Hazelnut allergens, food processing effects and detection methods
What it found
Hazelnuts contain multiple proteins that trigger allergic reactions in people, and some survive cooking.
Lab tests show certain processing methods lower the ability of these proteins to cause a reaction.
What they found
Studies in people
Allergic reactions in people
People allergic to hazelnuts can experience skin rashes, breathing problems, stomach issues, or life-threatening shock after eating them. Children are more likely to have this allergy than adults, with rates between 0.5% and 1% in Europe.
Cross-reactions with other foods
People allergic to hazelnuts often react to almonds, walnuts, pistachios, and peanuts because the proteins look similar. Those with pollen allergies to birch, hazel, or alder trees are also more likely to react to hazelnuts.
Studies in people and animals
Heat treatment effects
In lab tests, heating hazelnuts at 140°C for 40 minutes lowered their ability to trigger an immune response, but 29% of allergic patients still reacted. Autoclaving at 138°C for 15 to 30 minutes reduced the reactivity of several hazelnut proteins.
High pressure processing
Lab tests showed that treating hazelnuts with very high pressure changed how easily the proteins dissolved. However, it did not change how well those proteins bound to allergy antibodies from people.
Other findings
Detecting hazelnut traces
Food makers use antibody tests to find hazelnut proteins down to 0.3 mg/kg. DNA-based tests can spot hazelnut genetic material at levels as low as 1 mg/kg in various foods like chocolate and baked goods.
What the authors conclude
- They state that understanding the specific proteins in hazelnuts is essential for better diagnosis and management of allergies.
- Their review highlights that food processing can lower but not remove the allergenic potential of hazelnuts.
- They advise combining advanced detection tools with strict ingredient labeling to protect consumers who are allergic.
How it was done
Hazelnut allergies are common and can cause severe reactions, so researchers wanted to gather current knowledge on how these allergens behave during food production and how they can be detected.
The authors gathered and examined published research on hazelnut allergens. They looked at studies involving people with allergies, lab tests on proteins, and methods used by the food industry to detect hazelnut traces.
What it can’t tell you
- Because this work gathers existing research rather than running a new controlled trial, it cannot prove that any single processing method prevents allergic reactions in all people.
- Sensitization rates measured in blood do not always mean a person will have symptoms when eating hazelnuts.
Who paid
- Funding
- Funded by National Key Research and Development Program of China; National Natural Science Foundation of China; Fundamental Research Funds for the Central Universities (from the PubMed record).
- Conflicts
- The authors have confirmed that there are no conflicts of interest. None of the authors has interests in promoting a biosensor or something else commercial.
- Authors work at
- Southeast University, China; McGill University, Canada
The paper
- Title
- Update on hazelnut allergy: Allergen characterization, epidemiology, food processing technique and detecting strategy
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Camus-Ela M, Wang Y, Rennie GH, Raghavan V, Wang J (2025). Update on hazelnut allergy: Allergen characterization, epidemiology, food processing technique and detecting strategy. Comprehensive reviews in food science and food safety. doi:10.1111/1541-4337.70098Free full textPubMed 39898897DOI
Summary written 1 Oct 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error