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Alertox for tree nuts: hazelnut


Tree nut allergy is one of the most powerful and frequent food allergies, in particular, it affects 1% of the population being more frequent in children. Reactions to nuts are severe, especially the first time that the consumer eats nuts without knowing about their allergy, (occurring) having breathing and cardiovascular problems.

Allergens involved in nut allergies belong to what’s known as plant defence related proteins (vicilins, legumins, albumins), which means that if one person is allergic to a specific kind of tree nut, they could probably be allergic to others, even though they come from very different plants. This is why all nuts are included in the same risk group.


Peanuts are a very common allergen, but don’t belong to the group of nuts, since they are a legume as lentils or beans.

Nuts mustn’t be mistaken with dried fruits like raisins, figs and plums, since their edible part is the pulp and not the seed.

The Food and Drug Administration recognizes coconut as a tree nut. It isn’t restricted in the diet for nut allergy , though some people have often reacted.

Tree nuts include, but are not limited to, almonds, Brazil nuts, cashews, chestnuts, filberts/hazelnuts, macadamia nuts, pecans, pistachios, pine nuts, and walnuts. The allergy to each nut has a different prevalence between countries. The hazelnut is the tree nut that causes more allergic reactions in Europe.

Hazelnut is the fruit of the hazel tree and its main allergen is the protein Cor a 1. When the body detects this protein in the food and recognizes it as strange, the immune system overreacts producing antibodies. Antibodies release a chemical called histamine, which causes the symptoms of the intoxication.

  • Skin: rashes and hives, eczemas, facial redness and swelling.
  • Digestive system: stomach ache, vomiting and diarrhea.
  • Respiratory system: runny nose, blocked nose, asthma attack, wheezing and cough.
  • Cardiovascular system: dizziness and drops in blood pressure.

Reactions are normally strong, immediate and can trigger an anaphylactic shock which can be life threatening.

What are some unexpected places where Hazelnuts can be an ingredient?

According to UE labeling and Codex Alimentarius, all products and foodstuff containing tree nuts must be labeled. However, it’s not unusual to find hazelnut as an ingredient or due to cross contamination on the machinery during the production process. The only treatment for tree nuts allergy, as occurs with other allergies, consists of a total avoidance of these products.

  • Pasta and baked products
  • Candies
  • Ice-creams
  • Asian, African and other cuisines
  • Sauces (pesto, chili sauce, barbeque, mole sauce…)
  • Liqueurs
  • Marzipan


Tree nuts can be found in your dog food or bird feed, including your pet saliva. Also in the food for hamsters and in its bed of straw, feed for livestock and some cosmetic products.

What can companies or laboratories do to control the presence of hazelnuts?

There are two products specialized in the detection of hazelnut allergens. The first of them is presented in an immunocromatic strip format, which permit any business to know the presence of the allergen on surfaces or ingredients; it is Alertox Stick Hazelnuts  (KT-6129). On the other side, Alertox ELISA Hazelnuts (KT-5907) is an ELISA test which can obtain quantitative data of the allergen.

Both tests are necessary to maintain the quality levels into the company, controlling the absence of the hazelnut allergen. In the same way, it is important that the company could work with a laboratory which offers a certified analysis service of allergens. This means analyses certified with the ISO 17025, the only test that can validate the results.

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