Allergenic food extraction method

Allergenic food Raw material (ingredients) Extraction method (preparation)°... 

Allergenic Food Raw Materials (Ingredients) Extraction Method (Preparation)... 

In order to correctly design analytical procedures used for the detection of food allergens, it is necessary to have basic knowledge of food product chemistry to know how to collect, prepare, and store food samples to be able to fragment, mix, disintegrate, and extract samples to know (or be able to find quickly) relevant food quality standards and admissible contents of particular food ingredients and finally to understand precision of determinations, their sensitivity, and detection threshold levels, reproducibility, and errors of determination methods. In addition, it is essential to be able to gather the results of assays, process them with the aid of a computer and statistical methods, and to present the analytically derived data. 

The matrix effect data obtained by adding the target-specific allergenic ingredient protein to the matrix extract [that of foods showing a false positive (crossreactivity) or false negative and that of matrices for which the ELISA method hardly applies] should be fuUy examined and disclosed. 

Of the tree nuts, only the almond and hazelnut kits have been evaluated in independent studies. In December 2004 the Veratox Almond kit completed a full evaluation in seven laboratories that met the criteria for it to be added to Health Canada s Compendium of Food Allergen Methodologies (Health Canada, 2004). Although this evaluation does not confer endorsement of the method, the consistent approach adopted means that the methods can be used for enforcement in Canada should it be required. The study required 630 samples to be analyzed by the laboratories 10 replicates at each of three levels (0, 6.25, and 15.63 ppm) in cookies and in milk and plain chocolate. The kit produced satisfactory results for the matrices and at the levels tested. Analysis of plain chocolate produced the lowest recoveries, as expected, due to the presence of tannins and other phenolic compounds that interfere with the extraction of proteins. 

There are no clear-cut diagnostic tests for food sensitivity. Skin tests are a common and simple method. Drops of the extract of the allergen are administered to the skin through a pinprick. A positive response is recorded if the skin wheals and flares within 20 minutes. This is an indication that IgE specific to the food allergen sits on the surface of the mast cells (21a). See also page 112 for a further explanation. 

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