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Allergy policies for nut-free commercial flights and nut-free childcare settings are not a rare occurrence nowadays—the reason is a rise in food allergies. Nuts are the most potent allergenic foods in terms of the amount that is required to elicit an allergic reaction and the severity of those reactions.

In food safety, food allergens stand out among other compounds that are tested in our foods because of their potential to cause immediate life-threatening reactions mediated via immunoglobulin E binding. In this blog, we will address common questions surrounding food allergens, which have been drawing global attention from authorities and food manufacturers alike.

What are food allergens?

Food allergens are proteins found in certain foods that trigger an abnormal immune response. They are naturally occurring compounds and are not chemical residues.

The major allergenic foods that are regulated by authorities are largely aligned across the global landscape, as shown in the overview lists below. These allergens must be clearly identified on food labels to alert consumers with food allergies.

China (GB7718-XXXX draft):

• Grains and grain products containing gluten substances, such as wheat, rye, barley, oat, spelt or

their crossbreeding products

• Crustacean animals and products
• Fish and fish products
• Eggs and egg products
• Peanuts and peanut products
• Soybeans and soybean products
• Milk and dairy products (including lactose)
• Nuts and nut products

Europe (EU FIC: N°1169/2011)

• Cereals containing gluten, such as wheat, rye, barley and oats
• Crustaceans, such as shrimp, crab and lobster
• Eggs
• Fish
• Peanuts
• Soybeans
• Milk (including lactose)
• Nuts, such as almonds, hazelnuts, walnuts and cashews
• Celery
• Mustard
• Sesame
• Sulphur dioxide and sulphites (at concentrations of more than 10 mg/kg or 10 mg/L)
• Lupin
• Molluscs, such as clams, mussels and oysters

United States (FALCPA):

• Milk
• Eggs
• Fish
• Crustacean shellfish
• Tree nuts
• Peanuts
• Wheat
• Soybeans
• Sesame (effective January 1, 2023)

Singapore (Singapore Food Agency [SFA] and Singapore Food Regulations [SFR])

• Cereals containing gluten (includes wheat, rye, barley, oats, spelt or their hybridized strains and their products)
• Crustacean and crustacean products
• Eggs and egg products
• Fish and fish products
• Peanuts and soybeans and their products
• Milk and milk products (including lactose)
• Tree nuts and nut products
• Sulphites in concentrates of 10mg/kg or more

The EU has the most extensive list compared to the other countries listed above, since it includes additional allergens like celery, mustard, and lupin that are not listed in the US, Singapore or China regulations.

What are the associated risks for people with food allergies?

For food allergy sufferers, the battle extends beyond physical health. Social situations can become loaded with anxiety, leaving those with allergies feeling isolated and misunderstood. Food allergy is a risk factor for depression and severe psychological distress, not only for the people afflicted, but for the parents of children with allergies as well.

Access to specialized healthcare services, including allergists and dietitians, may be limited in underserved areas. This lack of support can leave people struggling even more to manage the condition.

As allergen-free processed foods usually come at a higher price point, food allergies impose a financial burden on affected families. In addition, the necessary medications can be overwhelming for those already coping with the daily challenges of food allergies.

Why are allergies on the rise?

We know food allergies are on the rise, but we don’t know exactly why. About 10% of adults and 2% of children are affected by food allergies. The numbers for infants are higher in Australia, with about 10% of one-year-olds affected, and have prompted more local research into contributing factors. These factors include raised hygiene standards and increased consumption of processed foods and additives. Pollution and other environmental factors may also play a role. It has already been shown that air pollution has been linked to an increased allergic sensitization.

The route of exposure also plays an important role in developing a food allergy. If the body is first and repeatedly introduced to foods through the skin, as opposed to through the mouth and GI tract, it may increase the likelihood of sensitization to that food. That explains why children with eczema are more likely to develop food allergies.

How can food allergens cause cross-contamination?

Cross-contamination can happen when a small amount of a food containing allergens accidentally gets into another food through the manufacturing or food preparation process. Shared equipment and insufficient cleaning between production batches are other contributing factors. These mechanisms of cross-contamination are why food manufacturers are especially alert when it comes to allergen management.

Contamination can also occur outside of manufacturing facilities through contact with cooking utensils and other surfaces in restaurants or kitchens. Transport can also play a role when bags of commodities are placed next to each other during shipment.

Can allergens be destroyed?

The answer is, it depends on the allergen. Not all allergens can be destroyed with cooking or other processing methods, not even with high heat. But some allergens are more heat-susceptible than others. For example, when baked, milk and eggs can contain lower levels of allergens than the initial products. This is not the case with peanuts, however.

Is food allergy equal to food intolerance?

The main difference is the severity of symptoms and the organ systems affected. A true food allergy is mediated by the immune system and can be severe or life-threatening, resulting in symptoms in different organs. In contrast, a food intolerance often only affects the digestive system and causes less serious symptoms, like diarrhea or vomiting.

Will food allergies go away?

There is no definitive answer. Allergies to milk, eggs, wheat and soy can lessen over time, and some people grow out of allergies altogether. However, those who suffer from allergies to peanuts, tree nuts, fish and shellfish tend to be affected for a long time.

Which technologies are used for allergen testing?

The two main technologies to detect allergens in food are the enzyme-linked immunosorbent assay (ELISA) and mass spectrometry (MS).

ELISA is a binding assay, commercially available as consumables like well-plates and reagents that contain specific enzyme-labeled antibodies. Allergens can be detected by a colorimetric reaction after binding of the allergen-protein with the antibody.

MS coupled with liquid chromatography measures peptides that are derived from allergenic proteins in food samples.

An advantage of MS for allergen testing is the fact that multiple allergens can be measured within the same analysis time. ELISA tests are limited to one type of allergen, so testing for multiple allergens requires the purchase of different kits. MS is also robust against the changes that can occur in sample treatment and sample preparation. As proteins are digested prior to analysis, the folding stage of a protein that could be altered via processing of the food might not be recognized by ELISA. MS can detect proteins independently of their ability to be recognized by specific immunoglobulin E and in this way can help in the elucidation of the allergen profile of a food. Cross-reactivity of carbohydrates on antibody-binding sites is sometimes observed with ELISA and is an issue that MS users do not have to worry about. With regard to sensitivity, both methods are comparable. An article in Nature summarizes: ”In studies comparing both methods, the sensitivity and accuracy of MS have been shown to be either similar to ELISA or substantially greater depending on the ELISA, allergen and degree of food processing, except in the case of pasta spiked with egg prior to cooking.”

Less known and less widely used tests are the lateral flow immunoassay (LFIA), which is a strip test that is easy to use but limited to one allergen, and the multiplex allergen microarray-based immunoassay, which allows for the detection of several allergens but has not been widely used in the food testing market today.

Is there a cure for food allergies?

Living with food allergies can feel like walking through a minefield, with each meal holding the potential for danger. Anaphylaxis, a severe allergic reaction, poses the most significant threat, requiring immediate treatment with epinephrine to prevent a potentially fatal outcome.

So far, there is no cure for food allergies, leaving strict avoidance of allergenic foods as the primary defence strategy. But a wave of hope has emerged from a recent announcement. In February 2024, the U.S. Food and Drug Administration approved Xolair for immunoglobulin E-mediated food allergies to reduce allergic reactions, including the risk of anaphylaxis. This could pose a significant enhancement to the quality of life for many people affected by food allergies.

Immunological research, product testing, medication and compassion

The effects of allergenic proteins in our foods are far-reaching. As a result, ensuring the safety of people with food allergies is a major task that can only be managed as a collaborative effort by scientists, producers and governments. Understanding the underlying mechanism in immune responses and using technology to monitor allergen occurrence are the two major routes to handling the threats emerging from food allergens.

For the food industry, turning to very sensitive testing methods like MS for food allergens has proven to help mitigate risks in production and elucidate allergenic potential in product development.

On a broader societal level, fostering an understanding for those living with food allergies can build a more inclusive and compassionate society where people with food allergies feel accepted until medications are widely available to manage the condition.

Other sources:

https://www.fda.gov/news-events/press-announcements/fda-approves-first-medication-help-reduce-allergic-reactions-multiple-foods-after-accidental

Food Allergy & Anaphylaxis | Prevention | Why Are Food Allergies On the Rise (foodallergyawareness.org)

Mythbuster: Cooking a food at high temperature will kill the protein and I won’t be allergic to it. – Food Allergy Canada

Food Allergies | Causes, Symptoms & Treatment | ACAAI Public Website