Which countries regulate sesame as food allergen?
Currently Europe, Canada and Australia/New Zealand require the labelling of sesame as food allergen. Japan has added sesame in 2013 to the list of 20 allergens which are recommended to be labelled (but are not mandatory at this point).
In Europe, lawmakers required sesame labelling already in 2003, jointly with 11 other substances causing food allergies or intolerances. In 2014, the European Food Safety Authority (EFSA) updated its opinion of allergenic foods and food ingredients for labelling purposes. For sesame, it stated that the highest prevalence in Europe is 1.5 % in France among 5-17 year-old individuals. While information about documented severe reaction was scarce, a questionnaire suggested that sesame was responsible for severe reactions.
What are the reasons of FDA to consider now adding sesame to the list of allergens requiring labelling?
In a statement of departing FDA Commissioner Scott Gottlieb on Oct 29, 2018, he mentions that “Unfortunately, we’re beginning to see evidence that sesame allergies may be a growing concern in the U.S. A handful of studies, for example, suggest that the prevalence of sesame allergies in the U.S. is more than 0.1 percent, on par with allergies to soy and fish. Because sesame is not recognized as a major allergen, right now it’s not required to be declared as an allergen on food labels. In fact, it may not always be specifically listed in the ingredient statement. Products with “natural flavors” or “spices” listed on their label may contain small amounts of sesame. And people allergic to sesame might eat food labeled as containing “tahini” without knowing that tahini is a paste made from sesame seeds. Fear of not knowing whether a food contains sesame may lead some people to unnecessarily limit their diets to avoid possible exposure.”
As mentioned by Harriet Moonesinghe and co-authors in their 2015 review, very little data about the true prevalence of what the authors consider “novel” food allergens (celery, lupin, mustard and sesame) are available. So, if prevalence of sesame allergy is only 0.1% or higher in the US is unknown. The US FDA also recognized this and is therefore issued a request for information.
How many sesame allergens are there?
For sesame, there are seven characterized proteins which can trigger the allergy reaction. These fall into three protein families: two prolamins (Ses i1 and i2), two oleosins (Ses i4 and i4) and three cupins (Ses i3, i6 and i7).
Are sesame allergens heat stable?
This information is essential for food manufacturers using sesame in baked products. The answer is: yes. The major Sesame allergen, Ses i1, is stable up to 90°C. Ses i1 is also highly resistant to digestion in the gastrointestinal tract which is common to many food allergens.
VITAL reference dose and enforcement levels for sesame
For sesame, the VITAL reference dose for sesame protein is set at 0.2 mg, with an ED05. In Germany, the VITAL reference dose has been adopted and the action level is set to >10mg/kg, meaning that if the competent authorities find more than 10 mg/kg (or 10 ppm), they will take action.
In the neighbouring countries, The Netherlands propose a significantly lower reference dose of 0.1 mg sesame protein, while Belgium, the other neighbouring country set a substantially higher reference dose of 0.4 mg sesame protein. In other words, if you live in Belgium, 400 g of a dish can contain a maximum of 1 mg/kg sesame protein, while in Holland, the same dish could only contain 0.25 mg/kg sesame protein to reach the reference dose in the respective country. However, analytically, 0.25 mg/kg sesame protein may not be detectable by most commercial assays.
Detection of sesame
Commercial ELISA (Enzyme-Linked Immuno-Sorbent Assay) systems for sesame are available from many vendors. Equally, DNA-based systems (PCR – Polymerase Chain Reaction) are also described in the literature and available commercially. More recently, mass spectrometry methods for detection of sesame have been published, too.
Prevalence of Sensitization and Prevalence of Sesame Allergy in different Countries
According to the EFSA report (2014), sesame allergy is comparably rare (averaged about 0.1% compared to 1% for peanuts and tree nuts – this percentage varies from region to region). However, children sensitized to sesame had a high prevalence of sensitization to peanuts, hazelnut, walnut, almond, and egg. Both, cross-sensitivity and clinical cross-reactivity, were observed between sesame, peanut and tree nuts
The prevalence of sesame allergy is subject to significant geographical variation. In the Middle East, popular dishes like tahini and halva contain sesame, and it was assumed that, based on the higher consumption rates of sesame in those regions, the prevalence of sesame allergy was high. Sesame was already termed “peanut of the Middle East”. The assumed higher prevalence in the Middle East was supported by Israeli studies with small groups. However, those studies were not population-based. A higher prevalence is reported from Australia (0.8%) and UK (0.4%).
As mentioned previously, there are still very little data available to determine the true prevalence of “novel” food allergens like celery, lupin, mustard and sesame. Harriet Moonesinghe and co-authors come in their 2015 review to the conclusion: “There is surprisingly little data available on the prevalence of these novel food allergens despite the fact that they appear in the top 14 food allergens listed by the EU.”
It remains to be seen how much reliable evidence can be gathered through the FDA call for information to support the assumption that the prevalence of sesame allergy in the USA is higher than 0.1%. Given that the prevalence of sesame is likely significantly lower than those for peanut and tree nuts, will sesame be the 9th mandated allergen in the US?
If you are interested in sesame or other allergens, a significant amount of information can be found in the open access edition of the Journal of AOAC on Food Allergens which was published earlier this year (2018).
