Detection of Food Allergens

The National Institutes of Health estimates that six to seven million people in the U.S. suffer from food allergies. Some of these may develop serious or life-threatening allergic reactions if exposed to the causative proteins. The only way for these people to manage their allergic reactions is to avoid foods containing the proteins. This means that food processors must be careful in informing food allergic consumers about the presence of food allergens in their products.

Section 403 of the Federal Food, Drug, and Cosmetic Act requires food labels to bear a complete listing of all the ingredients in a food. However, because of two narrow exemptions from the ingredient labeling requirements, several allergic-type incidents have occurred. The first exemption provides that spices, flavorings, and colorings may be declared collectively without naming each one. Second, the regulations exempt from ingredient declaration incidental additives, such as processing aids, that are present in a food at insignificant levels and that do not have a technical or functional effect in the finished food. Because of these two exemptions, the Food and Drug Administration believes some individuals may have mistakenly consumed a product to which they are allergic.

FDA is currently considering whether it is necessary to clarify its regulations to ensure that manufacturers fully understand the circumstances in which allergenic food ingredients must be declared and to ensure that sensitive individuals are protected by appropriate labeling.

Although food manufacturers label the ingredients in their products in accordance with these existing regulatory requirements, the Food Allergy Issues Alliance (a private group composed of industry and trade group representatives and a consumer group) has formulated guidelines for the labeling of foods that contain known allergens. The guidelines recommend the use of terms commonly understood by consumers (i.e., “plain English”) for major food allergens within, or in immediate proximity to, the ingredient declaration, to provide clear communication with the food-allergic consumer.

The major food allergens referred to by the guidelines can cause serious allergic reactions in some individuals and account for more than 90% of all food allergies. These major food allergens are peanuts, soybeans, milk, eggs, fish, shellfish, tree nuts (almonds, Brazil nuts, cashews, chestnuts, filberts/hazelnuts, macadamia nuts, pecans, pine nuts, pistachios, and walnuts), and wheat.

The guidelines state that it is important to disclose all allergenic ingredients regardless of the source. They also give procedures for the use of “Supplemental Allergen Statements.” These statements are commonly known as “may contain” labels. These labels are used when there is a chance that foods that do not contain a known allergen as an ingredient may inadvertently come into contact with an allergen during processing. A prominent example would be a processing line that makes a product containing peanuts and then switches over to make another product.

The current FDA stance on allergen labeling is that manufacturers should first adhere to good manufacturing practice (GMP). GMPs are essential for effective reduction of adverse reactions. However, FDA has stated that precautionary labeling with statements such as “may contain (insert name of allergenic ingredient)” may be used. The agency has said that it is open to suggestions on how best to address the issue of allergen labeling.

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FDA is scheduled to hold a public meeting on labeling food allergens on August 13, 2001, in Washington, D.C. Unfortunately, deadlines for this issue prevent reporting on what happened at the meeting. The meeting will discuss the labeling of foods containing allergens and the inadvertent addition of allergens to foods due to processing practices. The purpose of the meeting was to stimulate discussion and to obtain information to assist FDA in determining what additional actions may be necessary to provide consumers with adequate information on product labels. The meeting will focus on three areas: (1) source or plain English labeling; (2) supplemental labeling (e.g., “may contain” labeling); and (3) labeling of ingredients exempted from declaration (i.e., common or usual names of flavorings, spices, and colors; incidental additives). Information on these initiatives is available at the FDA Web site on allergens at www.cfsan.fda.gov/dms/wh-alrgy.html. FDA believes that the Food Allergy Issues Alliance guidelines are an appropriate starting point for discussions at the public meeting.

Manufacturers may want to test final product for the presence of allergens in products not intended to contain allergens. Manufacturer will need to determine what method of analysis is used and the sensitivity of that method. They will also need to determine if the testing is routine or periodic.

Although FDA has not yet designated any method of allergen testing for regulatory purposes, there are several commercial enzyme-linked immuno-sorbent assay (ELISA) kits for food allergens commercially available. Currently, FDA is evaluating some of these kits and is also cooperating with kit manufacturers to conduct international collaborative studies to evaluate the performance of some of the ELISA-based methods.

Neogen Corp., 620 Lasher Place, Lansing, MI 48912 (phone 800-234-5333), offers several ELISA tests for the detection of allergens in food products. These are the Veratox tests for egg allergen, milk allergen, and peanut allergen. The tests are said to require only a minimal amount of training to use, and provide fully quantitative results. Neogen also offers the Alert screening tests for egg, milk, and peanut allergens. These tests provide qualitative results in about 30 min. Neogen’s Alert test for sulfites is said to offer a simple, reliable, and inexpensive method for routine monitoring for sulfite residues in seafood throughout production and distribution.

The Food Allergy Research & Resource Program, 143 Industry Complex, Lincoln, NE 68583 (phone 402-472-4484; www.farrp.unl.edu) was established in 1995 at the U. of Nebraska-Lincoln’s Food Processing Center to assist the food industry with issues associated with food allergens. The group is developing assays to detect allergenic food residues that might contaminate other foods. Currently, the research is focused on ELISAs. These ELISAs detect residues of allergenic foods rather than food allergens and are useful for detecting allergenic food residues arising from such food industry practices as using shared processing equipment or using rework. The group has several ELISAs in various stages of development and works with industry partners to commercialize them into test kits. Assays currently available include peanut, egg, casein, almond, and whey in selected foods. The group is also testing assays for soy, clam, hazelnut, walnut/pecan, and cashew.

Elisa Technologies, Inc., 4581-L NW 6th St., Gainesville, FL 32609 (phone 352-337-3929), offers an assay based on highly specific antibodies to an allergen protein purified from peanuts (Conarachin-A) developed in collaboration between the U.K. Institute of Food Research and Cortecs Diagnostics, Ltd. The assay, marketed as the Elisa-Tek™ Peanut Protein Test Kit, uses the principle of enhanced enzyme-immunoassay (EIA) and is a sensitive and specific test designed to detect very low (ppm) levels of peanut content in raw and cooked foodstuffs. The assay is a non-competitive, sandwich-type EIA. Color development in the assay is proportional to the original amount of Con-A in the extract, and a qualitative determination of peanut protein content may be made either by visual inspection or using a spectrophotometer or plate reader. The company claims that food samples containing the equivalent of 0.5–2 ppm of peanut material, when prepared according to directions, gave positive responses to the test.

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Besides the peanut assay, the company offers kits for the determination of specific food proteins and ingredients including wheat, soy, milk, and egg proteins. Gluten, soy, casein, and whey protein kits may be used to qualitatively detect the respective proteins, or, using a microplate reader and the included standards and controls, the assays will provide quantitative results. The gluten kit has AOAC Official First Action status and is used to identify gluten-free foods. A rapid gluten test that may be used to detect gluten down to 50 ppm in 5 minutes.

The Food Allergy Network, 10400 Eaton Pl., #107, Fairfax, VA 22030 (phone 703-691-3179; www.foodallergy.org) is a non-profit organization established to increase public awareness about food allergies and anaphylaxis. The Web site includes information on product recalls and research summaries.

PRODUCTS & LITERATURE
Indicator Tags for the food processing industry change color only when a batch of food is fully processed. The Retort Canning Process Indicator Tags, for steam pressure cooking low-acid foods, are designed to change from purple to green after exposure to saturated steam in batch processing retort systems. The color change is an effective visual indication of status, and minimizes the danger of unprocessed foods entering the consumer chain. A tag will not complete its color change if an error has occurred in the cooking process. This provides added assurance in addition to existing controls. Leaving the exposed tag on will provide permanent evidence of the food process and demonstrates good practice and traceability. Produced in seven grades, relating to time of exposure and temperature, the retort tags are now available in sequential numbers to eliminate the need for numbering and to provide for greater control in the production area. Temperature ranges available are from 140 to 302°F, and the indicators can be supplied singly or mounted on a card. Free samples are available. For more information, contact Temperature Indicators Ltd., Yewbarrow Studio, Grange-Over-Sands, Cumbria, England, LA11 6ED (phone 011-444-15395-35488; www.temperature-indicators.co.uk) — or circle 305.

Vacuum Desiccator may be used to cool, dry, and store moisture-sensitive material. Applications include storage of thin-layer chromatography plates, halide salt cells, and chemical standards. The one-piece cabinet body is constructed of Fiberglas-reinforced polyester and can be inverted to allow for left-hand opening and closing. Nine shelf supports are molded into the walls of the cabinet to hold two removable aluminum shelves. The cabinet is vacuum tested to 25 in of mercury. A three-way vacuum release needle valve accommodates 1/4-in ID vacuum tubing and allows for slow vacuum release and refilling with dry nitrogen gas. For more information, contact Labconco Corp., 8811 Prospect Ave., Kansas City, MO 64132-2696 (phone 816-333-8811) —or circle 306.

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Plant Integrity Checks, called LifeTime Testing Services, are designed to provide processing line testing with a minimum of disruption to the production process. Contamination is a constant concern during liquid processing, yet the causes can be extremely difficult to track down. The smallest pinhole or hairline crack can be the beginning of major problems unless they are identified and rectified early. However, testing for defects can be a long, disruptive process requiring plant closure and dismantling. This new testing service can check the integrity of heat exchangers, tanks, and vessels in a matter of hours. The testing of heat exchangers is a two-stage operation, first to identify if a defect exists, and then to isolate any faults so that the heat exchanger can be repaired. The first stage is the electrolytic differential analysis test. This entails filling one side of the heat exchanger with sodium sulfate, which acts as an electrolyte, and the other side with water. The pressure of the electrolyte is increased to create a differential, while probes monitor the conductivity of the water. A consistent rise in conductivity of the water indicates that there is a fault somewhere in the system. The next stage is detailed flaw detection, which uses a probe placed at intervals on the edge of each plate. Areas with abnormal sound signature indicate a fault. The heat exchanger can then be repaired. For more information, contact APV Systems, Platinvej 8, DK-6000 Kolding, Denmark (phone +45-7632-4115)—or circle 307.

Mobile Bench may be used as an auxiliary work space and can support loads up to 540 lb. The corrosion-resistant work surface of melamine laminate measures 38 in by 28 in. The height adjusts in four increments, using steel pins with nuts inserted into vertical frame members. The durable welded frame is coated with corrosion and abrasion-resistant baked-on epoxy powder. Toe-locks prevent movement when a stationary bench is required. For more information, contact Labconco Corp., 8811 Prospect Ave., Kansas City, MO 64132-2696 (phone 816-333-8811) —or circle 308.

Dynamic Contact Analyzers, Radian 315 and 322, provide information on contact angle, surface tension, surface energy, wicking, and absorption for solids and powders. Both models are based on digital recording microbalances that provide greater sensitivity and reproducibility. Total travel range is 70 mm with 40 mm programmable range. Maximum sample diameter is 70 mm. Other features shared by both models are temperature range from –10 to 100°C. For more information, contact Thermo Haake, 53 W. Century Rd., Paramus, NJ 07652 (phone 201-265-7865) —or circle 309.

Traceability Coding System, called ECO® or Encoded Character for Optical Technology, combines identification (labeling and marking), certified traceability, and secure documents to provide consumers and processors with a guarantee on the origin and quality of the goods they buy. The system consists of a two-dimensional linear code that incorporates 10–30 times as much information as a conventional bar code in the same space and at comparable resolution. It presents characters in the form of lines that can follow the page setup or not as the user decides. Scratch and abrasion-proof, the system enables all the information generated by an IT system to be encoded such as text, images, sound, or control characters. It can be used with all encryption and sealing techniques. This allows access to certain items of information to be controlled and thus guarantees their integrity and authenticity. The encoding method is therefore suited to the need for traceability. The system makes a descriptive identification possible of the object itself or of its package, providing the user the exact information on its characteristics, origin, or destination. This helps prevent counterfeiting. The link between an object and its attached documents can be guaranteed, to prevent substitutions and multiple links. For more information, contact Eco Sys International, 10 rue Louis VICAT,75015, Paris, France (011-33-156-56-63-56) —or circle 310.

by JAMES GIESE
Internet Editor