scope:

This guideline describes the basic procedure and the requirements of methods based on immunochemical detection for the extraction and qualitative and quantitative determination of Bt proteins from genetically modified plant residues found on the field after harvesting, and soil samples which have come into contact with these plants. The specificity of the methods for the Bt proteins depends on the specificity of the antibodies used. In some circumstances, immunoreactive degradation products may also be detected, which prevents the immediate detection of the biological, e. g. insecticidal activity of these proteins. Depending on the specificity of the immunochemical detection concerned, a priori cross reactions with naturally occurring Bt proteins, such as those produced by Bacillus thuringiensis strains present in soil, cannot be ruled out.