By Allergen Bureau

Detecting egg allergens in heat-processed food: Overcoming the challenges

Allergen detection methods are an essential tool that allow the screening of ingredients, finished food products and environmental samples for the presence of allergen proteins to ensure the safety of food allergic consumers and compliance with labelling legislation.   

Detection of egg protein is particularly problematic as it is often found in heat-processed foods such as baked goods, pastries, noodles and pasta. The extraction procedures in most commercial egg assays are often not able to efficiently detect egg protein from these sources.  This can cause a 10-100 fold underestimation of egg levels present or even a false-negative result. Importantly, such foods may still trigger an allergic response in egg allergic consumers which can have serious implications.

Underlying this low detection efficiency is the formation of disulphide-linked aggregates of egg-white proteins at high temperatures which are poorly soluble and hinder binding of the detection antibodies. Measurement of egg in heat-processed samples therefore requires the use of reducing agents and surfactants in the extraction procedure to facilitate break-down and solubilization of these cross-linked egg proteins. 

The recently released ELISA Systems Processed Egg assay, ESEGGPR-48, combines the use of a new extraction method with a simple test protocol to allow the rapid detection of both native and processed egg residue.  The new Processed Egg kit meets the challenge of providing the widest matrix applicability while still retaining assay simplicity which provides a valuable tool for allergen management in the food industry. Assay performance has been validated in a variety of sample matrices there has been no identified cross-reactivity.

Contact Elisa Systems for more information.