This invention relates to methods of the detection of enzymatically active enzymes in feed added in the pre-pelleting stage. Further, this invention relates to the field of detecting thermotolerant enzymes added to feed in the pre-pelleting stage. In particular, the invention relates to the detection of a phytase enzyme, in particular an E. coli phytase or an E. coli derived phytase in feed, such as Quantum.TM. Phytase.