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The project goal is to improve the assessment of the residual allergenicity of processed foods by evaluating existing detection methods and developing improved methods. The food industry needs simple, rugged analytical methods that can be used to assess the effectiveness of allergen control programs including especially the adequacy of cleaning of shared equipment. If the existing kits cannot reliably detect residues of allergenic foods following processing, then industry risk assessments may be misleading. <P>The objectives are: 1) To assess the effects of various types of processing on allergenic foods and the specific allergens contained therein and methods for their detection using the model food systems, and 2) To improve methods for the detection of allergen residues in foods after processing.<P> In the first objective, the focus will be on model foods prepared with known amounts of peanut or milk residues and then subjected to numerous food processing unit operations. The effectiveness of various commercial ELISA methods will be determined as assessed by the percent recovery of the expected residues following processing. <P>Based on preliminary findings with recovery of milk residues after several heat-processing operations, the ELISAs are predicted to have deficiencies in detection. The commercial ELISAs will also be compared to IgE-based immunoassays. If so, then various approaches will be attempted to improve the post-processing detection of milk and peanut protein residues including more aggressive extraction techniques, production of antibodies specific to heat-processed antigens, and the development of oligoclonal ELISAs.
Non-Technical Summary: Food processing operations can affect the allergenicity of foods by causing changes in the protein allergens that trigger allergic reactions. The processing-induced changes can include physical removal of allergens, changes in the secondary and tertiary structures of the allergnic protein, chemical modifications, and changes to the primary structure of the allergenic proteins through proteolysis including fermentation. However, the assessment of the residual allergenicity of processed foods can be very challenging because analytical methods often depend upon the solubility and antigenic reactivity of the allergenic protein. Preliminary results indicate that the detection of milk residues is diminished by thermal processing. This proposal aims to do a more thorough assessment of the effects of a range of processing methods, including both physical and biological processes, on the detection of residues of two key allergenic foods, milk and peanut, using the most common commercial assays. Based on the preliminary results, the likelihood exists that these current methods will not be sufficiently robust. Thus the final phase of the project will involve the development of improved approaches to residue detection such as oligoclonal immunoassays, use of processing-altered antigens to make better antibodies, use of more aggressive extraction methods and various combined approaches. <P> Approach: Model solid and liquid foods will be developed with known incorporated amounts of milk and peanut. These model foods will be subjected to a range of processing methods ranging from boiling and baking to ultrasonic processing, UHT processing, and fermentation. The detection of residues of milk and peanut before and after processing will be compared with commercial milk and peanut ELISAs, component-resolved detection of specific allergens, and detection of specific allergens by use of serum IgE-binding assays. If the commercial assays are deficient, then improved approaches will be sought such as enhanced extraction methods, production of antisera against processed antigens, and the development of oligoclonal ELISAs using antibodies prepared against specific peptides.