cakes contaminated during production, another case was caused by a pasta sauce with undeclared sesame seeds. Fish covered with a coating containing sesame seeds which was served at school lunch caused a severe reaction in a boy.
The levels of sesame seed proteins and the doses causing reactions have not been quantified.
Provocation studies of allergic individuals have shown that allergic reactions can be elicited by 30 mg sesame seeds and a few ml of sesame oil.