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From: Food Quality & Safety magazine, October/November 2006

Taking Control

How DNA Technologies Can Help Establish an Effective Allergen Management System

by Terence L.T. Lau, PhD

Food allergy occurs when an individual possesses intolerance to certain types of materials in food, which provokes a hypersensitive reaction of the immune system. It is a major concern to the many people allergic to eggs, peanuts, dairy products, soy, tree nuts (e.g. almonds and cashews), fish, shellfish and wheat, which are commonly referred to by the industry as the Big 8.

Responsible for over 90 percent of all food allergy reactions, the Big 8 can produce a range of reactions from extremely mild – to in the worst-cases of sensitivity – death. Food allergies have accounted for 150 to 200 deaths and an estimated 30,000 visits to the emergency room in the United States each year,1 and they are one of the top 10 leading causes of chronic diseases in the United States, costing the healthcare system nearly $18 billion a year.2 Studies in the European Union and the U.S. have found that many people, even parents of children who have allergies, are unable to discern from food packaging whether a food contains allergens or not. In response, both the EU and U.S. governments created more stringent regulations on the proper labeling of allergens on food packaging. Hong Kong has also slated new, tougher regulations for 2007, which means the food industry will soon need to adhere to a more transparent and effective detection system for food allergens. In order to comply with the new requirements, it will be essential to implement stronger food allergen management systems, which will necessarily include faster, more sensitive, and more reliable testing methods.

How Well Do You Know About Food Allergy?

Food allergies are caused by the overreaction of the immune system (antibodies immunoglobulin E [IgE] and immuno- globulin G [IgG]) towards certain types of food. Symptoms of an allergic reaction can include vomiting, stomach ache, rash, mouth and throat irritation, difficulty in breathing and even death.

According to the European Federation of Allergy and Airways Diseases Patients’ Associations, nearly 12 million Americans suffer from food allergies, with 6.5 million allergic to seafood and three million allergic to peanut or tree nuts.3 In the EU, approximately 4 percent of adults and 8 percent of children out of a total population of 380 million suffer from food allergies. In the new U.S. regulations, it is noted that in a limited review in 1999, some 25 percent of sampled foods from randomly selected manufacturers of baked goods, ice cream and candy failed to list peanuts or eggs on their food labels. It also noted the trend of a rising number of national recalls due to unlabeled allergens. Thus, there is clearly a large need for stronger controls on food safety.

When New Regulations Come In

Both the EU and the U.S. have passed new regulations to govern the labeling of food allergens. The U.S. passed the Food Allergen Labeling and Consumer Protection Act (FALCPA) under the Federal Food, Drug and Cosmetic Act in 2004, which requires that any of the Big 8 be listed on food labels using common language. The EU’s amendments to the food directive added four more allergens to the same big eight that are required in the U.S. for labeling; those being celery, mustard, sesame seeds, and sulphur dioxide and sulphites at concentrations of more than 10 mg/kg or 10 mg/liter.

This is a change from the previous regulations in several important aspects. First, the previous ones did not specify that common language to identify ingredients should be used instead of lesser-known scientific terms. For example, now a label must state any use of milk, rather than the more nebulous terms of casein, sodium caseinate, lactoglobulin or lactalbumin that could be used alone before. Second, it eliminates the previous gap that allowed manufacturers to not list ingredients that, as part of a compound, made up less than 25 percent of a product. FALCPA now requires that food labels indicate the presence of potential allergens used in spices, flavorings, additives and colorings, which were previously exempt from allergen labeling and put people at risk for hidden ingredients.

Penalties for non-compliance under FALCPA include civil sanctions, criminal penalties, and the potential for the seizure of products or for a request for a recall by the manufacturer or distributor.

While a considerable improvement, these new regulations neither apply to meat, poultry, or egg products, which are regulated by the Department of Agriculture, nor do they address the use of advisory labeling in cross-contact situations. Cross-contamination might occur during food processing, for instance, a package of fish product might have a small amount of prawn mixed in it without being noticed by the manufacturer if they are both made using the same equipment.

But these gaps notwithstanding, the new regulations still require the food industry to pay increased attention to food packaging labeling, and many are now investing billions of dollars towards product reformulation, label modification, and even exploring of niche markets.

Incorporation into Current Quality Control Systems

The new regulations are an important addition to the current food quality regime, but will need to be actively incorporated into the dominant quality control processes and systems. Some, such as the standards that ISO applies to overall quality management, broadly attest to the rigorousness of the processes a business has in place. Others, such as HACCP, generally cover the supply chain and production process, but do not necessarily explicitly address allergens. Thus, the identification of allergens could be illuminated using the former, with labeling being identified as a separate element at the critical control point of packaging.

However, even if incorporated into current quality control schemes, an emphasis on allergen testing becomes all the more important when viewed in light of an existing weakness that cannot be addressed through the new regulations, which is that the national and regional nature of such regulations means they may not effectively extend to the global supply chain, even with stipulations to cover imports, as they do.

Southeast Asia and China are major food exporters, and within those countries, manufacturers are not required to comply with the new regulations. This means they are also less likely to possess allergen management systems (AMS), and have less incentive to do so. We could foresee the possibility of trade barriers or delays in production and delivery time when regulations are being more rigorously adhered to. For example, if products were being shipped abroad and unfortunately being held up by customs because of improper labeling, shipping the products back and forth, and conducting the test would cost remarkable time and resources. Moreover, products being placed on the market shelf will post a significant health threat and potential loss to suppliers and manufacturers. A far-sighted company interested in being a global player should still be aware of the threat of potential allergens present in their foods. As evidence of their responsibility, an importer or manufacturer may find it helpful to obtain production certificates and laboratory testing reports to speak to their diligence regarding the presence of allergens in their products. Thus, practicing due diligence when using major allergens as ingredients, and implementing an effective AMS to detect their presence when not desired should be a key part of any business strategy to enhance brand credibility and reputation.

Food Allergen Management System: Basis for Testing

Given the past scope of the problem, the number of people affected by food allergies and the previously inadequate labeling scheme, along with the more exigent demands that will be placed on the food industry by the new regulations, it becomes quite clear that better food allergen management systems with robust detection methods are needed. What method and technology can best perform this task? There exist at the moment two common technologies used for this purpose: Enzyme-linked immunoSorbent assay (ELISA), a test which uses the traditional protein based immunoassay method, and the advanced DNA testing method, which utilizes the polymerase chain reaction (PCR).

ELISA: The Traditional Method

The traditional detection of food allergens utilizes the molecular biology technique called ELISA for protein detection. This common practice of using antibodies to detect for antigens is applied through the preparation of animal monoclonal antibodies, which detects their presence through the confirmation of an allergen. Very often, the detection of food allergens can be achieved through ELISA. These practices are low-cost and easy to operate. However, a major drawback for the protein method is that it is quite easy for cross-reactivity to occur in between the proteins, and this can consequently affect the judgment of the results, and lead to false positive outcomes. Also, due to the fact that protein will denature after heating, this method is not suited for most processed foods and ingredients, as it is prone to failing in detecting allergens in them. In general, ELISA is also less sensitive than polymerase chain reaction (PCR) which will be described below, and therefore any negative result provided by ELISA may either be finally confirmed as negative or be tested as positive by PCR. This would serve as a much better protection for the industry if regulation enforcement agencies utilize PCR as the testing tool.

DNA Testing: A More Comprehensive Protection from Food Allergy

In 1985, American scientist Dr. K. Miller invented what would become one of the most influential DNA analysis technologies – the polymerase chain reaction (PCR). Through DNA replication by polymerase, millions of copies of DNA could be generated in two to three hours, which could be seen by the naked eye.

PCR utilizes a pre-designed sequence of foreign genes and a specific primer set, in the presence of DNA templates, DNA polymerase, dNTPs and magnesium ions, under specific conditions, finish denaturation, annealing and extension steps. After around 30 cycles, the sequence of foreign genes will be greatly amplified. Finally, DNA amplicons will go through electrophoresis and the DNA fragment will be easily detected. Therefore, with only a small amount of sample, PCR can accurately detect for the presence of DNA. Real-time PCR, which provides convenient and fast automated result analysis, can also achieve higher sensitivity and specificity than the traditional immunological testing and is another option for even more sensitive results.

Which One?

Of the two technologies discussed with regards to food allergen testing, DNA testing is the better choice due to its sensitivity and accuracy. Only a tiny amount of allergen DNA is needed for detection, which is important because the law currently imposes a zero tolerance limit for food allergen levels in food samples. Unlike ELISA, DNA testing does not give false positive results, which could be due to cross reactivity in ELISA, and false negative results, due to low sensitivity of ELISA, and can detect for allergens even if the food is cooked or processed.

Thus, DNA testing is a good method to detect food allergens and this advanced method is now widely accepted as being at a mature stage.

DNA Testing: The Concrete Foundation for a Food Allergen Management System

As more countries begin to implement tougher regulations governing the labeling of allergens on food products, the global food industry will find itself under more pressure to ensure the integrity of its products, as well as to effectively communicate this information to their customers. To do this, companies will need to systematically implement more robust food allergen management systems, of which a crucial part will be testing. While there are currently two main technologies for doing this, the traditional protein approach does not always result in dependable outcomes, nor can it be applied to every food. Thus, there is a need for us to explore more advanced methods such as DNA testing, which could be more sensitive, accurate and reliable, even with small sample sizes, and with processed foods, as an alternative or backup. It could serve as a tool to help lower the incidences of unintended allergic reactions, and help prevent the many emergencies and fatalities caused by proper food labeling. An appropriate strategy will allow food companies to guarantee their products, effectively meet regulations, and ensure the health and safety of their customers – thus not only building a responsible reputation as a caring corporate citizen, but also resulting in a safer global food supply.


  1. The Food Allergy & Anaphylaxis Network: New Research Shows Potential for Food-Allergic Reactions from Kissing.
  2. AAAAI. 2000. The Allergy Report. Milwaukee, WI: American Academy of Allergy Asthma and Immunology.
  3. The Food Allergy & Anaphylaxis Network: Food Allergies Now Believed to Affect 1-in-25 Americans According to FAAN Study Released at AAAAI Annual Conference, Americans with Seafood Allergies More Than Double Those with Peanut Allergies.

Terence L.T. LAU, Ph.D. is the chief scientific officer and general manager at HKDNA Chips Limited (Hong Kong). Reach him at or (852) 2111-2123.



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