Food Allergen Testing

Food allergens constitute a high-risk for the food industry. The allergenic protein that causes reactions is highly stable and heat resistant – unlike other risks such as pathogenic bacteria, allergens cannot be removed via a kill step (like cooking or the application of an antimicrobial) once they have been introduced into the supply chain. The only safe course of action is complete segregation of allergens and correct food allergen labelling practices to guide allergic consumers. If products are mislabelled or contamination occurs, an allergic individual may experience a reaction called anaphylactic shock, a potentially deadly condition that is increasingly observed in the population, particularly in children.

 The Codex Alimentarius Commission has laid out science-based standards to guide best practices with regards to allergen. Many countries, including the US, Canada, New Zealand, Australia and the European Union have adopted food allergen testing approaches and labelling practices based on the Codex standards.

The Codex Committee on Food Labelling has listed the foods and ingredients that cause the most severe reactions and most cases of food hypersensitivity. In section 4.2.1.4 of General Standards for the Labelling of Prepackaged Foods it states: “The following foods and ingredients are known to cause hypersensitivity and shall always be declared”:

  • Cereals containing gluten; i.e., wheat, rye, barley, oats, spelt or their hybridized strains and products of these
  • Crustacea and products of these
  • Eggs and egg products
  • Fish and fish products
  • Peanuts, soybeans and products of these
  • Milk and milk products (lactose included)
  • Tree nuts and nut products
  • Sulphite in concentrations of 10 mg/kg or more

Because the importance of food allergens varies between regions, some countries have added other allergens to this list. For instance in 2011 Health Canada designated mustard one of its priority allergens, and as such it is subject to the stringent control and labelling practices brought to bear upon the other allergens of concern, including food allergen testing.

Because there is no way to eliminate a food allergen once it has been introduced, aside from discarding the affected product and sanitizing the environment, it is essential that allergens be controlled at each stage in the supply chain, from primary production to manufacturer to processor to logistics to food handlers to consumers. Examples of Critical Control Points (risks) that relate to allergens include:

  • Packaging (outdated inventory, formulation changes not reflected on label)
  • Personnel (hands, shoes, clothing, crossing over to high-risk areas)
  • Raw materials/supply chain concerns (new suppliers, changes to incoming ingredients)
  • Cleaning (improper segregation of materials, improper sanitation of lines that handle both allergens and allergen-free products)
  • Premises design (lots of cross-over between segregated and non-segregated areas)
  • Equipment design (close proximity of lines producing allergen-free products with those handling allergens, niches where product can become lodged and sheltered from cleaning)
  • Product development/formulation changes

As with any HACCP plan, food allergen testing is an essential element of the monitoring process of CCPs, to assess and improve upon the processes and minimize the chance of contamination. In addition, food allergen testing provides an accurate and efficient way to confirm the efficacy of cleaning by testing surfaces directly, as opposed to the more wasteful methods such as the push-through product mode of cleaning.

In-house food allergen testing is common – commercial kits are widely available that allow processors to swab their products or environments. However, a certain number of tests, particularly those conducted for regulators, need to be accredited. What this means is that the food allergen testing must be conducted by an external laboratory, and further that laboratory and/or test needs to be accredited by an external 3rd party. External labs may also provide expert opinions or advice about food allergens as they impact your particular process or product. For example, if certain processing steps alter the allergenic protein it can make it difficult to detect, or even render a sample unsuitable for a specific test kit. A food testing laboratory would recognize this incompatibility immediately, and may suggest a different test method or taking the sample at a different stage in production.

Food Allergen Testing Technology

The method most commonly used testing to determine food allergen is through an ELISA test kit, which stands for enzyme-linked immunosorbent assay. Generally, after initial collection and preparation of the sample, a series of antibody coatings are pipetted into wells in a plate, along with a tiny amount of the sample in question. The antibodies bind with the sample, forming a sort of “antibody sandwich”. The plates are developed in a dark room, and read in a machine called a spectrometer. Frequencies of light are detected by the machine and interpreted by a technician to determine whether the antibodies had a reaction with the target allergenic proteins, signalling the presence of an allergen. ELISA test kits are designed to detect one allergen at a time – for this reason numerous tests may be needed to detect multiple allergens of interest. Results from an ELISA test take approximately 24 hours, however external labs will have varying turn-around times based on their operations.

Generally, ELISA test kits can be used for food allergen testing both directly in food products and on swabs collected from food contact surfaces, packaging or equipment surfaces. Food allergen testing in raw incoming ingredients and the processing or food service environment provides early detection or reveals trends that signal potential risk.

A large market exists for allergen-free foods, gluten-free, lactose-free and so on. Companies have seen growth in the area of peanut-free and other school lunch-friendly items that protect allergic individuals and provide a trusted source of safe food.

Beyond food allergen testing for the purpose of segregation, research is being conducted to develop methods for lessening or eliminating allergic reactions in the population. For instance, studies have shown that feeding mice peptides – or portions of the allergenic protein that cause reactions – has shown dramatic reductions in the occurrence and/or severity of reactions. In the future, it may be possible to add safe peptides to products aimed at children, to help them develop tolerance and outgrow their allergies over time.

Currently, however, there is no course of action for the food industry to take other than the complete segregation of allergens, through the use of stringent hygiene procedures, quality control, food allergen testing, and operational controls like labelling and packaging practices.

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