Food Allergens: the FDA Perspective

Kenneth J. Falci and Katherine Vierk Center for Food Safety and Applied Nutrition U.S. Food and Drug Administration

Food allergies affect an estimated 6% of children younger than 3 years and 1.5% of adults in the United States1. A food allergy is an IgE-mediated immunologic reaction to an ingested food and may result in a variety of symptoms involving the skin, gastrointestinal tract, respiratory tract and/or vascular system. Currently there is no cure for food allergy; sensitive individuals must manage their food allergy through avoidance of foods containing the allergen and vigilant reading of food product labels. Any food protein is capable of causing an allergic reaction, however, only eight foods or food groups account for more than 90% of all IgE-mediated food allergies2. These eight most common foods are peanuts, soybeans, milk, egg, fish, crustacean shellfish, wheat, and tree nuts (e.g., hazelnuts, almonds, walnuts, pecans, pine nuts). Low amounts of the proteins in these foods may elicit an allergic response and reactions may vary from mild to life threatening, depending on a person’s particular sensitivity3. Bock et al. predict that there are approximately 29,000 anaphylactic episodes resulting in about 150 deaths due to food allergy in the United States each year4. The United States Food and Drug Administration (FDA) is actively involved in efforts focused on defining and preventing illnesses and deaths from food allergy.


In the U.S., the Federal Food, Drug, and Cosmetic Act (FFDCA) requires, in virtually all cases, a complete listing of all ingredients of a food on the food label. One exemption, FFDCA 403(i)(2), allows for the collective declaration of spices, flavours and colours. However, food labels with collectively named spices, flavours and colours may not clearly inform individuals who wish to or need to avoid allergenic substances. It is therefore recommended by the FDA that food manufacturers voluntarily declare allergenic ingredients in a spice, flavour or colour5. In 1996, FDA issued a notice to the food industry to both alert them and request their assistance in addressing the potential public health problem in sensitive individuals associated with undeclared allergens in food6. The voluntary declaration could be accomplished by declaring the allergenic ingredient in the ingredient list parenthetically following the name of the spice, flavour or colour, or as a separate listing immediately below the list of ingredients on the food label.

Secondly, 21 CFR 101.100(a)(3) allows incidental additives such as processing aids to be exempt from ingredient labelling requirements, when they

  1. are present in a food at insignificant levels and
  2. do not have any technical or functional effect in the finished food.

To qualify for this exemption, the incidental additive must meet both of these requirements. In this case, each food manufacturing firm must make an assessment of the food ingredients that may be introduced during processing and thus into the final product to determine if the food substance should be present on the label. Additionally, FDA has stated its policy that food allergens do not meet the requirements for the incidental additives exemption because any level of an allergenic substance in a food is not considered insignificant. This policy is based on evidence that suggests that in some individuals, ingestion of very small amounts of the allergen can cause serious allergic reactions3. Therefore any amount of an allergenic substance that may cause an allergic reaction is not insignificant and does not meet the requirements of 21 CFR 101.100(a)(3)6. When these labelling errors are found by consumers, the food industry or FDA, the food label is usually corrected and recall of a company’s products may occur7.


While it is understood that an added ingredient must be declared in the ingredient statement of a food product, inadvertent introduction of allergens can occur during the manufacturing process. Between 1999 and 2002, there were 319 recall actions of food products containing undeclared allergens (about 25% of total food product actions between 1999-2002). Although the number of recall actions remained steady at about 68 recall actions through 2001, the number increased to 116 recall actions in 2002. Many reasons for this marked increase are possible such as more awareness about allergens in the public and industry, increased number of inspections by state agencies and FDA, development of ELISA tests for allergens, or a true increase in the number of food products with undeclared allergens. FDA does not have the authority to order food recalls; food product recalls are generally done voluntarily by firms with FDA’s help to monitor and assist in the recall effort.

Three principle factors may contribute to the presence of undeclared allergens in recalled products. One of these factors is a food product label with incorrect lists of ingredients. This occurred in 60% of the recall actions in 19998. Examples of incorrect ingredient statements include not declaring sub-ingredients of an ingredient, changing product formulations and incorrectly translating ingredient statements on foreign food products to English. A second factor is manufacturer or supplier errors (18% of recall actions in 1999)8. Employees in a manufacturing company may make errors on the processing or packaging lines that lead to the presence of undeclared allergens. Examples include incorrect packaging for a product or using rework that contains allergenic ingredients in the manufacture of non-allergen containing products. Additionally, suppliers may inadvertently supply an incorrect ingredient or change an ingredient formulation without notifying the manufacturer to update the food label. A third factor may occur when leftover product that contains allergens comes into contact with the next non-allergen product manufactured on the shared line and from equipment that has not been sufficiently cleaned. This type of cross-contact from equipment during manufacturing accounted for 18% of the recalls in 19998. Methods for reducing the possibility of cross-contact would be to run allergenic products on a separate line or to sequence allergenic products after non-allergen containing products.

FDA, state agencies, industry, and consumers all play a part in discovering food products containing undeclared allergens (Figure 1). In 1999, consumers identified 50% of all products recalled as containing undeclared allergens. While some consumers discover the allergen before consuming the product (possibly by direct observation of the allergen in the product), other consumers suspect the presence of an undeclared allergen after consuming the product and having an allergic reaction. Through company inspections in 1999, FDA and state health agencies discovered 31% and 10% of the recalled products respectfully and industry discovered 6%. Since 1999, FDA has continued its outreach efforts to both industry and consumers in order to educate them about allergens and inadvertent cross-contact of other non-allergenic products with allergens. In 2002, industry increased their detection of undeclared allergens in products before these products reached the marketplace (from 6% to 25% in 2002). In contrast, discovery of undeclared allergens by consumers decreased by 46% from 1999 to 2002. During this period, FDA continued to recall products for undeclared allergens through inspections at the same level, while state health agencies saw a 41% increase.


Exposure to small amounts of allergenic protein can elicit an allergic response in individuals with IgE-mediated food allergies. A threshold dose is the lowest amount of the offending food that elicits an allergic response3. In its 1996 Notice to Manufacturers, FDA indicated that any amount of a substance that may cause an adverse reaction is not insignificant. While several clinical studies have shown that threshold doses of common allergenic foods are possible, determination of threshold doses for allergens remains a challenge. These challenges include the lack of standardized clinical challenge protocols, difficulty in obtaining an appropriate sample of food allergic individuals and lack of standardized challenge materials (e.g. ground peanut vs. peanut flour).

Another challenge for a manufacturer is the voluntary placement of advisory statements (“May contain” labelling) on Figure 1: Parties responsible for first identifying undeclared allergens, 1999 and 2002 recall actions food packaging labels. While the advisory statements are intended to notify consumers of possible allergenic ingredients, it is unclear if the allergen is or is not present in the product. There are a wide variety of advisory statements being used by manufacturers (e.g. “may contain milk”, “manufactured in a plant that also manufactures peanuts”, “may contain traces of other nuts”). FDA is gathering data on the extent of and reasons for use of advisory statements. The agency advises that use of advisory statements should not be used in lieu of good manufacturing practices.


Since 2000, the FDA’s Center for Food Safety and Applied Nutrition (CFSAN) has made several accomplishments with regard to food allergy. CFSAN has made it a top priority to continue outreach activities to increase food allergy awareness among industry and consumers. Outreach efforts have provided opportunities for FDA to communicate information on policies, labelling, and current activities and gather information and concerns from industry and consumers. In 2001 CFSAN issued two guides, the Compliance Policy Guide for labelling and preventing cross-contact of common allergens and an Inspection Guide for inspections of companies susceptible to allergen cross-contact (both available at In addition, training was given to all FDA inspectors in the U.S. in order for FDA to ask appropriately focused questions to companies producing foods with allergenic ingredients. This training allowed FDA to ask allergen questions in an informed manner during inspections in over 1500 companies in 2002. The information collected in the questionnaires used is currently being compiled and assessed.


It is the authors’ belief that allergic reactions to food will continue to be an FDA concern in the years to come because the consumer population directly at risk includes both children and adults. The authors expect that there will be increased research centred on threshold levels for the eight major food allergens and risk assessments of the health hazards associated with exposure to the predominant common food allergens. The authors also agree that addressing consumer protection in a meaningful way via retail food store and restaurant operations will also present a challenge that will require industry, consumer and regulatory scrutiny. Awareness of food allergens used at retail and at the restaurant level will have to be the first step. The challenge is difficult since there is a large annual turnover rate of staff in the restaurant industry.

In addition, both a new food allergen labelling rule for the food label and possibly a good manufacturing practices rule describing allergen control procedures to be used in food plants are possible future regulations. There will also be a need to measure the effectiveness of these regulations as agency thought moves toward establishing performance measures for new food allergen programmes. Finally, ELISA test kit evaluations for detection of peanut protein will be completed and this work will expand to other allergenic proteins derived from eggs, milk, hazelnuts, and soy. Legislative action regarding declaration of food allergens is also under discussion. However, the exact requirements Congress may require for food allergens remain unknown.

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  3. Taylor SL et al. Factors affecting the determination of threshold doses for allergenic foods: How much is too much?. J Allergy Clin Immunol 2002;109(1):24-30.
  4. Bock SA, Munoz-Furlong A, Sampson HA. Fatalities due to anaphylactic reactions in foods. J Allergy Clin Immunol 2001;107(1):191-3.
  5. Formanek Jr. R. Food Allergies: When Food Becomes the Enemy. FDA Consumer. July-August 2001.
  6. U.S. FDA. Notice to Manufacturers. June 10, 1996.
  7. Falci KJ, Gombas KL, Elliot EL. Food Allergen Awareness: An FDA Priority. Food Safety Magazine 2001;7(1):14-5, 43-4.
  8. Vierk KA, Falci KJ, Wolyniak C, Klontz KC. Recalls of foods containing undeclared allergens reported to the US Food and Drug Administration, fiscal year 1999. J Allergy Clin Immunol 2002;109(6):1022-6.

Dr. Kenneth J. Falci is the Director of the Office of Scientific Analysis and Support, Center for Food Safety and Applied Nutrition (CFSAN), US Food and Drug Administration. Specifically, his office oversees the development of economic impact analyses for food and cosmetic regulations, the conduct of consumer attitude studies, provides epidemiological reviews for microorganism risk assessment, acute health hazard evaluations, and estimates for the burden of foodborne illness. Dr. Falci has oversight responsibilities for the development of the CFSAN Adverse Events Reporting System (CAERS).

Katherine Vierk is currently an Epidemiologist in the Office of Scientific Analysis and Support, Center for Food Safety and Applied Nutrition (CFSAN), U.S. Food and Drug Administration in College Park, MD. In this capacity, Ms. Vierk provides epidemiological support to the various programme offices within CFSAN. Recent responsibilities include food allergens, foodborne outbreaks, working with the Food Safety Office at the World Health Organization on foodborne illness prevalence for different countries, and participation in the development of the CFSAN Adverse Event Reporting System.