Abstract : Throughout its life cycle, an ontology may change in order to adapt to domain changes or to new usages. This paper presents an ontology evolution activity [1] applied to an ontology dedicated to the annotation of experimental data in food [2], and a plug-in, DynarOnto, which assists ontology engineers for carrying out the ontology changes. Our evolution method is an a priori method which takes as input an ontology in a consistent state, implements the changes selected to be applied and manages all the consequences of those changes by producing an ontology in a consistent state.