Over the past 25 years, food allergies have been recognized worldwide as an important public health issue. Specific avoidance diets remain the primary approach to the prevention of reactions among consumers with food allergies. The simple advice, for those who are allergic to peanuts or milk, for example, is just to avoid those foods or any ingredients derived from those foods. For packaged foods, ingredient statements on food labels are the key source of information for allergic consumers wishing to avoid specific foods.
Consumers with food allergies and their caregivers are likely the most diligent label readers in the marketplace, as their health and safety depend upon careful selection of food products. But, in reality, the seemingly simple advice to avoid allergenic ingredients can become quite challenging. Consumers with milk allergies must learn that casein and whey are terms that signify the presence of milk, that gluten and semolina mean wheat, and that tahina means sesame seeds, among many more examples.
General Labeling Regulations
Historically, many countries have stipulated general food labeling laws and regulations that served to protect food-allergic consumers to some degree. These general food labeling laws and regulations required that the ingredients intentionally used in the formulations of the foods should be declared on an ingredient list on the package label; however, these general food labeling provisions did not fully protect food-allergic consumers for a variety of reasons.
First, many exemptions and exceptions existed. Declaration of the sources of some ingredients was not required. Ingredients were often declared by using their common and usual names, which meant using technical terms (e.g., casein) that did not directly reveal the true source. Thus food-allergic consumers found that allergens were often “hidden” in packaged food products. Furthermore, they had to learn to identify technical ingredient terms such as “casein” that indicated the presence of specific allergenic foods. Vague terms such as “hydrolyzed vegetable protein” were allowed in some countries and these did not reveal the source. Some countries had regulations that did not require the labeling of ingredients in complex formulations when the ingredient comprised less than 25% of the finished food; other countries exempted labeling of minor ingredients comprising less than 2% of the formulation.
The History of Food Allergen Labeling Regulations
The plight of food-allergic consumers and their struggles in implementing specific food-avoidance diets were first recognized in the 1990s. Several Nordic countries developed a working paper on food allergens and labeling in 1993 that was submitted to the Codex Alimentarius Commission (CAC), an organization that oversees the Food and Agricultural Organization (FAO) and the World Health Organization (WHO) to develop food standards and guidance that could be recognized and harmonized worldwide. CAC does not promulgate regulations but does provide guidance that individual countries and regulatory jurisdictions may consider and use as they develop regulations.
In response to the Nordic working papers on food allergens, a FAO Technical Consultation was formed in 1995, which led to the development of the first global list of priority allergenic foods (see Table 1). This list was formally adopted by CAC in 1999. The CAC list of priority allergenic foods served as guidance to all countries, but individual countries had the option to adopt this list or to modify the list as they might choose.
Several comments are appropriate regarding the approaches used by the 1995 expert panel to develop this priority list of allergenic foods. In 1995, the level of published information regarding the comparative prevalence of allergies to specific foods was rather limited and primarily consisted of information on pediatric populations of allergic individuals. These data were primarily from referral centers, which see more allergic patients so extrapolation of the prevalence of pediatric allergies to the overall population may have been slightly biased. Data were lacking on adults with food allergies and on the prevalence of specific food allergies in the general population.
Accordingly, the panel relied, in part, on expert judgment to develop the 1999 priority allergen list. The main criterion for inclusion was comparative prevalence, although the differential severity of certain allergenic foods was also recognized. On this basis, milk, eggs, fish, crustacean shellfish, peanuts, soybeans, tree nuts, and cereal grain sources of gluten were considered the priority allergenic foods. The FAO group also considered celiac disease, intolerances, and sensitivity reactions, in addition to food allergies. Thus, gluten was included because of its association with celiac disease, and sulfites were included because of the documented severity of sulfite-induced asthma, even though these illnesses are not true food allergies.
Subsequently, an International Life Sciences Institute (ILSI) Europe Task Force on Food Allergy took a more in-depth look at foods that merited placement on the priority allergenic foods list (Allergy. 1998;53:3-21). The criteria used by this group included clinical evidence of an allergic reaction through double-blind, placebo-controlled food challenge (DBPCFC) and published evidence of severe and/or fatal anaphylactic reactions. Data on prevalence were considered insufficient. This task force determined that the priority list should include milk, eggs, fish, crustacean shellfish, peanuts, soy, tree nuts, wheat, and sesame seeds. Several subsequent groups within ILSI Europe have continued to develop criteria for the selection of allergenic foods of public health significance (Regul Toxicol Pharmacol. 2008;51:42-52; 2011;60:281-289). The criteria have been expanded to include prevalence, severity, and potency.
The adoption by CAC of the priority list of allergenic foods prompted numerous countries to develop their own regulatory lists for the labeling of priority allergenic foods. The eight foods or food groups from that 1999 CAC list were represented on the vast majority of the priority food allergen lists recognized by specific countries; this group of allergenic foods began to be referred to as the “Big 8.”
Several countries, however, decided to include additional foods on their priority allergen lists. As a result, the regulatory framework for the labeling of allergenic foods differs from country to country. The basis for inclusion of additional foods on the priority lists for specific countries has not been clearly delineated but is based, in part, on regional differences in the prevalence, severity, and potency of specific allergenic foods. The role of scientific criteria in these judgments appears to be secondary in many cases. While the World Trade Organization Agreement on the Application of Sanitary and Phytosanitary Measures recognizes the 1999 CAC list, the existence of different priority lists in various parts of the world can lead to trade disputes and consumer confusion.
Global Differences in Lists of Priority Allergenic Foods
Regional differences appear to exist in the prevalence of food allergies around the world. For example, buckwheat allergy is much more common in Southeast Asian countries where soba noodles are frequently consumed but is a rare form of food allergy in North America and most other parts of the world. The identity of the most common allergenic foods differs among countries/regulatory jurisdictions (such as EU and Australia/New Zealand) in part as a result of these regional differences.
In the U.S., the priority list of allergenic foods was established by action of the United States Congress when it passed the Food Allergen Labeling and Consumer Protection Act (FALCPA) in 2004. FALCPA established a list of priority allergenic foods that was quite similar to the 1999 CAC list (see Table 2). The only exception was that FALCPA specifically identified wheat as a cause of food allergies and does not recognize other grain sources of gluten. More recently, the U.S. Congress passed a bill that has prompted the FDA to include sesame seeds on the list of the priority allergenic foods, effective this year.
The first priority list of allergenic foods for the EU was established by EC Directive 2003/89 but has been subsequently expanded by more recent directives (see Table 2). The EU list includes sesame seeds, mustard, celery, molluscan shellfish, and lupine in addition to the Big 8. The European Commission relied upon the expert opinion of the European Food Safety Authority (EFSA) Scientific Panel on Dietetic Products, Nutrition, and Allergies for the addition of molluscan shellfish and lupine to the EU priority allergen list (EFSA J. 2006;327:1-25; 2005;302:1-11).
The decision on lupine appeared to be based upon the recognition that some peanut-allergic individuals will experience allergic reactions to ingested lupine. Several non-EU countries have adopted the EU priority list of allergenic foods (Ukraine, United Kingdom, Iceland, Switzerland, Turkey, and Russia).
In Canada, the original priority allergen list included the Big 8 list with the addition of molluscan shellfish and sesame seeds. More recently, Canada has added mustard to its list. In Australia and New Zealand, the priority list has gone through a couple of iterations but now includes the Big 8 plus sesame seeds, molluscan shellfish, lupine, bee pollen, propolis, and royal jelly (see Table 2).
Japan has a rather unique approach to its priority list, with a short mandatory labeling list and a longer recommended labeling list. The mandatory priority list in Japan comprises wheat, milk, eggs, peanuts, buckwheat, and crustacean shellfish (see Table 2). Crab and shrimp are identified as the only crustacean shellfish of concern. Japan and Korea are the only countries that list buckwheat on their priority allergen lists. Buckwheat is known to cause frequent and occasionally severe allergies in Japan (Adv Food Nutr Res. 2011;62:139-171; Allergy Clin Immunol Int. 2003;15:214-217).
The recommended priority list in Japan is extensive and includes several molluscan shellfish (abalone, squid), several fish (mackerel, salmon, and salmon roe), several fruits (orange, kiwi, peach, apple, banana), one tree nut (walnut), several meats (pork, chicken, beef), soybeans, matsutake mushrooms, yams, and gelatin. The basis for the Japanese priority list was a survey of allergy clinics in Japan in which the causative foods in more than 1,500 cases of food allergy were compared (Allergy Clin Immunol Int. 2003;15:214-217).
The 1999 CAC priority list includes several food groups: tree nuts, fish, and crustacean shellfish. In most countries, fish refers to all species of finfish. The exception is Japan, where only mackerel and salmon are included on the recommended priority list for allergenic foods. Similarly, crustacean shellfish refers to all species of shrimp, crab, and lobster in most countries; in Japan, only crab and shrimp are included on the mandatory priority list for allergen labeling. In several countries including Canada, the labeling regulations refer only to shellfish and not specifically to crustacean shellfish or molluscan shellfish.
Greater differences occur among various countries as to which tree nuts are recognized as part of the group covered by allergen labeling regulations. In Europe, the tree nuts group includes walnuts, pecans, cashews, pistachios, almonds, hazelnuts, Brazil nuts, and macadamia nuts. In Canada, these same eight nuts are listed along with pine nuts; however, the U.S. Congress did not identify specific tree nuts that required mandatory labeling under the provisions of FALCPA. Subsequently, FDA issued a draft guidance document in October 2006 that included a very long list of 19 tree nuts that would need to be specifically included on U.S. food labels. Unfortunately, this list includes several foods that are not tree nuts by botanical definition (coconut and litchi).
Recent FAO/WHO Recommendations
In 2020, on request from the Codex Committee on Food Labeling (CCFL), an ad hoc Joint FAO/WHO Expert Consultation on Risk Assessment of Food Allergens was established. In the first of a series of meetings held in late 2020 and early 2021, the consultation developed recommendations relating to the priority list of allergenic foods based on updated information. Considerably more scientific and clinical information was available than had been the case in the previous FAO consultation in 1995. The expert panel based their updated recommendations on the prevalence, potency (threshold dose considerations), and severity of allergic reactions to specific foods.
As a result of these deliberations, a new, revised list of priority allergenic foods was established (see Table 3) that included eight foods or food groups, as before; however, the experts recommended deletion of soybeans from the priority list along with the addition of sesame seeds. This recommendation has been forwarded to the CCFL for consideration and, if approved at that level, will be forwarded to the CAC to create the basis for revised worldwide guidance on allergenic food labeling.
Soybeans were removed from the priority list of allergenic foods based on the low prevalence of soybean allergy, especially among older children and adults, the decline in soybean allergy in infancy, possibly owing to a decreased use of soy-based infant formula, the lower potency of soy protein for elicitation of allergic reactions, and an observed low degree of severity of allergic reactions to soybean reported across all Codex regions. Sesame seed was added to the priority list because of moderate levels (compared with other priority allergenic foods) of prevalence, potency, and severity of allergic reactions. Also, many individual countries had already added sesame seeds to their priority allergenic food lists based on their own assessment of risk factors for sesame seed allergy.
In the recommendation from the expert consultation, the category of tree nuts was restricted to those tree nuts for which evidence of prevalence, potency, and/or severity merited their inclusion. The tree nut list included hazelnut, walnut, pecan, cashew, pistachio, and almond.
The expert consultation also pointed out that regional differences could exist with respect to prevalence, potency, and severity that could merit the inclusion of additional foods on the priority list of allergenic foods in certain countries. Examples might include buckwheat in Japan and Korea and celery tuber in the EU.
Ingredients Derived from Priority Allergenic Foods
The original 1995 list of priority allergenic foods also referred to “products of” those foods. Many food ingredients are derived from the priority allergenic foods that were shown to have medium to high potency and a higher proportion of reported anaphylaxis in more than three Codex regions.
Examples of such ingredients contain large amounts of protein from the allergenic source, while other ingredients contain very low levels of residual protein from the source food. Several countries have exempted certain ingredients from their source labeling provisions. In the U.S., all highly refined oils, including those made from peanuts and soybeans, are exempt. In the EU, highly refined soybean oil is exempt but highly refined peanut oil is not. The EU has also exempted certain other derivatives from source allergen labeling, including wheat starch hydrolysates and fish gelatin for vitamin encapsulation; however, until now, no global consensus has existed to make decisions about source labeling exemptions for certain food ingredients derived from priority allergenic foods.
The ad hoc Joint FAO/WHO Expert Consultation on Risk Assessment of Food Allergens took up the topic of assessment of the allergenicity of derivatives from priority allergenic foods at its most recent meeting in November 2022. The recommendations of that consultation are not yet public, but recommendations for a framework by which labeling exemption considerations could be evaluated were made for further consideration by CCFL to create a basis for global scientific consensus on source labeling exemption decisions.
The authors are with the Food Allergy Research and Resource Program in the Department of Food Science and Technology at the University of Nebraska-Lincoln. Reach Dr. Taylor at [email protected] and Dr. Baumert at [email protected].
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