Page 44 - Food&Drink Magazine August 2019

FOOD TESTING
Challenges in allergen testing
In this second part of a series, Romer Labs senior research scientist Adrian Rogers looks at detecting allergens in processed foods.
FOOD producers are increasingly looking to food allergen analysis as a means of emphasising greater transparency, traceability and integrity in the supply chain. While this growing awareness has extended to validation and verification of factory cleaning and investigation of recalls and incidents, producers are also investigating new ways to detect allergens in processed foods.
Most of the food and drink we consume has been processed or modified in some way. This processing brings about many benefits in terms of food safety, preservation and taste. However, processing changes the characteristics of the ingredients used to make the food, and of particular interest are the changes that allergenic proteins can undergo.
There are many kinds of changes relevant to allergen detection. Allergenic proteins can be subjected to: heat-accelerated chemical reactions including Maillard reactions and other protein-carbohydrate interactions; protein aggregation with loss of solubility; shear effects on protein structure; emulsion formation; pH effects; and water activity during food production.
Recent studies have shown that processing allergens can alter their allergenicity, changing how an allergic individual may
react to them. If immunoassay- based food allergen detection methods rely on the use of antibodies to detect allergens present in food, it follows that the ability to detect them may be affected by processing.
Such processing effects must be taken into account when developing new analytical methods, either by improved extraction methods intended to increase the solubility of the aggregated proteins or by going back to basics and raising new sets of antibodies that specifically target processed allergens.
CREATING REAL-LIFE SAMPLES WITH INCURRED CONTROLS
To evaluate these improved allergen detection methods, incurred sample controls are needed. These are food samples into which a known amount of the food allergen has been incorporated during processing, mimicking as closely as possible the actual conditions under which the sample matrix would normally be manufactured.
Analysing the real-life sample would give the most accurate representation of the recovery and response of a particular method for that particular matrix. Yet each food matrix and processing condition is different and it would not be practical to
evaluate all possibilities with naturally incurred standards. However, evaluation of an
ELISA with one or more typical combinations of food matrix and processing condition is a useful method in determining whether the ELISA can provide reliable results when applied to processed foods.
Steve Taylor from the Food Allergy Research and Resource Program has described what should be considered when creating incurred reference materials for food allergen
incurred materials. Such materials are usually produced in a food processing pilot plant or test kitchen so the ability to clean the processing equipment thoroughly after each batch is an important consideration to assure that there is no batch-to-batch contamination.
Quality control is an important factor when producing incurred reference materials. The allergen to be incorporated into the food matrix must be very well defined. Where official
44 | Food&Drink business | August 2019 | www.foodanddrinkbusiness.com.au
“ Such processing effects must be taken into account when developing new analytical methods, either by improved extraction methods... or by going back to basics.”
analysis. In essence, he suggests the matrix of choice should be one in which the allergenic food residues would likely be found during typical processing in an industrially produced food. The simplest way to do this would be to look around a supermarket and search for similar products with and without the specific allergenic component, for example, a cookie with and without milk.
There are several things to consider when making
reference materials exist, they are not usually affordable in the quantities needed to produce the incurred controls. Yet any official reference materials can be used for comparative purposes to define the nature of the material used.
Furthermore, the homogeneity of the allergen added to the food matrix is critical for every step of the process. In order to ensure that the allergen is homogeneously incorporated into the incurred material,