Innovative and thorough practice to certify reference materials for sensory defects of olive oil

•Olive oil certified reference materials for training of tasting panels are produced.•Chromatographic fingerprinting is used for homogeneity and stability verifying.•Exploratory data analysis is applied to screen the grouping of batch materials.•Directives are offered to detect & remove outliers from the characterisation study.•Robust statistics is applied on supra-panel data to decide the reference values.